Repository: rust-lang/rust-analyzer
Pull request #12997 (2022-08-11 08:41:54)

fix: Fix panic in `no_such_field` when using tuple fields on record structs


Patch:
diff --git a/crates/hir-expand/src/builtin_fn_macro.rs b/crates/hir-expand/src/builtin_fn_macro.rs
index 8befa7f7da..c21b35cdc0 100644
--- a/crates/hir-expand/src/builtin_fn_macro.rs
+++ b/crates/hir-expand/src/builtin_fn_macro.rs
@@ -251,13 +251,9 @@ fn format_args_expand(
     }
     for arg in &mut args {
         // Remove `key =`.
-        if matches!(arg.token_trees.get(1), Some(tt::TokenTree::Leaf(tt::Leaf::Punct(p))) if p.char == '=')
+        if matches!(arg.token_trees.get(1), Some(tt::TokenTree::Leaf(tt::Leaf::Punct(p))) if p.char == '=' && p.spacing != tt::Spacing::Joint)
         {
-            // but not with `==`
-            if !matches!(arg.token_trees.get(2), Some(tt::TokenTree::Leaf(tt::Leaf::Punct(p))) if p.char == '=' )
-            {
-                arg.token_trees.drain(..2);
-            }
+            arg.token_trees.drain(..2);
         }
     }
     let _format_string = args.remove(0);
diff --git a/crates/hir-expand/src/fixup.rs b/crates/hir-expand/src/fixup.rs
index 893e6fe4b8..46257b6bc4 100644
--- a/crates/hir-expand/src/fixup.rs
+++ b/crates/hir-expand/src/fixup.rs
@@ -468,7 +468,7 @@ fn foo() {
 }
 "#,
             expect![[r#"
-fn foo () {a .__ra_fixup}
+fn foo () {a . __ra_fixup}
 "#]],
         )
     }
@@ -478,11 +478,11 @@ fn foo () {a .__ra_fixup}
         check(
             r#"
 fn foo() {
-    a.;
+    a. ;
 }
 "#,
             expect![[r#"
-fn foo () {a .__ra_fixup ;}
+fn foo () {a . __ra_fixup ;}
 "#]],
         )
     }
@@ -492,12 +492,12 @@ fn foo () {a .__ra_fixup ;}
         check(
             r#"
 fn foo() {
-    a.;
+    a. ;
     bar();
 }
 "#,
             expect![[r#"
-fn foo () {a .__ra_fixup ; bar () ;}
+fn foo () {a . __ra_fixup ; bar () ;}
 "#]],
         )
     }
@@ -525,7 +525,7 @@ fn foo() {
 }
 "#,
             expect![[r#"
-fn foo () {let x = a .__ra_fixup ;}
+fn foo () {let x = a . __ra_fixup ;}
 "#]],
         )
     }
@@ -541,7 +541,7 @@ fn foo() {
 }
 "#,
             expect![[r#"
-fn foo () {a .b ; bar () ;}
+fn foo () {a . b ; bar () ;}
 "#]],
         )
     }
diff --git a/crates/hir-ty/src/infer/pat.rs b/crates/hir-ty/src/infer/pat.rs
index 53259d66de..5e7320a5dd 100644
--- a/crates/hir-ty/src/infer/pat.rs
+++ b/crates/hir-ty/src/infer/pat.rs
@@ -14,9 +14,8 @@ use crate::{
     consteval::intern_const_scalar,
     infer::{BindingMode, Expectation, InferenceContext, TypeMismatch},
     lower::lower_to_chalk_mutability,
-    primitive::UintTy,
-    static_lifetime, ConcreteConst, ConstValue, Interner, Scalar, Substitution, Ty, TyBuilder,
-    TyExt, TyKind,
+    static_lifetime, ConcreteConst, ConstValue, Interner, Substitution, Ty, TyBuilder, TyExt,
+    TyKind,
 };
 
 use super::PatLike;
@@ -295,29 +294,7 @@ impl<'a> InferenceContext<'a> {
                 let start_ty = self.infer_expr(*start, &Expectation::has_type(expected.clone()));
                 self.infer_expr(*end, &Expectation::has_type(start_ty))
             }
-            &Pat::Lit(expr) => {
-                // FIXME: using `Option` here is a workaround until we can use if-let chains in stable.
-                let mut pat_ty = None;
-
-                // Like slice patterns, byte string patterns can denote both `&[u8; N]` and `&[u8]`.
-                if let Expr::Literal(Literal::ByteString(_)) = self.body[expr] {
-                    if let Some((inner, ..)) = expected.as_reference() {
-                        let inner = self.resolve_ty_shallow(inner);
-                        if matches!(inner.kind(Interner), TyKind::Slice(_)) {
-                            let elem_ty = TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(Interner);
-                            let slice_ty = TyKind::Slice(elem_ty).intern(Interner);
-                            let ty = TyKind::Ref(Mutability::Not, static_lifetime(), slice_ty)
-                                .intern(Interner);
-                            self.write_expr_ty(expr, ty.clone());
-                            pat_ty = Some(ty);
-                        }
-                    }
-                }
-
-                pat_ty.unwrap_or_else(|| {
-                    self.infer_expr(expr, &Expectation::has_type(expected.clone()))
-                })
-            }
+            Pat::Lit(expr) => self.infer_expr(*expr, &Expectation::has_type(expected.clone())),
             Pat::Box { inner } => match self.resolve_boxed_box() {
                 Some(box_adt) => {
                     let (inner_ty, alloc_ty) = match expected.as_adt() {
@@ -366,9 +343,7 @@ fn is_non_ref_pat(body: &hir_def::body::Body, pat: PatId) -> bool {
         // FIXME: ConstBlock/Path/Lit might actually evaluate to ref, but inference is unimplemented.
         Pat::Path(..) => true,
         Pat::ConstBlock(..) => true,
-        Pat::Lit(expr) => {
-            !matches!(body[*expr], Expr::Literal(Literal::String(..) | Literal::ByteString(..)))
-        }
+        Pat::Lit(expr) => !matches!(body[*expr], Expr::Literal(Literal::String(..))),
         Pat::Bind {
             mode: BindingAnnotation::Mutable | BindingAnnotation::Unannotated,
             subpat: Some(subpat),
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index f5e2e44307..ae2896e193 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -368,6 +368,7 @@ impl SourceAnalyzer {
         let local = if field.name_ref().is_some() {
             None
         } else {
+            // Shorthand syntax, resolve to the local
             let path = ModPath::from_segments(PathKind::Plain, once(local_name.clone()));
             match self.resolver.resolve_path_in_value_ns_fully(db.upcast(), &path) {
                 Some(ValueNs::LocalBinding(pat_id)) => {
diff --git a/crates/ide-assists/src/handlers/add_missing_impl_members.rs b/crates/ide-assists/src/handlers/add_missing_impl_members.rs
index 62cf5ab4f3..c808c010c6 100644
--- a/crates/ide-assists/src/handlers/add_missing_impl_members.rs
+++ b/crates/ide-assists/src/handlers/add_missing_impl_members.rs
@@ -944,7 +944,7 @@ foo!();
 struct Foo(usize);
 
 impl FooB for Foo {
-    $0fn foo<'lt>(&'lt self){}
+    $0fn foo< 'lt>(& 'lt self){}
 }
 "#,
         )
diff --git a/crates/ide-completion/src/completions.rs b/crates/ide-completion/src/completions.rs
index 55c3e28392..72579e6026 100644
--- a/crates/ide-completion/src/completions.rs
+++ b/crates/ide-completion/src/completions.rs
@@ -617,6 +617,7 @@ pub(super) fn complete_name_ref(
 
                     dot::complete_undotted_self(acc, ctx, path_ctx, expr_ctx);
                     item_list::complete_item_list_in_expr(acc, ctx, path_ctx, expr_ctx);
+                    record::complete_record_expr_func_update(acc, ctx, path_ctx, expr_ctx);
                     snippet::complete_expr_snippet(acc, ctx, path_ctx, expr_ctx);
                 }
                 PathKind::Type { location } => {
diff --git a/crates/ide-completion/src/completions/expr.rs b/crates/ide-completion/src/completions/expr.rs
index 4d66af9e8d..5d0ddaaf2a 100644
--- a/crates/ide-completion/src/completions/expr.rs
+++ b/crates/ide-completion/src/completions/expr.rs
@@ -1,10 +1,8 @@
 //! Completion of names from the current scope in expression position.
 
 use hir::ScopeDef;
-use syntax::ast;
 
 use crate::{
-    completions::record::add_default_update,
     context::{ExprCtx, PathCompletionCtx, Qualified},
     CompletionContext, Completions,
 };
@@ -221,78 +219,60 @@ pub(crate) fn complete_expr_path(
                 _ => (),
             });
 
-            match is_func_update {
-                Some(record_expr) => {
-                    let ty = ctx.sema.type_of_expr(&ast::Expr::RecordExpr(record_expr.clone()));
+            if is_func_update.is_none() {
+                let mut add_keyword =
+                    |kw, snippet| acc.add_keyword_snippet_expr(ctx, incomplete_let, kw, snippet);
 
-                    match ty.as_ref().and_then(|t| t.original.as_adt()) {
-                        Some(hir::Adt::Union(_)) => (),
-                        _ => {
-                            cov_mark::hit!(functional_update);
-                            let missing_fields =
-                                ctx.sema.record_literal_missing_fields(record_expr);
-                            if !missing_fields.is_empty() {
-                                add_default_update(acc, ctx, ty);
-                            }
-                        }
-                    };
+                if !in_block_expr {
+                    add_keyword("unsafe", "unsafe {\n    $0\n}");
                 }
-                None => {
-                    let mut add_keyword = |kw, snippet| {
-                        acc.add_keyword_snippet_expr(ctx, incomplete_let, kw, snippet)
-                    };
-
-                    if !in_block_expr {
-                        add_keyword("unsafe", "unsafe {\n    $0\n}");
-                    }
-                    add_keyword("match", "match $1 {\n    $0\n}");
-                    add_keyword("while", "while $1 {\n    $0\n}");
-                    add_keyword("while let", "while let $1 = $2 {\n    $0\n}");
-                    add_keyword("loop", "loop {\n    $0\n}");
-                    if in_match_guard {
-                        add_keyword("if", "if $0");
-                    } else {
-                        add_keyword("if", "if $1 {\n    $0\n}");
-                    }
-                    add_keyword("if let", "if let $1 = $2 {\n    $0\n}");
-                    add_keyword("for", "for $1 in $2 {\n    $0\n}");
-                    add_keyword("true", "true");
-                    add_keyword("false", "false");
+                add_keyword("match", "match $1 {\n    $0\n}");
+                add_keyword("while", "while $1 {\n    $0\n}");
+                add_keyword("while let", "while let $1 = $2 {\n    $0\n}");
+                add_keyword("loop", "loop {\n    $0\n}");
+                if in_match_guard {
+                    add_keyword("if", "if $0");
+                } else {
+                    add_keyword("if", "if $1 {\n    $0\n}");
+                }
+                add_keyword("if let", "if let $1 = $2 {\n    $0\n}");
+                add_keyword("for", "for $1 in $2 {\n    $0\n}");
+                add_keyword("true", "true");
+                add_keyword("false", "false");
 
-                    if in_condition || in_block_expr {
-                        add_keyword("let", "let");
-                    }
+                if in_condition || in_block_expr {
+                    add_keyword("let", "let");
+                }
 
-                    if after_if_expr {
-                        add_keyword("else", "else {\n    $0\n}");
-                        add_keyword("else if", "else if $1 {\n    $0\n}");
-                    }
+                if after_if_expr {
+                    add_keyword("else", "else {\n    $0\n}");
+                    add_keyword("else if", "else if $1 {\n    $0\n}");
+                }
 
-                    if wants_mut_token {
-                        add_keyword("mut", "mut ");
-                    }
+                if wants_mut_token {
+                    add_keyword("mut", "mut ");
+                }
 
-                    if in_loop_body {
-                        if in_block_expr {
-                            add_keyword("continue", "continue;");
-                            add_keyword("break", "break;");
-                        } else {
-                            add_keyword("continue", "continue");
-                            add_keyword("break", "break");
-                        }
+                if in_loop_body {
+                    if in_block_expr {
+                        add_keyword("continue", "continue;");
+                        add_keyword("break", "break;");
+                    } else {
+                        add_keyword("continue", "continue");
+                        add_keyword("break", "break");
                     }
+                }
 
-                    if let Some(ty) = innermost_ret_ty {
-                        add_keyword(
-                            "return",
-                            match (in_block_expr, ty.is_unit()) {
-                                (true, true) => "return ;",
-                                (true, false) => "return;",
-                                (false, true) => "return $0",
-                                (false, false) => "return",
-                            },
-                        );
-                    }
+                if let Some(ty) = innermost_ret_ty {
+                    add_keyword(
+                        "return",
+                        match (in_block_expr, ty.is_unit()) {
+                            (true, true) => "return ;",
+                            (true, false) => "return;",
+                            (false, true) => "return $0",
+                            (false, false) => "return",
+                        },
+                    );
                 }
             }
         }
diff --git a/crates/ide-completion/src/completions/record.rs b/crates/ide-completion/src/completions/record.rs
index bfb98b9f27..1c9042390d 100644
--- a/crates/ide-completion/src/completions/record.rs
+++ b/crates/ide-completion/src/completions/record.rs
@@ -3,7 +3,7 @@ use ide_db::SymbolKind;
 use syntax::ast::{self, Expr};
 
 use crate::{
-    context::{DotAccess, DotAccessKind, PatternContext},
+    context::{DotAccess, DotAccessKind, ExprCtx, PathCompletionCtx, PatternContext, Qualified},
     CompletionContext, CompletionItem, CompletionItemKind, CompletionRelevance,
     CompletionRelevancePostfixMatch, Completions,
 };
@@ -14,24 +14,7 @@ pub(crate) fn complete_record_pattern_fields(
     pattern_ctx: &PatternContext,
 ) {
     if let PatternContext { record_pat: Some(record_pat), .. } = pattern_ctx {
-        let ty = ctx.sema.type_of_pat(&ast::Pat::RecordPat(record_pat.clone()));
-        let missing_fields = match ty.as_ref().and_then(|t| t.original.as_adt()) {
-            Some(hir::Adt::Union(un)) => {
-                // ctx.sema.record_pat_missing_fields will always return
-                // an empty Vec on a union literal. This is normally
-                // reasonable, but here we'd like to present the full list
-                // of fields if the literal is empty.
-                let were_fields_specified =
-                    record_pat.record_pat_field_list().and_then(|fl| fl.fields().next()).is_some();
-
-                match were_fields_specified {
-                    false => un.fields(ctx.db).into_iter().map(|f| (f, f.ty(ctx.db))).collect(),
-                    true => return,
-                }
-            }
-            _ => ctx.sema.record_pattern_missing_fields(record_pat),
-        };
-        complete_fields(acc, ctx, missing_fields);
+        complete_fields(acc, ctx, ctx.sema.record_pattern_missing_fields(record_pat));
     }
 }
 
@@ -59,13 +42,8 @@ pub(crate) fn complete_record_expr_fields(
         }
         _ => {
             let missing_fields = ctx.sema.record_literal_missing_fields(record_expr);
-
-            if !missing_fields.is_empty() {
-                cov_mark::hit!(functional_update_field);
-                add_default_update(acc, ctx, ty);
-            }
+            add_default_update(acc, ctx, ty, &missing_fields);
             if dot_prefix {
-                cov_mark::hit!(functional_update_one_dot);
                 let mut item =
                     CompletionItem::new(CompletionItemKind::Snippet, ctx.source_range(), "..");
                 item.insert_text(".");
@@ -78,18 +56,41 @@ pub(crate) fn complete_record_expr_fields(
     complete_fields(acc, ctx, missing_fields);
 }
 
-pub(crate) fn add_default_update(
+// FIXME: This should probably be part of complete_path_expr
+pub(crate) fn complete_record_expr_func_update(
+    acc: &mut Completions,
+    ctx: &CompletionContext<'_>,
+    path_ctx: &PathCompletionCtx,
+    expr_ctx: &ExprCtx,
+) {
+    if !matches!(path_ctx.qualified, Qualified::No) {
+        return;
+    }
+    if let ExprCtx { is_func_update: Some(record_expr), .. } = expr_ctx {
+        let ty = ctx.sema.type_of_expr(&Expr::RecordExpr(record_expr.clone()));
+
+        match ty.as_ref().and_then(|t| t.original.as_adt()) {
+            Some(hir::Adt::Union(_)) => (),
+            _ => {
+                let missing_fields = ctx.sema.record_literal_missing_fields(record_expr);
+                add_default_update(acc, ctx, ty, &missing_fields);
+            }
+        };
+    }
+}
+
+fn add_default_update(
     acc: &mut Completions,
     ctx: &CompletionContext<'_>,
     ty: Option<hir::TypeInfo>,
+    missing_fields: &[(hir::Field, hir::Type)],
 ) {
     let default_trait = ctx.famous_defs().core_default_Default();
-    let impls_default_trait = default_trait
+    let impl_default_trait = default_trait
         .zip(ty.as_ref())
         .map_or(false, |(default_trait, ty)| ty.original.impls_trait(ctx.db, default_trait, &[]));
-    if impls_default_trait {
+    if impl_default_trait && !missing_fields.is_empty() {
         // FIXME: This should make use of scope_def like completions so we get all the other goodies
-        // that is we should handle this like actually completing the default function
         let completion_text = "..Default::default()";
         let mut item = CompletionItem::new(SymbolKind::Field, ctx.source_range(), completion_text);
         let completion_text =
diff --git a/crates/ide-completion/src/context.rs b/crates/ide-completion/src/context.rs
index 759742d347..e35f79d2b6 100644
--- a/crates/ide-completion/src/context.rs
+++ b/crates/ide-completion/src/context.rs
@@ -134,7 +134,6 @@ pub(crate) struct ExprCtx {
     pub(crate) in_condition: bool,
     pub(crate) incomplete_let: bool,
     pub(crate) ref_expr_parent: Option<ast::RefExpr>,
-    /// The surrounding RecordExpression we are completing a functional update
     pub(crate) is_func_update: Option<ast::RecordExpr>,
     pub(crate) self_param: Option<hir::SelfParam>,
     pub(crate) innermost_ret_ty: Option<hir::Type>,
diff --git a/crates/ide-diagnostics/src/handlers/no_such_field.rs b/crates/ide-diagnostics/src/handlers/no_such_field.rs
index e032c578f0..a80299106b 100644
--- a/crates/ide-diagnostics/src/handlers/no_such_field.rs
+++ b/crates/ide-diagnostics/src/handlers/no_such_field.rs
@@ -68,7 +68,7 @@ fn missing_record_expr_field_fixes(
     }
     let new_field = make::record_field(
         None,
-        make::name(&record_expr_field.field_name()?.text()),
+        make::name(&record_expr_field.field_name()?.ident_token()?.text()),
         make::ty(&new_field_type.display_source_code(sema.db, module.into()).ok()?),
     );
 
@@ -109,7 +109,7 @@ fn missing_record_expr_field_fixes(
 
 #[cfg(test)]
 mod tests {
-    use crate::tests::{check_diagnostics, check_fix};
+    use crate::tests::{check_diagnostics, check_fix, check_no_fix};
 
     #[test]
     fn no_such_field_diagnostics() {
@@ -277,6 +277,20 @@ struct Foo {
     bar: i32,
     pub(crate) baz: bool
 }
+"#,
+        )
+    }
+
+    #[test]
+    fn test_tuple_field_on_record_struct() {
+        check_no_fix(
+            r#"
+struct Struct {}
+fn main() {
+    Struct {
+        0$0: 0
+    }
+}
 "#,
         )
     }
diff --git a/crates/mbe/src/syntax_bridge.rs b/crates/mbe/src/syntax_bridge.rs
index e4c56565b9..aca6ecd424 100644
--- a/crates/mbe/src/syntax_bridge.rs
+++ b/crates/mbe/src/syntax_bridge.rs
@@ -228,7 +228,16 @@ fn convert_tokens<C: TokenConvertor>(conv: &mut C) -> tt::Subtree {
             }
 
             let spacing = match conv.peek().map(|next| next.kind(conv)) {
-                Some(kind) if !kind.is_trivia() => tt::Spacing::Joint,
+                Some(kind)
+                    if !kind.is_trivia()
+                        && kind.is_punct()
+                        && kind != T!['[']
+                        && kind != T!['{']
+                        && kind != T!['(']
+                        && kind != UNDERSCORE =>
+                {
+                    tt::Spacing::Joint
+                }
                 _ => tt::Spacing::Alone,
             };
             let char = match token.to_char(conv) {
diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs
index dcaceade65..e7402104eb 100644
--- a/crates/parser/src/grammar/expressions.rs
+++ b/crates/parser/src/grammar/expressions.rs
@@ -564,10 +564,8 @@ fn path_expr(p: &mut Parser<'_>, r: Restrictions) -> (CompletedMarker, BlockLike
 // test record_lit
 // fn foo() {
 //     S {};
-//     S { x };
 //     S { x, y: 32, };
 //     S { x, y: 32, ..Default::default() };
-//     S { x: ::default() };
 //     TupleStruct { 0: 1 };
 // }
 pub(crate) fn record_expr_field_list(p: &mut Parser<'_>) {
@@ -584,26 +582,16 @@ pub(crate) fn record_expr_field_list(p: &mut Parser<'_>) {
 
         match p.current() {
             IDENT | INT_NUMBER => {
-                // test_err record_literal_missing_ellipsis_recovery
+                // test_err record_literal_before_ellipsis_recovery
                 // fn main() {
-                //     S { S::default() }
+                //     S { field ..S::default() }
                 // }
-                if p.nth_at(1, T![::]) {
-                    m.abandon(p);
-                    p.expect(T![..]);
-                    expr(p);
-                } else {
-                    // test_err record_literal_before_ellipsis_recovery
-                    // fn main() {
-                    //     S { field ..S::default() }
-                    // }
-                    if p.nth_at(1, T![:]) || p.nth_at(1, T![..]) {
-                        name_ref_or_index(p);
-                        p.expect(T![:]);
-                    }
-                    expr(p);
-                    m.complete(p, RECORD_EXPR_FIELD);
+                if p.nth_at(1, T![:]) || p.nth_at(1, T![..]) {
+                    name_ref_or_index(p);
+                    p.expect(T![:]);
                 }
+                expr(p);
+                m.complete(p, RECORD_EXPR_FIELD);
             }
             T![.] if p.at(T![..]) => {
                 m.abandon(p);
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/mod.rs b/crates/proc-macro-srv/src/abis/abi_1_64/mod.rs
new file mode 100644
index 0000000000..9d56f0eaf8
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/mod.rs
@@ -0,0 +1,105 @@
+//! Proc macro ABI.
+
+#[allow(dead_code)]
+#[doc(hidden)]
+mod proc_macro;
+
+#[allow(dead_code)]
+#[doc(hidden)]
+mod ra_server;
+
+use libloading::Library;
+use proc_macro_api::ProcMacroKind;
+
+use super::PanicMessage;
+
+pub use ra_server::TokenStream;
+
+pub(crate) struct Abi {
+    exported_macros: Vec<proc_macro::bridge::client::ProcMacro>,
+}
+
+impl From<proc_macro::bridge::PanicMessage> for PanicMessage {
+    fn from(p: proc_macro::bridge::PanicMessage) -> Self {
+        Self { message: p.as_str().map(|s| s.to_string()) }
+    }
+}
+
+impl Abi {
+    pub unsafe fn from_lib(lib: &Library, symbol_name: String) -> Result<Abi, libloading::Error> {
+        let macros: libloading::Symbol<'_, &&[proc_macro::bridge::client::ProcMacro]> =
+            lib.get(symbol_name.as_bytes())?;
+        Ok(Self { exported_macros: macros.to_vec() })
+    }
+
+    pub fn expand(
+        &self,
+        macro_name: &str,
+        macro_body: &tt::Subtree,
+        attributes: Option<&tt::Subtree>,
+    ) -> Result<tt::Subtree, PanicMessage> {
+        let parsed_body = TokenStream::with_subtree(macro_body.clone());
+
+        let parsed_attributes =
+            attributes.map_or(TokenStream::new(), |attr| TokenStream::with_subtree(attr.clone()));
+
+        for proc_macro in &self.exported_macros {
+            match proc_macro {
+                proc_macro::bridge::client::ProcMacro::CustomDerive {
+                    trait_name, client, ..
+                } if *trait_name == macro_name => {
+                    let res = client.run(
+                        &proc_macro::bridge::server::SameThread,
+                        ra_server::RustAnalyzer::default(),
+                        parsed_body,
+                        true,
+                    );
+                    return res.map(|it| it.into_subtree()).map_err(PanicMessage::from);
+                }
+                proc_macro::bridge::client::ProcMacro::Bang { name, client }
+                    if *name == macro_name =>
+                {
+                    let res = client.run(
+                        &proc_macro::bridge::server::SameThread,
+                        ra_server::RustAnalyzer::default(),
+                        parsed_body,
+                        true,
+                    );
+                    return res.map(|it| it.into_subtree()).map_err(PanicMessage::from);
+                }
+                proc_macro::bridge::client::ProcMacro::Attr { name, client }
+                    if *name == macro_name =>
+                {
+                    let res = client.run(
+                        &proc_macro::bridge::server::SameThread,
+                        ra_server::RustAnalyzer::default(),
+                        parsed_attributes,
+                        parsed_body,
+                        true,
+                    );
+                    return res.map(|it| it.into_subtree()).map_err(PanicMessage::from);
+                }
+                _ => continue,
+            }
+        }
+
+        Err(proc_macro::bridge::PanicMessage::String("Nothing to expand".to_string()).into())
+    }
+
+    pub fn list_macros(&self) -> Vec<(String, ProcMacroKind)> {
+        self.exported_macros
+            .iter()
+            .map(|proc_macro| match proc_macro {
+                proc_macro::bridge::client::ProcMacro::CustomDerive { trait_name, .. } => {
+                    (trait_name.to_string(), ProcMacroKind::CustomDerive)
+                }
+                proc_macro::bridge::client::ProcMacro::Bang { name, .. } => {
+                    (name.to_string(), ProcMacroKind::FuncLike)
+                }
+                proc_macro::bridge::client::ProcMacro::Attr { name, .. } => {
+                    (name.to_string(), ProcMacroKind::Attr)
+                }
+            })
+            .collect()
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/buffer.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/buffer.rs
new file mode 100644
index 0000000000..48030f8d82
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/buffer.rs
@@ -0,0 +1,156 @@
+//! Buffer management for same-process client<->server communication.
+
+use std::io::{self, Write};
+use std::mem;
+use std::ops::{Deref, DerefMut};
+use std::slice;
+
+#[repr(C)]
+pub struct Buffer {
+    data: *mut u8,
+    len: usize,
+    capacity: usize,
+    reserve: extern "C" fn(Buffer, usize) -> Buffer,
+    drop: extern "C" fn(Buffer),
+}
+
+unsafe impl Sync for Buffer {}
+unsafe impl Send for Buffer {}
+
+impl Default for Buffer {
+    #[inline]
+    fn default() -> Self {
+        Self::from(vec![])
+    }
+}
+
+impl Deref for Buffer {
+    type Target = [u8];
+    #[inline]
+    fn deref(&self) -> &[u8] {
+        unsafe { slice::from_raw_parts(self.data as *const u8, self.len) }
+    }
+}
+
+impl DerefMut for Buffer {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut [u8] {
+        unsafe { slice::from_raw_parts_mut(self.data, self.len) }
+    }
+}
+
+impl Buffer {
+    #[inline]
+    pub(super) fn new() -> Self {
+        Self::default()
+    }
+
+    #[inline]
+    pub(super) fn clear(&mut self) {
+        self.len = 0;
+    }
+
+    #[inline]
+    pub(super) fn take(&mut self) -> Self {
+        mem::take(self)
+    }
+
+    // We have the array method separate from extending from a slice. This is
+    // because in the case of small arrays, codegen can be more efficient
+    // (avoiding a memmove call). With extend_from_slice, LLVM at least
+    // currently is not able to make that optimization.
+    #[inline]
+    pub(super) fn extend_from_array<const N: usize>(&mut self, xs: &[u8; N]) {
+        if xs.len() > (self.capacity - self.len) {
+            let b = self.take();
+            *self = (b.reserve)(b, xs.len());
+        }
+        unsafe {
+            xs.as_ptr().copy_to_nonoverlapping(self.data.add(self.len), xs.len());
+            self.len += xs.len();
+        }
+    }
+
+    #[inline]
+    pub(super) fn extend_from_slice(&mut self, xs: &[u8]) {
+        if xs.len() > (self.capacity - self.len) {
+            let b = self.take();
+            *self = (b.reserve)(b, xs.len());
+        }
+        unsafe {
+            xs.as_ptr().copy_to_nonoverlapping(self.data.add(self.len), xs.len());
+            self.len += xs.len();
+        }
+    }
+
+    #[inline]
+    pub(super) fn push(&mut self, v: u8) {
+        // The code here is taken from Vec::push, and we know that reserve()
+        // will panic if we're exceeding isize::MAX bytes and so there's no need
+        // to check for overflow.
+        if self.len == self.capacity {
+            let b = self.take();
+            *self = (b.reserve)(b, 1);
+        }
+        unsafe {
+            *self.data.add(self.len) = v;
+            self.len += 1;
+        }
+    }
+}
+
+impl Write for Buffer {
+    #[inline]
+    fn write(&mut self, xs: &[u8]) -> io::Result<usize> {
+        self.extend_from_slice(xs);
+        Ok(xs.len())
+    }
+
+    #[inline]
+    fn write_all(&mut self, xs: &[u8]) -> io::Result<()> {
+        self.extend_from_slice(xs);
+        Ok(())
+    }
+
+    #[inline]
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Drop for Buffer {
+    #[inline]
+    fn drop(&mut self) {
+        let b = self.take();
+        (b.drop)(b);
+    }
+}
+
+impl From<Vec<u8>> for Buffer {
+    fn from(mut v: Vec<u8>) -> Self {
+        let (data, len, capacity) = (v.as_mut_ptr(), v.len(), v.capacity());
+        mem::forget(v);
+
+        // This utility function is nested in here because it can *only*
+        // be safely called on `Buffer`s created by *this* `proc_macro`.
+        fn to_vec(b: Buffer) -> Vec<u8> {
+            unsafe {
+                let Buffer { data, len, capacity, .. } = b;
+                mem::forget(b);
+                Vec::from_raw_parts(data, len, capacity)
+            }
+        }
+
+        extern "C" fn reserve(b: Buffer, additional: usize) -> Buffer {
+            let mut v = to_vec(b);
+            v.reserve(additional);
+            Buffer::from(v)
+        }
+
+        extern "C" fn drop(b: Buffer) {
+            mem::drop(to_vec(b));
+        }
+
+        Buffer { data, len, capacity, reserve, drop }
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/client.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/client.rs
new file mode 100644
index 0000000000..22bda8ba5a
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/client.rs
@@ -0,0 +1,529 @@
+//! Client-side types.
+
+use super::*;
+
+use std::marker::PhantomData;
+
+macro_rules! define_handles {
+    (
+        'owned: $($oty:ident,)*
+        'interned: $($ity:ident,)*
+    ) => {
+        #[repr(C)]
+        #[allow(non_snake_case)]
+        pub struct HandleCounters {
+            $($oty: AtomicUsize,)*
+            $($ity: AtomicUsize,)*
+        }
+
+        impl HandleCounters {
+            // FIXME(eddyb) use a reference to the `static COUNTERS`, instead of
+            // a wrapper `fn` pointer, once `const fn` can reference `static`s.
+            extern "C" fn get() -> &'static Self {
+                static COUNTERS: HandleCounters = HandleCounters {
+                    $($oty: AtomicUsize::new(1),)*
+                    $($ity: AtomicUsize::new(1),)*
+                };
+                &COUNTERS
+            }
+        }
+
+        // FIXME(eddyb) generate the definition of `HandleStore` in `server.rs`.
+        #[repr(C)]
+        #[allow(non_snake_case)]
+        pub(super) struct HandleStore<S: server::Types> {
+            $($oty: handle::OwnedStore<S::$oty>,)*
+            $($ity: handle::InternedStore<S::$ity>,)*
+        }
+
+        impl<S: server::Types> HandleStore<S> {
+            pub(super) fn new(handle_counters: &'static HandleCounters) -> Self {
+                HandleStore {
+                    $($oty: handle::OwnedStore::new(&handle_counters.$oty),)*
+                    $($ity: handle::InternedStore::new(&handle_counters.$ity),)*
+                }
+            }
+        }
+
+        $(
+            #[repr(C)]
+            pub(crate) struct $oty {
+                handle: handle::Handle,
+                // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual
+                // way of doing this, but that requires unstable features.
+                // rust-analyzer uses this code and avoids unstable features.
+                _marker: PhantomData<*mut ()>,
+            }
+
+            // Forward `Drop::drop` to the inherent `drop` method.
+            impl Drop for $oty {
+                fn drop(&mut self) {
+                    $oty {
+                        handle: self.handle,
+                        _marker: PhantomData,
+                    }.drop();
+                }
+            }
+
+            impl<S> Encode<S> for $oty {
+                fn encode(self, w: &mut Writer, s: &mut S) {
+                    let handle = self.handle;
+                    mem::forget(self);
+                    handle.encode(w, s);
+                }
+            }
+
+            impl<S: server::Types> DecodeMut<'_, '_, HandleStore<server::MarkedTypes<S>>>
+                for Marked<S::$oty, $oty>
+            {
+                fn decode(r: &mut Reader<'_>, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
+                    s.$oty.take(handle::Handle::decode(r, &mut ()))
+                }
+            }
+
+            impl<S> Encode<S> for &$oty {
+                fn encode(self, w: &mut Writer, s: &mut S) {
+                    self.handle.encode(w, s);
+                }
+            }
+
+            impl<'s, S: server::Types> Decode<'_, 's, HandleStore<server::MarkedTypes<S>>>
+                for &'s Marked<S::$oty, $oty>
+            {
+                fn decode(r: &mut Reader<'_>, s: &'s HandleStore<server::MarkedTypes<S>>) -> Self {
+                    &s.$oty[handle::Handle::decode(r, &mut ())]
+                }
+            }
+
+            impl<S> Encode<S> for &mut $oty {
+                fn encode(self, w: &mut Writer, s: &mut S) {
+                    self.handle.encode(w, s);
+                }
+            }
+
+            impl<'s, S: server::Types> DecodeMut<'_, 's, HandleStore<server::MarkedTypes<S>>>
+                for &'s mut Marked<S::$oty, $oty>
+            {
+                fn decode(
+                    r: &mut Reader<'_>,
+                    s: &'s mut HandleStore<server::MarkedTypes<S>>
+                ) -> Self {
+                    &mut s.$oty[handle::Handle::decode(r, &mut ())]
+                }
+            }
+
+            impl<S: server::Types> Encode<HandleStore<server::MarkedTypes<S>>>
+                for Marked<S::$oty, $oty>
+            {
+                fn encode(self, w: &mut Writer, s: &mut HandleStore<server::MarkedTypes<S>>) {
+                    s.$oty.alloc(self).encode(w, s);
+                }
+            }
+
+            impl<S> DecodeMut<'_, '_, S> for $oty {
+                fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+                    $oty {
+                        handle: handle::Handle::decode(r, s),
+                        _marker: PhantomData,
+                    }
+                }
+            }
+        )*
+
+        $(
+            #[repr(C)]
+            #[derive(Copy, Clone, PartialEq, Eq, Hash)]
+            pub(crate) struct $ity {
+                handle: handle::Handle,
+                // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual
+                // way of doing this, but that requires unstable features.
+                // rust-analyzer uses this code and avoids unstable features.
+                _marker: PhantomData<*mut ()>,
+            }
+
+            impl<S> Encode<S> for $ity {
+                fn encode(self, w: &mut Writer, s: &mut S) {
+                    self.handle.encode(w, s);
+                }
+            }
+
+            impl<S: server::Types> DecodeMut<'_, '_, HandleStore<server::MarkedTypes<S>>>
+                for Marked<S::$ity, $ity>
+            {
+                fn decode(r: &mut Reader<'_>, s: &mut HandleStore<server::MarkedTypes<S>>) -> Self {
+                    s.$ity.copy(handle::Handle::decode(r, &mut ()))
+                }
+            }
+
+            impl<S: server::Types> Encode<HandleStore<server::MarkedTypes<S>>>
+                for Marked<S::$ity, $ity>
+            {
+                fn encode(self, w: &mut Writer, s: &mut HandleStore<server::MarkedTypes<S>>) {
+                    s.$ity.alloc(self).encode(w, s);
+                }
+            }
+
+            impl<S> DecodeMut<'_, '_, S> for $ity {
+                fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+                    $ity {
+                        handle: handle::Handle::decode(r, s),
+                        _marker: PhantomData,
+                    }
+                }
+            }
+        )*
+    }
+}
+define_handles! {
+    'owned:
+    FreeFunctions,
+    TokenStream,
+    Literal,
+    SourceFile,
+    MultiSpan,
+    Diagnostic,
+
+    'interned:
+    Ident,
+    Span,
+}
+
+// FIXME(eddyb) generate these impls by pattern-matching on the
+// names of methods - also could use the presence of `fn drop`
+// to distinguish between 'owned and 'interned, above.
+// Alternatively, special "modes" could be listed of types in with_api
+// instead of pattern matching on methods, here and in server decl.
+
+impl Clone for TokenStream {
+    fn clone(&self) -> Self {
+        self.clone()
+    }
+}
+
+impl Clone for Literal {
+    fn clone(&self) -> Self {
+        self.clone()
+    }
+}
+
+impl fmt::Debug for Literal {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Literal")
+            // format the kind without quotes, as in `kind: Float`
+            .field("kind", &format_args!("{}", &self.debug_kind()))
+            .field("symbol", &self.symbol())
+            // format `Some("...")` on one line even in {:#?} mode
+            .field("suffix", &format_args!("{:?}", &self.suffix()))
+            .field("span", &self.span())
+            .finish()
+    }
+}
+
+impl Clone for SourceFile {
+    fn clone(&self) -> Self {
+        self.clone()
+    }
+}
+
+impl Span {
+    pub(crate) fn def_site() -> Span {
+        Bridge::with(|bridge| bridge.globals.def_site)
+    }
+
+    pub(crate) fn call_site() -> Span {
+        Bridge::with(|bridge| bridge.globals.call_site)
+    }
+
+    pub(crate) fn mixed_site() -> Span {
+        Bridge::with(|bridge| bridge.globals.mixed_site)
+    }
+}
+
+impl fmt::Debug for Span {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.debug())
+    }
+}
+
+macro_rules! define_client_side {
+    ($($name:ident {
+        $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
+    }),* $(,)?) => {
+        $(impl $name {
+            $(pub(crate) fn $method($($arg: $arg_ty),*) $(-> $ret_ty)* {
+                Bridge::with(|bridge| {
+                    let mut buf = bridge.cached_buffer.take();
+
+                    buf.clear();
+                    api_tags::Method::$name(api_tags::$name::$method).encode(&mut buf, &mut ());
+                    reverse_encode!(buf; $($arg),*);
+
+                    buf = bridge.dispatch.call(buf);
+
+                    let r = Result::<_, PanicMessage>::decode(&mut &buf[..], &mut ());
+
+                    bridge.cached_buffer = buf;
+
+                    r.unwrap_or_else(|e| panic::resume_unwind(e.into()))
+                })
+            })*
+        })*
+    }
+}
+with_api!(self, self, define_client_side);
+
+struct Bridge<'a> {
+    /// Reusable buffer (only `clear`-ed, never shrunk), primarily
+    /// used for making requests.
+    cached_buffer: Buffer,
+
+    /// Server-side function that the client uses to make requests.
+    dispatch: closure::Closure<'a, Buffer, Buffer>,
+
+    /// Provided globals for this macro expansion.
+    globals: ExpnGlobals<Span>,
+}
+
+enum BridgeState<'a> {
+    /// No server is currently connected to this client.
+    NotConnected,
+
+    /// A server is connected and available for requests.
+    Connected(Bridge<'a>),
+
+    /// Access to the bridge is being exclusively acquired
+    /// (e.g., during `BridgeState::with`).
+    InUse,
+}
+
+enum BridgeStateL {}
+
+impl<'a> scoped_cell::ApplyL<'a> for BridgeStateL {
+    type Out = BridgeState<'a>;
+}
+
+thread_local! {
+    static BRIDGE_STATE: scoped_cell::ScopedCell<BridgeStateL> =
+        scoped_cell::ScopedCell::new(BridgeState::NotConnected);
+}
+
+impl BridgeState<'_> {
+    /// Take exclusive control of the thread-local
+    /// `BridgeState`, and pass it to `f`, mutably.
+    /// The state will be restored after `f` exits, even
+    /// by panic, including modifications made to it by `f`.
+    ///
+    /// N.B., while `f` is running, the thread-local state
+    /// is `BridgeState::InUse`.
+    fn with<R>(f: impl FnOnce(&mut BridgeState<'_>) -> R) -> R {
+        BRIDGE_STATE.with(|state| {
+            state.replace(BridgeState::InUse, |mut state| {
+                // FIXME(#52812) pass `f` directly to `replace` when `RefMutL` is gone
+                f(&mut *state)
+            })
+        })
+    }
+}
+
+impl Bridge<'_> {
+    fn with<R>(f: impl FnOnce(&mut Bridge<'_>) -> R) -> R {
+        BridgeState::with(|state| match state {
+            BridgeState::NotConnected => {
+                panic!("procedural macro API is used outside of a procedural macro");
+            }
+            BridgeState::InUse => {
+                panic!("procedural macro API is used while it's already in use");
+            }
+            BridgeState::Connected(bridge) => f(bridge),
+        })
+    }
+}
+
+pub(crate) fn is_available() -> bool {
+    BridgeState::with(|state| match state {
+        BridgeState::Connected(_) | BridgeState::InUse => true,
+        BridgeState::NotConnected => false,
+    })
+}
+
+/// A client-side RPC entry-point, which may be using a different `proc_macro`
+/// from the one used by the server, but can be invoked compatibly.
+///
+/// Note that the (phantom) `I` ("input") and `O` ("output") type parameters
+/// decorate the `Client<I, O>` with the RPC "interface" of the entry-point, but
+/// do not themselves participate in ABI, at all, only facilitate type-checking.
+///
+/// E.g. `Client<TokenStream, TokenStream>` is the common proc macro interface,
+/// used for `#[proc_macro] fn foo(input: TokenStream) -> TokenStream`,
+/// indicating that the RPC input and output will be serialized token streams,
+/// and forcing the use of APIs that take/return `S::TokenStream`, server-side.
+#[repr(C)]
+pub struct Client<I, O> {
+    // FIXME(eddyb) use a reference to the `static COUNTERS`, instead of
+    // a wrapper `fn` pointer, once `const fn` can reference `static`s.
+    pub(super) get_handle_counters: extern "C" fn() -> &'static HandleCounters,
+
+    pub(super) run: extern "C" fn(BridgeConfig<'_>) -> Buffer,
+
+    pub(super) _marker: PhantomData<fn(I) -> O>,
+}
+
+impl<I, O> Copy for Client<I, O> {}
+impl<I, O> Clone for Client<I, O> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+fn maybe_install_panic_hook(force_show_panics: bool) {
+    // Hide the default panic output within `proc_macro` expansions.
+    // NB. the server can't do this because it may use a different libstd.
+    static HIDE_PANICS_DURING_EXPANSION: Once = Once::new();
+    HIDE_PANICS_DURING_EXPANSION.call_once(|| {
+        let prev = panic::take_hook();
+        panic::set_hook(Box::new(move |info| {
+            let show = BridgeState::with(|state| match state {
+                BridgeState::NotConnected => true,
+                BridgeState::Connected(_) | BridgeState::InUse => force_show_panics,
+            });
+            if show {
+                prev(info)
+            }
+        }));
+    });
+}
+
+/// Client-side helper for handling client panics, entering the bridge,
+/// deserializing input and serializing output.
+// FIXME(eddyb) maybe replace `Bridge::enter` with this?
+fn run_client<A: for<'a, 's> DecodeMut<'a, 's, ()>, R: Encode<()>>(
+    config: BridgeConfig<'_>,
+    f: impl FnOnce(A) -> R,
+) -> Buffer {
+    let BridgeConfig { input: mut buf, dispatch, force_show_panics, .. } = config;
+
+    panic::catch_unwind(panic::AssertUnwindSafe(|| {
+        maybe_install_panic_hook(force_show_panics);
+
+        let reader = &mut &buf[..];
+        let (globals, input) = <(ExpnGlobals<Span>, A)>::decode(reader, &mut ());
+
+        // Put the buffer we used for input back in the `Bridge` for requests.
+        let new_state =
+            BridgeState::Connected(Bridge { cached_buffer: buf.take(), dispatch, globals });
+
+        BRIDGE_STATE.with(|state| {
+            state.set(new_state, || {
+                let output = f(input);
+
+                // Take the `cached_buffer` back out, for the output value.
+                buf = Bridge::with(|bridge| bridge.cached_buffer.take());
+
+                // HACK(eddyb) Separate encoding a success value (`Ok(output)`)
+                // from encoding a panic (`Err(e: PanicMessage)`) to avoid
+                // having handles outside the `bridge.enter(|| ...)` scope, and
+                // to catch panics that could happen while encoding the success.
+                //
+                // Note that panics should be impossible beyond this point, but
+                // this is defensively trying to avoid any accidental panicking
+                // reaching the `extern "C"` (which should `abort` but might not
+                // at the moment, so this is also potentially preventing UB).
+                buf.clear();
+                Ok::<_, ()>(output).encode(&mut buf, &mut ());
+            })
+        })
+    }))
+    .map_err(PanicMessage::from)
+    .unwrap_or_else(|e| {
+        buf.clear();
+        Err::<(), _>(e).encode(&mut buf, &mut ());
+    });
+    buf
+}
+
+impl Client<super::super::TokenStream, super::super::TokenStream> {
+    pub const fn expand1(
+        f: impl Fn(super::super::TokenStream) -> super::super::TokenStream + Copy,
+    ) -> Self {
+        Client {
+            get_handle_counters: HandleCounters::get,
+            run: super::selfless_reify::reify_to_extern_c_fn_hrt_bridge(move |bridge| {
+                run_client(bridge, |input| f(super::super::TokenStream(input)).0)
+            }),
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl Client<(super::super::TokenStream, super::super::TokenStream), super::super::TokenStream> {
+    pub const fn expand2(
+        f: impl Fn(super::super::TokenStream, super::super::TokenStream) -> super::super::TokenStream
+            + Copy,
+    ) -> Self {
+        Client {
+            get_handle_counters: HandleCounters::get,
+            run: super::selfless_reify::reify_to_extern_c_fn_hrt_bridge(move |bridge| {
+                run_client(bridge, |(input, input2)| {
+                    f(super::super::TokenStream(input), super::super::TokenStream(input2)).0
+                })
+            }),
+            _marker: PhantomData,
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Copy, Clone)]
+pub enum ProcMacro {
+    CustomDerive {
+        trait_name: &'static str,
+        attributes: &'static [&'static str],
+        client: Client<super::super::TokenStream, super::super::TokenStream>,
+    },
+
+    Attr {
+        name: &'static str,
+        client: Client<
+            (super::super::TokenStream, super::super::TokenStream),
+            super::super::TokenStream,
+        >,
+    },
+
+    Bang {
+        name: &'static str,
+        client: Client<super::super::TokenStream, super::super::TokenStream>,
+    },
+}
+
+impl ProcMacro {
+    pub fn name(&self) -> &'static str {
+        match self {
+            ProcMacro::CustomDerive { trait_name, .. } => trait_name,
+            ProcMacro::Attr { name, .. } => name,
+            ProcMacro::Bang { name, .. } => name,
+        }
+    }
+
+    pub const fn custom_derive(
+        trait_name: &'static str,
+        attributes: &'static [&'static str],
+        expand: impl Fn(super::super::TokenStream) -> super::super::TokenStream + Copy,
+    ) -> Self {
+        ProcMacro::CustomDerive { trait_name, attributes, client: Client::expand1(expand) }
+    }
+
+    pub const fn attr(
+        name: &'static str,
+        expand: impl Fn(super::super::TokenStream, super::super::TokenStream) -> super::super::TokenStream
+            + Copy,
+    ) -> Self {
+        ProcMacro::Attr { name, client: Client::expand2(expand) }
+    }
+
+    pub const fn bang(
+        name: &'static str,
+        expand: impl Fn(super::super::TokenStream) -> super::super::TokenStream + Copy,
+    ) -> Self {
+        ProcMacro::Bang { name, client: Client::expand1(expand) }
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/closure.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/closure.rs
new file mode 100644
index 0000000000..d371ae3cea
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/closure.rs
@@ -0,0 +1,32 @@
+//! Closure type (equivalent to `&mut dyn FnMut(A) -> R`) that's `repr(C)`.
+
+use std::marker::PhantomData;
+
+#[repr(C)]
+pub struct Closure<'a, A, R> {
+    call: unsafe extern "C" fn(*mut Env, A) -> R,
+    env: *mut Env,
+    // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual way of doing
+    // this, but that requires unstable features. rust-analyzer uses this code
+    // and avoids unstable features.
+    //
+    // The `'a` lifetime parameter represents the lifetime of `Env`.
+    _marker: PhantomData<*mut &'a mut ()>,
+}
+
+struct Env;
+
+impl<'a, A, R, F: FnMut(A) -> R> From<&'a mut F> for Closure<'a, A, R> {
+    fn from(f: &'a mut F) -> Self {
+        unsafe extern "C" fn call<A, R, F: FnMut(A) -> R>(env: *mut Env, arg: A) -> R {
+            (*(env as *mut _ as *mut F))(arg)
+        }
+        Closure { call: call::<A, R, F>, env: f as *mut _ as *mut Env, _marker: PhantomData }
+    }
+}
+
+impl<'a, A, R> Closure<'a, A, R> {
+    pub fn call(&mut self, arg: A) -> R {
+        unsafe { (self.call)(self.env, arg) }
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/handle.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/handle.rs
new file mode 100644
index 0000000000..c219a9465d
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/handle.rs
@@ -0,0 +1,89 @@
+//! Server-side handles and storage for per-handle data.
+
+use std::collections::{BTreeMap, HashMap};
+use std::hash::{BuildHasher, Hash};
+use std::num::NonZeroU32;
+use std::ops::{Index, IndexMut};
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+pub(super) type Handle = NonZeroU32;
+
+/// A store that associates values of type `T` with numeric handles. A value can
+/// be looked up using its handle.
+pub(super) struct OwnedStore<T: 'static> {
+    counter: &'static AtomicUsize,
+    data: BTreeMap<Handle, T>,
+}
+
+impl<T> OwnedStore<T> {
+    pub(super) fn new(counter: &'static AtomicUsize) -> Self {
+        // Ensure the handle counter isn't 0, which would panic later,
+        // when `NonZeroU32::new` (aka `Handle::new`) is called in `alloc`.
+        assert_ne!(counter.load(Ordering::SeqCst), 0);
+
+        OwnedStore { counter, data: BTreeMap::new() }
+    }
+}
+
+impl<T> OwnedStore<T> {
+    pub(super) fn alloc(&mut self, x: T) -> Handle {
+        let counter = self.counter.fetch_add(1, Ordering::SeqCst);
+        let handle = Handle::new(counter as u32).expect("`proc_macro` handle counter overflowed");
+        assert!(self.data.insert(handle, x).is_none());
+        handle
+    }
+
+    pub(super) fn take(&mut self, h: Handle) -> T {
+        self.data.remove(&h).expect("use-after-free in `proc_macro` handle")
+    }
+}
+
+impl<T> Index<Handle> for OwnedStore<T> {
+    type Output = T;
+    fn index(&self, h: Handle) -> &T {
+        self.data.get(&h).expect("use-after-free in `proc_macro` handle")
+    }
+}
+
+impl<T> IndexMut<Handle> for OwnedStore<T> {
+    fn index_mut(&mut self, h: Handle) -> &mut T {
+        self.data.get_mut(&h).expect("use-after-free in `proc_macro` handle")
+    }
+}
+
+// HACK(eddyb) deterministic `std::collections::hash_map::RandomState` replacement
+// that doesn't require adding any dependencies to `proc_macro` (like `rustc-hash`).
+#[derive(Clone)]
+struct NonRandomState;
+
+impl BuildHasher for NonRandomState {
+    type Hasher = std::collections::hash_map::DefaultHasher;
+    #[inline]
+    fn build_hasher(&self) -> Self::Hasher {
+        Self::Hasher::new()
+    }
+}
+
+/// Like `OwnedStore`, but avoids storing any value more than once.
+pub(super) struct InternedStore<T: 'static> {
+    owned: OwnedStore<T>,
+    interner: HashMap<T, Handle, NonRandomState>,
+}
+
+impl<T: Copy + Eq + Hash> InternedStore<T> {
+    pub(super) fn new(counter: &'static AtomicUsize) -> Self {
+        InternedStore {
+            owned: OwnedStore::new(counter),
+            interner: HashMap::with_hasher(NonRandomState),
+        }
+    }
+
+    pub(super) fn alloc(&mut self, x: T) -> Handle {
+        let owned = &mut self.owned;
+        *self.interner.entry(x).or_insert_with(|| owned.alloc(x))
+    }
+
+    pub(super) fn copy(&mut self, h: Handle) -> T {
+        self.owned[h]
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/mod.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/mod.rs
new file mode 100644
index 0000000000..ffd4407932
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/mod.rs
@@ -0,0 +1,493 @@
+//! Internal interface for communicating between a `proc_macro` client
+//! (a proc macro crate) and a `proc_macro` server (a compiler front-end).
+//!
+//! Serialization (with C ABI buffers) and unique integer handles are employed
+//! to allow safely interfacing between two copies of `proc_macro` built
+//! (from the same source) by different compilers with potentially mismatching
+//! Rust ABIs (e.g., stage0/bin/rustc vs stage1/bin/rustc during bootstrap).
+
+#![deny(unsafe_code)]
+
+pub use super::{Delimiter, Level, LineColumn, Spacing};
+use std::fmt;
+use std::hash::Hash;
+use std::marker;
+use std::mem;
+use std::ops::Bound;
+use std::panic;
+use std::sync::atomic::AtomicUsize;
+use std::sync::Once;
+use std::thread;
+
+/// Higher-order macro describing the server RPC API, allowing automatic
+/// generation of type-safe Rust APIs, both client-side and server-side.
+///
+/// `with_api!(MySelf, my_self, my_macro)` expands to:
+/// ```rust,ignore (pseudo-code)
+/// my_macro! {
+///     // ...
+///     Literal {
+///         // ...
+///         fn character(ch: char) -> MySelf::Literal;
+///         // ...
+///         fn span(my_self: &MySelf::Literal) -> MySelf::Span;
+///         fn set_span(my_self: &mut MySelf::Literal, span: MySelf::Span);
+///     },
+///     // ...
+/// }
+/// ```
+///
+/// The first two arguments serve to customize the arguments names
+/// and argument/return types, to enable several different usecases:
+///
+/// If `my_self` is just `self`, then each `fn` signature can be used
+/// as-is for a method. If it's anything else (`self_` in practice),
+/// then the signatures don't have a special `self` argument, and
+/// can, therefore, have a different one introduced.
+///
+/// If `MySelf` is just `Self`, then the types are only valid inside
+/// a trait or a trait impl, where the trait has associated types
+/// for each of the API types. If non-associated types are desired,
+/// a module name (`self` in practice) can be used instead of `Self`.
+macro_rules! with_api {
+    ($S:ident, $self:ident, $m:ident) => {
+        $m! {
+            FreeFunctions {
+                fn drop($self: $S::FreeFunctions);
+                fn track_env_var(var: &str, value: Option<&str>);
+                fn track_path(path: &str);
+            },
+            TokenStream {
+                fn drop($self: $S::TokenStream);
+                fn clone($self: &$S::TokenStream) -> $S::TokenStream;
+                fn is_empty($self: &$S::TokenStream) -> bool;
+                fn expand_expr($self: &$S::TokenStream) -> Result<$S::TokenStream, ()>;
+                fn from_str(src: &str) -> $S::TokenStream;
+                fn to_string($self: &$S::TokenStream) -> String;
+                fn from_token_tree(
+                    tree: TokenTree<$S::TokenStream, $S::Span, $S::Ident, $S::Literal>,
+                ) -> $S::TokenStream;
+                fn concat_trees(
+                    base: Option<$S::TokenStream>,
+                    trees: Vec<TokenTree<$S::TokenStream, $S::Span, $S::Ident, $S::Literal>>,
+                ) -> $S::TokenStream;
+                fn concat_streams(
+                    base: Option<$S::TokenStream>,
+                    streams: Vec<$S::TokenStream>,
+                ) -> $S::TokenStream;
+                fn into_trees(
+                    $self: $S::TokenStream
+                ) -> Vec<TokenTree<$S::TokenStream, $S::Span, $S::Ident, $S::Literal>>;
+            },
+            Ident {
+                fn new(string: &str, span: $S::Span, is_raw: bool) -> $S::Ident;
+                fn span($self: $S::Ident) -> $S::Span;
+                fn with_span($self: $S::Ident, span: $S::Span) -> $S::Ident;
+            },
+            Literal {
+                fn drop($self: $S::Literal);
+                fn clone($self: &$S::Literal) -> $S::Literal;
+                fn from_str(s: &str) -> Result<$S::Literal, ()>;
+                fn to_string($self: &$S::Literal) -> String;
+                fn debug_kind($self: &$S::Literal) -> String;
+                fn symbol($self: &$S::Literal) -> String;
+                fn suffix($self: &$S::Literal) -> Option<String>;
+                fn integer(n: &str) -> $S::Literal;
+                fn typed_integer(n: &str, kind: &str) -> $S::Literal;
+                fn float(n: &str) -> $S::Literal;
+                fn f32(n: &str) -> $S::Literal;
+                fn f64(n: &str) -> $S::Literal;
+                fn string(string: &str) -> $S::Literal;
+                fn character(ch: char) -> $S::Literal;
+                fn byte_string(bytes: &[u8]) -> $S::Literal;
+                fn span($self: &$S::Literal) -> $S::Span;
+                fn set_span($self: &mut $S::Literal, span: $S::Span);
+                fn subspan(
+                    $self: &$S::Literal,
+                    start: Bound<usize>,
+                    end: Bound<usize>,
+                ) -> Option<$S::Span>;
+            },
+            SourceFile {
+                fn drop($self: $S::SourceFile);
+                fn clone($self: &$S::SourceFile) -> $S::SourceFile;
+                fn eq($self: &$S::SourceFile, other: &$S::SourceFile) -> bool;
+                fn path($self: &$S::SourceFile) -> String;
+                fn is_real($self: &$S::SourceFile) -> bool;
+            },
+            MultiSpan {
+                fn drop($self: $S::MultiSpan);
+                fn new() -> $S::MultiSpan;
+                fn push($self: &mut $S::MultiSpan, span: $S::Span);
+            },
+            Diagnostic {
+                fn drop($self: $S::Diagnostic);
+                fn new(level: Level, msg: &str, span: $S::MultiSpan) -> $S::Diagnostic;
+                fn sub(
+                    $self: &mut $S::Diagnostic,
+                    level: Level,
+                    msg: &str,
+                    span: $S::MultiSpan,
+                );
+                fn emit($self: $S::Diagnostic);
+            },
+            Span {
+                fn debug($self: $S::Span) -> String;
+                fn source_file($self: $S::Span) -> $S::SourceFile;
+                fn parent($self: $S::Span) -> Option<$S::Span>;
+                fn source($self: $S::Span) -> $S::Span;
+                fn start($self: $S::Span) -> LineColumn;
+                fn end($self: $S::Span) -> LineColumn;
+                fn before($self: $S::Span) -> $S::Span;
+                fn after($self: $S::Span) -> $S::Span;
+                fn join($self: $S::Span, other: $S::Span) -> Option<$S::Span>;
+                fn resolved_at($self: $S::Span, at: $S::Span) -> $S::Span;
+                fn source_text($self: $S::Span) -> Option<String>;
+                fn save_span($self: $S::Span) -> usize;
+                fn recover_proc_macro_span(id: usize) -> $S::Span;
+            },
+        }
+    };
+}
+
+// FIXME(eddyb) this calls `encode` for each argument, but in reverse,
+// to match the ordering in `reverse_decode`.
+macro_rules! reverse_encode {
+    ($writer:ident;) => {};
+    ($writer:ident; $first:ident $(, $rest:ident)*) => {
+        reverse_encode!($writer; $($rest),*);
+        $first.encode(&mut $writer, &mut ());
+    }
+}
+
+// FIXME(eddyb) this calls `decode` for each argument, but in reverse,
+// to avoid borrow conflicts from borrows started by `&mut` arguments.
+macro_rules! reverse_decode {
+    ($reader:ident, $s:ident;) => {};
+    ($reader:ident, $s:ident; $first:ident: $first_ty:ty $(, $rest:ident: $rest_ty:ty)*) => {
+        reverse_decode!($reader, $s; $($rest: $rest_ty),*);
+        let $first = <$first_ty>::decode(&mut $reader, $s);
+    }
+}
+
+#[allow(unsafe_code)]
+mod buffer;
+#[forbid(unsafe_code)]
+pub mod client;
+#[allow(unsafe_code)]
+mod closure;
+#[forbid(unsafe_code)]
+mod handle;
+#[macro_use]
+#[forbid(unsafe_code)]
+mod rpc;
+#[allow(unsafe_code)]
+mod scoped_cell;
+#[allow(unsafe_code)]
+mod selfless_reify;
+#[forbid(unsafe_code)]
+pub mod server;
+
+use buffer::Buffer;
+pub use rpc::PanicMessage;
+use rpc::{Decode, DecodeMut, Encode, Reader, Writer};
+
+/// Configuration for establishing an active connection between a server and a
+/// client.  The server creates the bridge config (`run_server` in `server.rs`),
+/// then passes it to the client through the function pointer in the `run` field
+/// of `client::Client`. The client constructs a local `Bridge` from the config
+/// in TLS during its execution (`Bridge::{enter, with}` in `client.rs`).
+#[repr(C)]
+pub struct BridgeConfig<'a> {
+    /// Buffer used to pass initial input to the client.
+    input: Buffer,
+
+    /// Server-side function that the client uses to make requests.
+    dispatch: closure::Closure<'a, Buffer, Buffer>,
+
+    /// If 'true', always invoke the default panic hook
+    force_show_panics: bool,
+
+    // Prevent Send and Sync impls. `!Send`/`!Sync` is the usual way of doing
+    // this, but that requires unstable features. rust-analyzer uses this code
+    // and avoids unstable features.
+    _marker: marker::PhantomData<*mut ()>,
+}
+
+#[forbid(unsafe_code)]
+#[allow(non_camel_case_types)]
+mod api_tags {
+    use super::rpc::{DecodeMut, Encode, Reader, Writer};
+
+    macro_rules! declare_tags {
+        ($($name:ident {
+            $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)*;)*
+        }),* $(,)?) => {
+            $(
+                pub(super) enum $name {
+                    $($method),*
+                }
+                rpc_encode_decode!(enum $name { $($method),* });
+            )*
+
+            pub(super) enum Method {
+                $($name($name)),*
+            }
+            rpc_encode_decode!(enum Method { $($name(m)),* });
+        }
+    }
+    with_api!(self, self, declare_tags);
+}
+
+/// Helper to wrap associated types to allow trait impl dispatch.
+/// That is, normally a pair of impls for `T::Foo` and `T::Bar`
+/// can overlap, but if the impls are, instead, on types like
+/// `Marked<T::Foo, Foo>` and `Marked<T::Bar, Bar>`, they can't.
+trait Mark {
+    type Unmarked;
+    fn mark(unmarked: Self::Unmarked) -> Self;
+}
+
+/// Unwrap types wrapped by `Mark::mark` (see `Mark` for details).
+trait Unmark {
+    type Unmarked;
+    fn unmark(self) -> Self::Unmarked;
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, Hash)]
+struct Marked<T, M> {
+    value: T,
+    _marker: marker::PhantomData<M>,
+}
+
+impl<T, M> Mark for Marked<T, M> {
+    type Unmarked = T;
+    fn mark(unmarked: Self::Unmarked) -> Self {
+        Marked { value: unmarked, _marker: marker::PhantomData }
+    }
+}
+impl<T, M> Unmark for Marked<T, M> {
+    type Unmarked = T;
+    fn unmark(self) -> Self::Unmarked {
+        self.value
+    }
+}
+impl<'a, T, M> Unmark for &'a Marked<T, M> {
+    type Unmarked = &'a T;
+    fn unmark(self) -> Self::Unmarked {
+        &self.value
+    }
+}
+impl<'a, T, M> Unmark for &'a mut Marked<T, M> {
+    type Unmarked = &'a mut T;
+    fn unmark(self) -> Self::Unmarked {
+        &mut self.value
+    }
+}
+
+impl<T: Mark> Mark for Vec<T> {
+    type Unmarked = Vec<T::Unmarked>;
+    fn mark(unmarked: Self::Unmarked) -> Self {
+        // Should be a no-op due to std's in-place collect optimizations.
+        unmarked.into_iter().map(T::mark).collect()
+    }
+}
+impl<T: Unmark> Unmark for Vec<T> {
+    type Unmarked = Vec<T::Unmarked>;
+    fn unmark(self) -> Self::Unmarked {
+        // Should be a no-op due to std's in-place collect optimizations.
+        self.into_iter().map(T::unmark).collect()
+    }
+}
+
+macro_rules! mark_noop {
+    ($($ty:ty),* $(,)?) => {
+        $(
+            impl Mark for $ty {
+                type Unmarked = Self;
+                fn mark(unmarked: Self::Unmarked) -> Self {
+                    unmarked
+                }
+            }
+            impl Unmark for $ty {
+                type Unmarked = Self;
+                fn unmark(self) -> Self::Unmarked {
+                    self
+                }
+            }
+        )*
+    }
+}
+mark_noop! {
+    (),
+    bool,
+    char,
+    &'_ [u8],
+    &'_ str,
+    String,
+    u8,
+    usize,
+    Delimiter,
+    Level,
+    LineColumn,
+    Spacing,
+}
+
+rpc_encode_decode!(
+    enum Delimiter {
+        Parenthesis,
+        Brace,
+        Bracket,
+        None,
+    }
+);
+rpc_encode_decode!(
+    enum Level {
+        Error,
+        Warning,
+        Note,
+        Help,
+    }
+);
+rpc_encode_decode!(struct LineColumn { line, column });
+rpc_encode_decode!(
+    enum Spacing {
+        Alone,
+        Joint,
+    }
+);
+
+macro_rules! mark_compound {
+    (struct $name:ident <$($T:ident),+> { $($field:ident),* $(,)? }) => {
+        impl<$($T: Mark),+> Mark for $name <$($T),+> {
+            type Unmarked = $name <$($T::Unmarked),+>;
+            fn mark(unmarked: Self::Unmarked) -> Self {
+                $name {
+                    $($field: Mark::mark(unmarked.$field)),*
+                }
+            }
+        }
+        impl<$($T: Unmark),+> Unmark for $name <$($T),+> {
+            type Unmarked = $name <$($T::Unmarked),+>;
+            fn unmark(self) -> Self::Unmarked {
+                $name {
+                    $($field: Unmark::unmark(self.$field)),*
+                }
+            }
+        }
+    };
+    (enum $name:ident <$($T:ident),+> { $($variant:ident $(($field:ident))?),* $(,)? }) => {
+        impl<$($T: Mark),+> Mark for $name <$($T),+> {
+            type Unmarked = $name <$($T::Unmarked),+>;
+            fn mark(unmarked: Self::Unmarked) -> Self {
+                match unmarked {
+                    $($name::$variant $(($field))? => {
+                        $name::$variant $((Mark::mark($field)))?
+                    })*
+                }
+            }
+        }
+        impl<$($T: Unmark),+> Unmark for $name <$($T),+> {
+            type Unmarked = $name <$($T::Unmarked),+>;
+            fn unmark(self) -> Self::Unmarked {
+                match self {
+                    $($name::$variant $(($field))? => {
+                        $name::$variant $((Unmark::unmark($field)))?
+                    })*
+                }
+            }
+        }
+    }
+}
+
+macro_rules! compound_traits {
+    ($($t:tt)*) => {
+        rpc_encode_decode!($($t)*);
+        mark_compound!($($t)*);
+    };
+}
+
+compound_traits!(
+    enum Bound<T> {
+        Included(x),
+        Excluded(x),
+        Unbounded,
+    }
+);
+
+compound_traits!(
+    enum Option<T> {
+        Some(t),
+        None,
+    }
+);
+
+compound_traits!(
+    enum Result<T, E> {
+        Ok(t),
+        Err(e),
+    }
+);
+
+#[derive(Copy, Clone)]
+pub struct DelimSpan<Span> {
+    pub open: Span,
+    pub close: Span,
+    pub entire: Span,
+}
+
+impl<Span: Copy> DelimSpan<Span> {
+    pub fn from_single(span: Span) -> Self {
+        DelimSpan { open: span, close: span, entire: span }
+    }
+}
+
+compound_traits!(struct DelimSpan<Span> { open, close, entire });
+
+#[derive(Clone)]
+pub struct Group<TokenStream, Span> {
+    pub delimiter: Delimiter,
+    pub stream: Option<TokenStream>,
+    pub span: DelimSpan<Span>,
+}
+
+compound_traits!(struct Group<TokenStream, Span> { delimiter, stream, span });
+
+#[derive(Clone)]
+pub struct Punct<Span> {
+    pub ch: u8,
+    pub joint: bool,
+    pub span: Span,
+}
+
+compound_traits!(struct Punct<Span> { ch, joint, span });
+
+#[derive(Clone)]
+pub enum TokenTree<TokenStream, Span, Ident, Literal> {
+    Group(Group<TokenStream, Span>),
+    Punct(Punct<Span>),
+    Ident(Ident),
+    Literal(Literal),
+}
+
+compound_traits!(
+    enum TokenTree<TokenStream, Span, Ident, Literal> {
+        Group(tt),
+        Punct(tt),
+        Ident(tt),
+        Literal(tt),
+    }
+);
+
+/// Globals provided alongside the initial inputs for a macro expansion.
+/// Provides values such as spans which are used frequently to avoid RPC.
+#[derive(Clone)]
+pub struct ExpnGlobals<Span> {
+    pub def_site: Span,
+    pub call_site: Span,
+    pub mixed_site: Span,
+}
+
+compound_traits!(
+    struct ExpnGlobals<Span> { def_site, call_site, mixed_site }
+);
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/rpc.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/rpc.rs
new file mode 100644
index 0000000000..e9d7a46c06
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/rpc.rs
@@ -0,0 +1,304 @@
+//! Serialization for client-server communication.
+
+use std::any::Any;
+use std::char;
+use std::io::Write;
+use std::num::NonZeroU32;
+use std::str;
+
+pub(super) type Writer = super::buffer::Buffer;
+
+pub(super) trait Encode<S>: Sized {
+    fn encode(self, w: &mut Writer, s: &mut S);
+}
+
+pub(super) type Reader<'a> = &'a [u8];
+
+pub(super) trait Decode<'a, 's, S>: Sized {
+    fn decode(r: &mut Reader<'a>, s: &'s S) -> Self;
+}
+
+pub(super) trait DecodeMut<'a, 's, S>: Sized {
+    fn decode(r: &mut Reader<'a>, s: &'s mut S) -> Self;
+}
+
+macro_rules! rpc_encode_decode {
+    (le $ty:ty) => {
+        impl<S> Encode<S> for $ty {
+            fn encode(self, w: &mut Writer, _: &mut S) {
+                w.extend_from_array(&self.to_le_bytes());
+            }
+        }
+
+        impl<S> DecodeMut<'_, '_, S> for $ty {
+            fn decode(r: &mut Reader<'_>, _: &mut S) -> Self {
+                const N: usize = ::std::mem::size_of::<$ty>();
+
+                let mut bytes = [0; N];
+                bytes.copy_from_slice(&r[..N]);
+                *r = &r[N..];
+
+                Self::from_le_bytes(bytes)
+            }
+        }
+    };
+    (struct $name:ident $(<$($T:ident),+>)? { $($field:ident),* $(,)? }) => {
+        impl<S, $($($T: Encode<S>),+)?> Encode<S> for $name $(<$($T),+>)? {
+            fn encode(self, w: &mut Writer, s: &mut S) {
+                $(self.$field.encode(w, s);)*
+            }
+        }
+
+        impl<'a, S, $($($T: for<'s> DecodeMut<'a, 's, S>),+)?> DecodeMut<'a, '_, S>
+            for $name $(<$($T),+>)?
+        {
+            fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
+                $name {
+                    $($field: DecodeMut::decode(r, s)),*
+                }
+            }
+        }
+    };
+    (enum $name:ident $(<$($T:ident),+>)? { $($variant:ident $(($field:ident))*),* $(,)? }) => {
+        impl<S, $($($T: Encode<S>),+)?> Encode<S> for $name $(<$($T),+>)? {
+            fn encode(self, w: &mut Writer, s: &mut S) {
+                // HACK(eddyb): `Tag` enum duplicated between the
+                // two impls as there's no other place to stash it.
+                #[allow(non_upper_case_globals)]
+                mod tag {
+                    #[repr(u8)] enum Tag { $($variant),* }
+
+                    $(pub const $variant: u8 = Tag::$variant as u8;)*
+                }
+
+                match self {
+                    $($name::$variant $(($field))* => {
+                        tag::$variant.encode(w, s);
+                        $($field.encode(w, s);)*
+                    })*
+                }
+            }
+        }
+
+        impl<'a, S, $($($T: for<'s> DecodeMut<'a, 's, S>),+)?> DecodeMut<'a, '_, S>
+            for $name $(<$($T),+>)?
+        {
+            fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
+                // HACK(eddyb): `Tag` enum duplicated between the
+                // two impls as there's no other place to stash it.
+                #[allow(non_upper_case_globals)]
+                mod tag {
+                    #[repr(u8)] enum Tag { $($variant),* }
+
+                    $(pub const $variant: u8 = Tag::$variant as u8;)*
+                }
+
+                match u8::decode(r, s) {
+                    $(tag::$variant => {
+                        $(let $field = DecodeMut::decode(r, s);)*
+                        $name::$variant $(($field))*
+                    })*
+                    _ => unreachable!(),
+                }
+            }
+        }
+    }
+}
+
+impl<S> Encode<S> for () {
+    fn encode(self, _: &mut Writer, _: &mut S) {}
+}
+
+impl<S> DecodeMut<'_, '_, S> for () {
+    fn decode(_: &mut Reader<'_>, _: &mut S) -> Self {}
+}
+
+impl<S> Encode<S> for u8 {
+    fn encode(self, w: &mut Writer, _: &mut S) {
+        w.push(self);
+    }
+}
+
+impl<S> DecodeMut<'_, '_, S> for u8 {
+    fn decode(r: &mut Reader<'_>, _: &mut S) -> Self {
+        let x = r[0];
+        *r = &r[1..];
+        x
+    }
+}
+
+rpc_encode_decode!(le u32);
+rpc_encode_decode!(le usize);
+
+impl<S> Encode<S> for bool {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        (self as u8).encode(w, s);
+    }
+}
+
+impl<S> DecodeMut<'_, '_, S> for bool {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+        match u8::decode(r, s) {
+            0 => false,
+            1 => true,
+            _ => unreachable!(),
+        }
+    }
+}
+
+impl<S> Encode<S> for char {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        (self as u32).encode(w, s);
+    }
+}
+
+impl<S> DecodeMut<'_, '_, S> for char {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+        char::from_u32(u32::decode(r, s)).unwrap()
+    }
+}
+
+impl<S> Encode<S> for NonZeroU32 {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self.get().encode(w, s);
+    }
+}
+
+impl<S> DecodeMut<'_, '_, S> for NonZeroU32 {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+        Self::new(u32::decode(r, s)).unwrap()
+    }
+}
+
+impl<S, A: Encode<S>, B: Encode<S>> Encode<S> for (A, B) {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self.0.encode(w, s);
+        self.1.encode(w, s);
+    }
+}
+
+impl<'a, S, A: for<'s> DecodeMut<'a, 's, S>, B: for<'s> DecodeMut<'a, 's, S>> DecodeMut<'a, '_, S>
+    for (A, B)
+{
+    fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
+        (DecodeMut::decode(r, s), DecodeMut::decode(r, s))
+    }
+}
+
+impl<S> Encode<S> for &[u8] {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self.len().encode(w, s);
+        w.write_all(self).unwrap();
+    }
+}
+
+impl<'a, S> DecodeMut<'a, '_, S> for &'a [u8] {
+    fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
+        let len = usize::decode(r, s);
+        let xs = &r[..len];
+        *r = &r[len..];
+        xs
+    }
+}
+
+impl<S> Encode<S> for &str {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self.as_bytes().encode(w, s);
+    }
+}
+
+impl<'a, S> DecodeMut<'a, '_, S> for &'a str {
+    fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
+        str::from_utf8(<&[u8]>::decode(r, s)).unwrap()
+    }
+}
+
+impl<S> Encode<S> for String {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self[..].encode(w, s);
+    }
+}
+
+impl<S> DecodeMut<'_, '_, S> for String {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+        <&str>::decode(r, s).to_string()
+    }
+}
+
+impl<S, T: Encode<S>> Encode<S> for Vec<T> {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self.len().encode(w, s);
+        for x in self {
+            x.encode(w, s);
+        }
+    }
+}
+
+impl<'a, S, T: for<'s> DecodeMut<'a, 's, S>> DecodeMut<'a, '_, S> for Vec<T> {
+    fn decode(r: &mut Reader<'a>, s: &mut S) -> Self {
+        let len = usize::decode(r, s);
+        let mut vec = Vec::with_capacity(len);
+        for _ in 0..len {
+            vec.push(T::decode(r, s));
+        }
+        vec
+    }
+}
+
+/// Simplified version of panic payloads, ignoring
+/// types other than `&'static str` and `String`.
+pub enum PanicMessage {
+    StaticStr(&'static str),
+    String(String),
+    Unknown,
+}
+
+impl From<Box<dyn Any + Send>> for PanicMessage {
+    fn from(payload: Box<dyn Any + Send + 'static>) -> Self {
+        if let Some(s) = payload.downcast_ref::<&'static str>() {
+            return PanicMessage::StaticStr(s);
+        }
+        if let Ok(s) = payload.downcast::<String>() {
+            return PanicMessage::String(*s);
+        }
+        PanicMessage::Unknown
+    }
+}
+
+impl Into<Box<dyn Any + Send>> for PanicMessage {
+    fn into(self) -> Box<dyn Any + Send> {
+        match self {
+            PanicMessage::StaticStr(s) => Box::new(s),
+            PanicMessage::String(s) => Box::new(s),
+            PanicMessage::Unknown => {
+                struct UnknownPanicMessage;
+                Box::new(UnknownPanicMessage)
+            }
+        }
+    }
+}
+
+impl PanicMessage {
+    pub fn as_str(&self) -> Option<&str> {
+        match self {
+            PanicMessage::StaticStr(s) => Some(s),
+            PanicMessage::String(s) => Some(s),
+            PanicMessage::Unknown => None,
+        }
+    }
+}
+
+impl<S> Encode<S> for PanicMessage {
+    fn encode(self, w: &mut Writer, s: &mut S) {
+        self.as_str().encode(w, s);
+    }
+}
+
+impl<S> DecodeMut<'_, '_, S> for PanicMessage {
+    fn decode(r: &mut Reader<'_>, s: &mut S) -> Self {
+        match Option::<String>::decode(r, s) {
+            Some(s) => PanicMessage::String(s),
+            None => PanicMessage::Unknown,
+        }
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/scoped_cell.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/scoped_cell.rs
new file mode 100644
index 0000000000..2cde1f65ad
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/scoped_cell.rs
@@ -0,0 +1,81 @@
+//! `Cell` variant for (scoped) existential lifetimes.
+
+use std::cell::Cell;
+use std::mem;
+use std::ops::{Deref, DerefMut};
+
+/// Type lambda application, with a lifetime.
+#[allow(unused_lifetimes)]
+pub trait ApplyL<'a> {
+    type Out;
+}
+
+/// Type lambda taking a lifetime, i.e., `Lifetime -> Type`.
+pub trait LambdaL: for<'a> ApplyL<'a> {}
+
+impl<T: for<'a> ApplyL<'a>> LambdaL for T {}
+
+// HACK(eddyb) work around projection limitations with a newtype
+// FIXME(#52812) replace with `&'a mut <T as ApplyL<'b>>::Out`
+pub struct RefMutL<'a, 'b, T: LambdaL>(&'a mut <T as ApplyL<'b>>::Out);
+
+impl<'a, 'b, T: LambdaL> Deref for RefMutL<'a, 'b, T> {
+    type Target = <T as ApplyL<'b>>::Out;
+    fn deref(&self) -> &Self::Target {
+        self.0
+    }
+}
+
+impl<'a, 'b, T: LambdaL> DerefMut for RefMutL<'a, 'b, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.0
+    }
+}
+
+pub struct ScopedCell<T: LambdaL>(Cell<<T as ApplyL<'static>>::Out>);
+
+impl<T: LambdaL> ScopedCell<T> {
+    pub const fn new(value: <T as ApplyL<'static>>::Out) -> Self {
+        ScopedCell(Cell::new(value))
+    }
+
+    /// Sets the value in `self` to `replacement` while
+    /// running `f`, which gets the old value, mutably.
+    /// The old value will be restored after `f` exits, even
+    /// by panic, including modifications made to it by `f`.
+    pub fn replace<'a, R>(
+        &self,
+        replacement: <T as ApplyL<'a>>::Out,
+        f: impl for<'b, 'c> FnOnce(RefMutL<'b, 'c, T>) -> R,
+    ) -> R {
+        /// Wrapper that ensures that the cell always gets filled
+        /// (with the original state, optionally changed by `f`),
+        /// even if `f` had panicked.
+        struct PutBackOnDrop<'a, T: LambdaL> {
+            cell: &'a ScopedCell<T>,
+            value: Option<<T as ApplyL<'static>>::Out>,
+        }
+
+        impl<'a, T: LambdaL> Drop for PutBackOnDrop<'a, T> {
+            fn drop(&mut self) {
+                self.cell.0.set(self.value.take().unwrap());
+            }
+        }
+
+        let mut put_back_on_drop = PutBackOnDrop {
+            cell: self,
+            value: Some(self.0.replace(unsafe {
+                let erased = mem::transmute_copy(&replacement);
+                mem::forget(replacement);
+                erased
+            })),
+        };
+
+        f(RefMutL(put_back_on_drop.value.as_mut().unwrap()))
+    }
+
+    /// Sets the value in `self` to `value` while running `f`.
+    pub fn set<R>(&self, value: <T as ApplyL<'_>>::Out, f: impl FnOnce() -> R) -> R {
+        self.replace(value, |_| f())
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/selfless_reify.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/selfless_reify.rs
new file mode 100644
index 0000000000..907ad256e4
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/selfless_reify.rs
@@ -0,0 +1,84 @@
+//! Abstraction for creating `fn` pointers from any callable that *effectively*
+//! has the equivalent of implementing `Default`, even if the compiler neither
+//! provides `Default` nor allows reifying closures (i.e. creating `fn` pointers)
+//! other than those with absolutely no captures.
+//!
+//! More specifically, for a closure-like type to be "effectively `Default`":
+//! * it must be a ZST (zero-sized type): no information contained within, so
+//!   that `Default`'s return value (if it were implemented) is unambiguous
+//! * it must be `Copy`: no captured "unique ZST tokens" or any other similar
+//!   types that would make duplicating values at will unsound
+//!   * combined with the ZST requirement, this confers a kind of "telecopy"
+//!     ability: similar to `Copy`, but without keeping the value around, and
+//!     instead "reconstructing" it (a noop given it's a ZST) when needed
+//! * it must be *provably* inhabited: no captured uninhabited types or any
+//!   other types that cannot be constructed by the user of this abstraction
+//!   * the proof is a value of the closure-like type itself, in a sense the
+//!     "seed" for the "telecopy" process made possible by ZST + `Copy`
+//!   * this requirement is the only reason an abstraction limited to a specific
+//!     usecase is required: ZST + `Copy` can be checked with *at worst* a panic
+//!     at the "attempted `::default()` call" time, but that doesn't guarantee
+//!     that the value can be soundly created, and attempting to use the typical
+//!     "proof ZST token" approach leads yet again to having a ZST + `Copy` type
+//!     that is not proof of anything without a value (i.e. isomorphic to a
+//!     newtype of the type it's trying to prove the inhabitation of)
+//!
+//! A more flexible (and safer) solution to the general problem could exist once
+//! `const`-generic parameters can have type parameters in their types:
+//!
+//! ```rust,ignore (needs future const-generics)
+//! extern "C" fn ffi_wrapper<
+//!     A, R,
+//!     F: Fn(A) -> R,
+//!     const f: F, // <-- this `const`-generic is not yet allowed
+//! >(arg: A) -> R {
+//!     f(arg)
+//! }
+//! ```
+
+use std::mem;
+
+// FIXME(eddyb) this could be `trait` impls except for the `const fn` requirement.
+macro_rules! define_reify_functions {
+    ($(
+        fn $name:ident $(<$($param:ident),*>)?
+            for $(extern $abi:tt)? fn($($arg:ident: $arg_ty:ty),*) -> $ret_ty:ty;
+    )+) => {
+        $(pub const fn $name<
+            $($($param,)*)?
+            F: Fn($($arg_ty),*) -> $ret_ty + Copy
+        >(f: F) -> $(extern $abi)? fn($($arg_ty),*) -> $ret_ty {
+            // FIXME(eddyb) describe the `F` type (e.g. via `type_name::<F>`) once panic
+            // formatting becomes possible in `const fn`.
+            assert!(mem::size_of::<F>() == 0, "selfless_reify: closure must be zero-sized");
+
+            $(extern $abi)? fn wrapper<
+                $($($param,)*)?
+                F: Fn($($arg_ty),*) -> $ret_ty + Copy
+            >($($arg: $arg_ty),*) -> $ret_ty {
+                let f = unsafe {
+                    // SAFETY: `F` satisfies all criteria for "out of thin air"
+                    // reconstructability (see module-level doc comment).
+                    mem::MaybeUninit::<F>::uninit().assume_init()
+                };
+                f($($arg),*)
+            }
+            let _f_proof = f;
+            wrapper::<
+                $($($param,)*)?
+                F
+            >
+        })+
+    }
+}
+
+define_reify_functions! {
+    fn _reify_to_extern_c_fn_unary<A, R> for extern "C" fn(arg: A) -> R;
+
+    // HACK(eddyb) this abstraction is used with `for<'a> fn(BridgeConfig<'a>)
+    // -> T` but that doesn't work with just `reify_to_extern_c_fn_unary`
+    // because of the `fn` pointer type being "higher-ranked" (i.e. the
+    // `for<'a>` binder).
+    // FIXME(eddyb) try to remove the lifetime from `BridgeConfig`, that'd help.
+    fn reify_to_extern_c_fn_hrt_bridge<R> for extern "C" fn(bridge: super::BridgeConfig<'_>) -> R;
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/server.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/server.rs
new file mode 100644
index 0000000000..6e7a8d8c10
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/bridge/server.rs
@@ -0,0 +1,339 @@
+//! Server-side traits.
+
+use super::*;
+
+// FIXME(eddyb) generate the definition of `HandleStore` in `server.rs`.
+use super::client::HandleStore;
+
+pub trait Types {
+    type FreeFunctions: 'static;
+    type TokenStream: 'static + Clone;
+    type Ident: 'static + Copy + Eq + Hash;
+    type Literal: 'static + Clone;
+    type SourceFile: 'static + Clone;
+    type MultiSpan: 'static;
+    type Diagnostic: 'static;
+    type Span: 'static + Copy + Eq + Hash;
+}
+
+/// Declare an associated fn of one of the traits below, adding necessary
+/// default bodies.
+macro_rules! associated_fn {
+    (fn drop(&mut self, $arg:ident: $arg_ty:ty)) =>
+        (fn drop(&mut self, $arg: $arg_ty) { mem::drop($arg) });
+
+    (fn clone(&mut self, $arg:ident: $arg_ty:ty) -> $ret_ty:ty) =>
+        (fn clone(&mut self, $arg: $arg_ty) -> $ret_ty { $arg.clone() });
+
+    ($($item:tt)*) => ($($item)*;)
+}
+
+macro_rules! declare_server_traits {
+    ($($name:ident {
+        $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
+    }),* $(,)?) => {
+        $(pub trait $name: Types {
+            $(associated_fn!(fn $method(&mut self, $($arg: $arg_ty),*) $(-> $ret_ty)?);)*
+        })*
+
+        pub trait Server: Types $(+ $name)* {
+            fn globals(&mut self) -> ExpnGlobals<Self::Span>;
+        }
+    }
+}
+with_api!(Self, self_, declare_server_traits);
+
+pub(super) struct MarkedTypes<S: Types>(S);
+
+impl<S: Server> Server for MarkedTypes<S> {
+    fn globals(&mut self) -> ExpnGlobals<Self::Span> {
+        <_>::mark(Server::globals(&mut self.0))
+    }
+}
+
+macro_rules! define_mark_types_impls {
+    ($($name:ident {
+        $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
+    }),* $(,)?) => {
+        impl<S: Types> Types for MarkedTypes<S> {
+            $(type $name = Marked<S::$name, client::$name>;)*
+        }
+
+        $(impl<S: $name> $name for MarkedTypes<S> {
+            $(fn $method(&mut self, $($arg: $arg_ty),*) $(-> $ret_ty)? {
+                <_>::mark($name::$method(&mut self.0, $($arg.unmark()),*))
+            })*
+        })*
+    }
+}
+with_api!(Self, self_, define_mark_types_impls);
+
+struct Dispatcher<S: Types> {
+    handle_store: HandleStore<S>,
+    server: S,
+}
+
+macro_rules! define_dispatcher_impl {
+    ($($name:ident {
+        $(fn $method:ident($($arg:ident: $arg_ty:ty),* $(,)?) $(-> $ret_ty:ty)?;)*
+    }),* $(,)?) => {
+        // FIXME(eddyb) `pub` only for `ExecutionStrategy` below.
+        pub trait DispatcherTrait {
+            // HACK(eddyb) these are here to allow `Self::$name` to work below.
+            $(type $name;)*
+            fn dispatch(&mut self, buf: Buffer) -> Buffer;
+        }
+
+        impl<S: Server> DispatcherTrait for Dispatcher<MarkedTypes<S>> {
+            $(type $name = <MarkedTypes<S> as Types>::$name;)*
+            fn dispatch(&mut self, mut buf: Buffer) -> Buffer {
+                let Dispatcher { handle_store, server } = self;
+
+                let mut reader = &buf[..];
+                match api_tags::Method::decode(&mut reader, &mut ()) {
+                    $(api_tags::Method::$name(m) => match m {
+                        $(api_tags::$name::$method => {
+                            let mut call_method = || {
+                                reverse_decode!(reader, handle_store; $($arg: $arg_ty),*);
+                                $name::$method(server, $($arg),*)
+                            };
+                            // HACK(eddyb) don't use `panic::catch_unwind` in a panic.
+                            // If client and server happen to use the same `libstd`,
+                            // `catch_unwind` asserts that the panic counter was 0,
+                            // even when the closure passed to it didn't panic.
+                            let r = if thread::panicking() {
+                                Ok(call_method())
+                            } else {
+                                panic::catch_unwind(panic::AssertUnwindSafe(call_method))
+                                    .map_err(PanicMessage::from)
+                            };
+
+                            buf.clear();
+                            r.encode(&mut buf, handle_store);
+                        })*
+                    }),*
+                }
+                buf
+            }
+        }
+    }
+}
+with_api!(Self, self_, define_dispatcher_impl);
+
+pub trait ExecutionStrategy {
+    fn run_bridge_and_client(
+        &self,
+        dispatcher: &mut impl DispatcherTrait,
+        input: Buffer,
+        run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
+        force_show_panics: bool,
+    ) -> Buffer;
+}
+
+pub struct SameThread;
+
+impl ExecutionStrategy for SameThread {
+    fn run_bridge_and_client(
+        &self,
+        dispatcher: &mut impl DispatcherTrait,
+        input: Buffer,
+        run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
+        force_show_panics: bool,
+    ) -> Buffer {
+        let mut dispatch = |buf| dispatcher.dispatch(buf);
+
+        run_client(BridgeConfig {
+            input,
+            dispatch: (&mut dispatch).into(),
+            force_show_panics,
+            _marker: marker::PhantomData,
+        })
+    }
+}
+
+// NOTE(eddyb) Two implementations are provided, the second one is a bit
+// faster but neither is anywhere near as fast as same-thread execution.
+
+pub struct CrossThread1;
+
+impl ExecutionStrategy for CrossThread1 {
+    fn run_bridge_and_client(
+        &self,
+        dispatcher: &mut impl DispatcherTrait,
+        input: Buffer,
+        run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
+        force_show_panics: bool,
+    ) -> Buffer {
+        use std::sync::mpsc::channel;
+
+        let (req_tx, req_rx) = channel();
+        let (res_tx, res_rx) = channel();
+
+        let join_handle = thread::spawn(move || {
+            let mut dispatch = |buf| {
+                req_tx.send(buf).unwrap();
+                res_rx.recv().unwrap()
+            };
+
+            run_client(BridgeConfig {
+                input,
+                dispatch: (&mut dispatch).into(),
+                force_show_panics,
+                _marker: marker::PhantomData,
+            })
+        });
+
+        for b in req_rx {
+            res_tx.send(dispatcher.dispatch(b)).unwrap();
+        }
+
+        join_handle.join().unwrap()
+    }
+}
+
+pub struct CrossThread2;
+
+impl ExecutionStrategy for CrossThread2 {
+    fn run_bridge_and_client(
+        &self,
+        dispatcher: &mut impl DispatcherTrait,
+        input: Buffer,
+        run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
+        force_show_panics: bool,
+    ) -> Buffer {
+        use std::sync::{Arc, Mutex};
+
+        enum State<T> {
+            Req(T),
+            Res(T),
+        }
+
+        let mut state = Arc::new(Mutex::new(State::Res(Buffer::new())));
+
+        let server_thread = thread::current();
+        let state2 = state.clone();
+        let join_handle = thread::spawn(move || {
+            let mut dispatch = |b| {
+                *state2.lock().unwrap() = State::Req(b);
+                server_thread.unpark();
+                loop {
+                    thread::park();
+                    if let State::Res(b) = &mut *state2.lock().unwrap() {
+                        break b.take();
+                    }
+                }
+            };
+
+            let r = run_client(BridgeConfig {
+                input,
+                dispatch: (&mut dispatch).into(),
+                force_show_panics,
+                _marker: marker::PhantomData,
+            });
+
+            // Wake up the server so it can exit the dispatch loop.
+            drop(state2);
+            server_thread.unpark();
+
+            r
+        });
+
+        // Check whether `state2` was dropped, to know when to stop.
+        while Arc::get_mut(&mut state).is_none() {
+            thread::park();
+            let mut b = match &mut *state.lock().unwrap() {
+                State::Req(b) => b.take(),
+                _ => continue,
+            };
+            b = dispatcher.dispatch(b.take());
+            *state.lock().unwrap() = State::Res(b);
+            join_handle.thread().unpark();
+        }
+
+        join_handle.join().unwrap()
+    }
+}
+
+fn run_server<
+    S: Server,
+    I: Encode<HandleStore<MarkedTypes<S>>>,
+    O: for<'a, 's> DecodeMut<'a, 's, HandleStore<MarkedTypes<S>>>,
+>(
+    strategy: &impl ExecutionStrategy,
+    handle_counters: &'static client::HandleCounters,
+    server: S,
+    input: I,
+    run_client: extern "C" fn(BridgeConfig<'_>) -> Buffer,
+    force_show_panics: bool,
+) -> Result<O, PanicMessage> {
+    let mut dispatcher =
+        Dispatcher { handle_store: HandleStore::new(handle_counters), server: MarkedTypes(server) };
+
+    let globals = dispatcher.server.globals();
+
+    let mut buf = Buffer::new();
+    (globals, input).encode(&mut buf, &mut dispatcher.handle_store);
+
+    buf = strategy.run_bridge_and_client(&mut dispatcher, buf, run_client, force_show_panics);
+
+    Result::decode(&mut &buf[..], &mut dispatcher.handle_store)
+}
+
+impl client::Client<super::super::TokenStream, super::super::TokenStream> {
+    pub fn run<S>(
+        &self,
+        strategy: &impl ExecutionStrategy,
+        server: S,
+        input: S::TokenStream,
+        force_show_panics: bool,
+    ) -> Result<S::TokenStream, PanicMessage>
+    where
+        S: Server,
+        S::TokenStream: Default,
+    {
+        let client::Client { get_handle_counters, run, _marker } = *self;
+        run_server(
+            strategy,
+            get_handle_counters(),
+            server,
+            <MarkedTypes<S> as Types>::TokenStream::mark(input),
+            run,
+            force_show_panics,
+        )
+        .map(|s| <Option<<MarkedTypes<S> as Types>::TokenStream>>::unmark(s).unwrap_or_default())
+    }
+}
+
+impl
+    client::Client<
+        (super::super::TokenStream, super::super::TokenStream),
+        super::super::TokenStream,
+    >
+{
+    pub fn run<S>(
+        &self,
+        strategy: &impl ExecutionStrategy,
+        server: S,
+        input: S::TokenStream,
+        input2: S::TokenStream,
+        force_show_panics: bool,
+    ) -> Result<S::TokenStream, PanicMessage>
+    where
+        S: Server,
+        S::TokenStream: Default,
+    {
+        let client::Client { get_handle_counters, run, _marker } = *self;
+        run_server(
+            strategy,
+            get_handle_counters(),
+            server,
+            (
+                <MarkedTypes<S> as Types>::TokenStream::mark(input),
+                <MarkedTypes<S> as Types>::TokenStream::mark(input2),
+            ),
+            run,
+            force_show_panics,
+        )
+        .map(|s| <Option<<MarkedTypes<S> as Types>::TokenStream>>::unmark(s).unwrap_or_default())
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/diagnostic.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/diagnostic.rs
new file mode 100644
index 0000000000..3fade2dc4f
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/diagnostic.rs
@@ -0,0 +1,166 @@
+//! lib-proc-macro diagnostic
+//!
+//! Copy from <https://github.com/rust-lang/rust/blob/e45d9973b2665897a768312e971b82cc62633103/src/libproc_macro/diagnostic.rs>
+//! augmented with removing unstable features
+
+use super::Span;
+
+/// An enum representing a diagnostic level.
+#[derive(Copy, Clone, Debug)]
+#[non_exhaustive]
+pub enum Level {
+    /// An error.
+    Error,
+    /// A warning.
+    Warning,
+    /// A note.
+    Note,
+    /// A help message.
+    Help,
+}
+
+/// Trait implemented by types that can be converted into a set of `Span`s.
+pub trait MultiSpan {
+    /// Converts `self` into a `Vec<Span>`.
+    fn into_spans(self) -> Vec<Span>;
+}
+
+impl MultiSpan for Span {
+    fn into_spans(self) -> Vec<Span> {
+        vec![self]
+    }
+}
+
+impl MultiSpan for Vec<Span> {
+    fn into_spans(self) -> Vec<Span> {
+        self
+    }
+}
+
+impl<'a> MultiSpan for &'a [Span] {
+    fn into_spans(self) -> Vec<Span> {
+        self.to_vec()
+    }
+}
+
+/// A structure representing a diagnostic message and associated children
+/// messages.
+#[derive(Clone, Debug)]
+pub struct Diagnostic {
+    level: Level,
+    message: String,
+    spans: Vec<Span>,
+    children: Vec<Diagnostic>,
+}
+
+macro_rules! diagnostic_child_methods {
+    ($spanned:ident, $regular:ident, $level:expr) => {
+        #[doc = concat!("Adds a new child diagnostics message to `self` with the [`",
+                        stringify!($level), "`] level, and the given `spans` and `message`.")]
+        pub fn $spanned<S, T>(mut self, spans: S, message: T) -> Diagnostic
+        where
+            S: MultiSpan,
+            T: Into<String>,
+        {
+            self.children.push(Diagnostic::spanned(spans, $level, message));
+            self
+        }
+
+        #[doc = concat!("Adds a new child diagnostic message to `self` with the [`",
+                        stringify!($level), "`] level, and the given `message`.")]
+        pub fn $regular<T: Into<String>>(mut self, message: T) -> Diagnostic {
+            self.children.push(Diagnostic::new($level, message));
+            self
+        }
+    };
+}
+
+/// Iterator over the children diagnostics of a `Diagnostic`.
+#[derive(Debug, Clone)]
+pub struct Children<'a>(std::slice::Iter<'a, Diagnostic>);
+
+impl<'a> Iterator for Children<'a> {
+    type Item = &'a Diagnostic;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+impl Diagnostic {
+    /// Creates a new diagnostic with the given `level` and `message`.
+    pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
+        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
+    }
+
+    /// Creates a new diagnostic with the given `level` and `message` pointing to
+    /// the given set of `spans`.
+    pub fn spanned<S, T>(spans: S, level: Level, message: T) -> Diagnostic
+    where
+        S: MultiSpan,
+        T: Into<String>,
+    {
+        Diagnostic { level, message: message.into(), spans: spans.into_spans(), children: vec![] }
+    }
+
+    diagnostic_child_methods!(span_error, error, Level::Error);
+    diagnostic_child_methods!(span_warning, warning, Level::Warning);
+    diagnostic_child_methods!(span_note, note, Level::Note);
+    diagnostic_child_methods!(span_help, help, Level::Help);
+
+    /// Returns the diagnostic `level` for `self`.
+    pub fn level(&self) -> Level {
+        self.level
+    }
+
+    /// Sets the level in `self` to `level`.
+    pub fn set_level(&mut self, level: Level) {
+        self.level = level;
+    }
+
+    /// Returns the message in `self`.
+    pub fn message(&self) -> &str {
+        &self.message
+    }
+
+    /// Sets the message in `self` to `message`.
+    pub fn set_message<T: Into<String>>(&mut self, message: T) {
+        self.message = message.into();
+    }
+
+    /// Returns the `Span`s in `self`.
+    pub fn spans(&self) -> &[Span] {
+        &self.spans
+    }
+
+    /// Sets the `Span`s in `self` to `spans`.
+    pub fn set_spans<S: MultiSpan>(&mut self, spans: S) {
+        self.spans = spans.into_spans();
+    }
+
+    /// Returns an iterator over the children diagnostics of `self`.
+    pub fn children(&self) -> Children<'_> {
+        Children(self.children.iter())
+    }
+
+    /// Emit the diagnostic.
+    pub fn emit(self) {
+        fn to_internal(spans: Vec<Span>) -> super::bridge::client::MultiSpan {
+            let mut multi_span = super::bridge::client::MultiSpan::new();
+            for span in spans {
+                multi_span.push(span.0);
+            }
+            multi_span
+        }
+
+        let mut diag = super::bridge::client::Diagnostic::new(
+            self.level,
+            &self.message[..],
+            to_internal(self.spans),
+        );
+        for c in self.children {
+            diag.sub(c.level, &c.message[..], to_internal(c.spans));
+        }
+        diag.emit();
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/mod.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/mod.rs
new file mode 100644
index 0000000000..86a59b6455
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/mod.rs
@@ -0,0 +1,1125 @@
+//! A support library for macro authors when defining new macros.
+//!
+//! This library, provided by the standard distribution, provides the types
+//! consumed in the interfaces of procedurally defined macro definitions such as
+//! function-like macros `#[proc_macro]`, macro attributes `#[proc_macro_attribute]` and
+//! custom derive attributes`#[proc_macro_derive]`.
+//!
+//! See [the book] for more.
+//!
+//! [the book]: ../book/ch19-06-macros.html#procedural-macros-for-generating-code-from-attributes
+
+#[doc(hidden)]
+pub mod bridge;
+
+mod diagnostic;
+
+pub use diagnostic::{Diagnostic, Level, MultiSpan};
+
+use std::cmp::Ordering;
+use std::ops::RangeBounds;
+use std::path::PathBuf;
+use std::str::FromStr;
+use std::{error, fmt, iter, mem};
+
+/// Determines whether proc_macro has been made accessible to the currently
+/// running program.
+///
+/// The proc_macro crate is only intended for use inside the implementation of
+/// procedural macros. All the functions in this crate panic if invoked from
+/// outside of a procedural macro, such as from a build script or unit test or
+/// ordinary Rust binary.
+///
+/// With consideration for Rust libraries that are designed to support both
+/// macro and non-macro use cases, `proc_macro::is_available()` provides a
+/// non-panicking way to detect whether the infrastructure required to use the
+/// API of proc_macro is presently available. Returns true if invoked from
+/// inside of a procedural macro, false if invoked from any other binary.
+pub fn is_available() -> bool {
+    bridge::client::is_available()
+}
+
+/// The main type provided by this crate, representing an abstract stream of
+/// tokens, or, more specifically, a sequence of token trees.
+/// The type provide interfaces for iterating over those token trees and, conversely,
+/// collecting a number of token trees into one stream.
+///
+/// This is both the input and output of `#[proc_macro]`, `#[proc_macro_attribute]`
+/// and `#[proc_macro_derive]` definitions.
+#[derive(Clone)]
+pub struct TokenStream(Option<bridge::client::TokenStream>);
+
+/// Error returned from `TokenStream::from_str`.
+#[non_exhaustive]
+#[derive(Debug)]
+pub struct LexError;
+
+impl fmt::Display for LexError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("cannot parse string into token stream")
+    }
+}
+
+impl error::Error for LexError {}
+
+/// Error returned from `TokenStream::expand_expr`.
+#[non_exhaustive]
+#[derive(Debug)]
+pub struct ExpandError;
+
+impl fmt::Display for ExpandError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("macro expansion failed")
+    }
+}
+
+impl error::Error for ExpandError {}
+
+impl TokenStream {
+    /// Returns an empty `TokenStream` containing no token trees.
+    pub fn new() -> TokenStream {
+        TokenStream(None)
+    }
+
+    /// Checks if this `TokenStream` is empty.
+    pub fn is_empty(&self) -> bool {
+        self.0.as_ref().map(|h| h.is_empty()).unwrap_or(true)
+    }
+
+    /// Parses this `TokenStream` as an expression and attempts to expand any
+    /// macros within it. Returns the expanded `TokenStream`.
+    ///
+    /// Currently only expressions expanding to literals will succeed, although
+    /// this may be relaxed in the future.
+    ///
+    /// NOTE: In error conditions, `expand_expr` may leave macros unexpanded,
+    /// report an error, failing compilation, and/or return an `Err(..)`. The
+    /// specific behavior for any error condition, and what conditions are
+    /// considered errors, is unspecified and may change in the future.
+    pub fn expand_expr(&self) -> Result<TokenStream, ExpandError> {
+        let stream = self.0.as_ref().ok_or(ExpandError)?;
+        match bridge::client::TokenStream::expand_expr(stream) {
+            Ok(stream) => Ok(TokenStream(Some(stream))),
+            Err(_) => Err(ExpandError),
+        }
+    }
+}
+
+/// Attempts to break the string into tokens and parse those tokens into a token stream.
+/// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
+/// or characters not existing in the language.
+/// All tokens in the parsed stream get `Span::call_site()` spans.
+///
+/// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
+/// change these errors into `LexError`s later.
+impl FromStr for TokenStream {
+    type Err = LexError;
+
+    fn from_str(src: &str) -> Result<TokenStream, LexError> {
+        Ok(TokenStream(Some(bridge::client::TokenStream::from_str(src))))
+    }
+}
+
+/// Prints the token stream as a string that is supposed to be losslessly convertible back
+/// into the same token stream (modulo spans), except for possibly `TokenTree::Group`s
+/// with `Delimiter::None` delimiters and negative numeric literals.
+impl fmt::Display for TokenStream {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+/// Prints token in a form convenient for debugging.
+impl fmt::Debug for TokenStream {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("TokenStream ")?;
+        f.debug_list().entries(self.clone()).finish()
+    }
+}
+
+impl Default for TokenStream {
+    fn default() -> Self {
+        TokenStream::new()
+    }
+}
+
+pub use quote::{quote, quote_span};
+
+fn tree_to_bridge_tree(
+    tree: TokenTree,
+) -> bridge::TokenTree<
+    bridge::client::TokenStream,
+    bridge::client::Span,
+    bridge::client::Ident,
+    bridge::client::Literal,
+> {
+    match tree {
+        TokenTree::Group(tt) => bridge::TokenTree::Group(tt.0),
+        TokenTree::Punct(tt) => bridge::TokenTree::Punct(tt.0),
+        TokenTree::Ident(tt) => bridge::TokenTree::Ident(tt.0),
+        TokenTree::Literal(tt) => bridge::TokenTree::Literal(tt.0),
+    }
+}
+
+/// Creates a token stream containing a single token tree.
+impl From<TokenTree> for TokenStream {
+    fn from(tree: TokenTree) -> TokenStream {
+        TokenStream(Some(bridge::client::TokenStream::from_token_tree(tree_to_bridge_tree(tree))))
+    }
+}
+
+/// Non-generic helper for implementing `FromIterator<TokenStream>` and
+/// `Extend<TokenStream>` with less monomorphization in calling crates.
+struct ConcatStreamsHelper {
+    streams: Vec<bridge::client::TokenStream>,
+}
+
+impl ConcatStreamsHelper {
+    fn new(capacity: usize) -> Self {
+        ConcatStreamsHelper { streams: Vec::with_capacity(capacity) }
+    }
+
+    fn push(&mut self, stream: TokenStream) {
+        if let Some(stream) = stream.0 {
+            self.streams.push(stream);
+        }
+    }
+
+    fn build(mut self) -> TokenStream {
+        if self.streams.len() <= 1 {
+            TokenStream(self.streams.pop())
+        } else {
+            TokenStream(Some(bridge::client::TokenStream::concat_streams(None, self.streams)))
+        }
+    }
+
+    fn append_to(mut self, stream: &mut TokenStream) {
+        if self.streams.is_empty() {
+            return;
+        }
+        let base = stream.0.take();
+        if base.is_none() && self.streams.len() == 1 {
+            stream.0 = self.streams.pop();
+        } else {
+            stream.0 = Some(bridge::client::TokenStream::concat_streams(base, self.streams));
+        }
+    }
+}
+
+/// Collects a number of token trees into a single stream.
+impl FromIterator<TokenTree> for TokenStream {
+    fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
+        trees.into_iter().map(TokenStream::from).collect()
+    }
+}
+
+/// A "flattening" operation on token streams, collects token trees
+/// from multiple token streams into a single stream.
+impl FromIterator<TokenStream> for TokenStream {
+    fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
+        let iter = streams.into_iter();
+        let mut builder = ConcatStreamsHelper::new(iter.size_hint().0);
+        iter.for_each(|stream| builder.push(stream));
+        builder.build()
+    }
+}
+
+impl Extend<TokenTree> for TokenStream {
+    fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) {
+        self.extend(trees.into_iter().map(TokenStream::from));
+    }
+}
+
+impl Extend<TokenStream> for TokenStream {
+    fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
+        // FIXME(eddyb) Use an optimized implementation if/when possible.
+        *self = iter::once(mem::replace(self, Self::new())).chain(streams).collect();
+    }
+}
+
+/// Public implementation details for the `TokenStream` type, such as iterators.
+pub mod token_stream {
+    use super::{bridge, Group, Ident, Literal, Punct, TokenStream, TokenTree};
+
+    /// An iterator over `TokenStream`'s `TokenTree`s.
+    /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
+    /// and returns whole groups as token trees.
+    #[derive(Clone)]
+    pub struct IntoIter(
+        std::vec::IntoIter<
+            bridge::TokenTree<
+                bridge::client::TokenStream,
+                bridge::client::Span,
+                bridge::client::Ident,
+                bridge::client::Literal,
+            >,
+        >,
+    );
+
+    impl Iterator for IntoIter {
+        type Item = TokenTree;
+
+        fn next(&mut self) -> Option<TokenTree> {
+            self.0.next().map(|tree| match tree {
+                bridge::TokenTree::Group(tt) => TokenTree::Group(Group(tt)),
+                bridge::TokenTree::Punct(tt) => TokenTree::Punct(Punct(tt)),
+                bridge::TokenTree::Ident(tt) => TokenTree::Ident(Ident(tt)),
+                bridge::TokenTree::Literal(tt) => TokenTree::Literal(Literal(tt)),
+            })
+        }
+    }
+
+    impl IntoIterator for TokenStream {
+        type Item = TokenTree;
+        type IntoIter = IntoIter;
+
+        fn into_iter(self) -> IntoIter {
+            IntoIter(self.0.map(|v| v.into_trees()).unwrap_or_default().into_iter())
+        }
+    }
+}
+
+#[doc(hidden)]
+mod quote;
+
+/// A region of source code, along with macro expansion information.
+#[derive(Copy, Clone)]
+pub struct Span(bridge::client::Span);
+
+macro_rules! diagnostic_method {
+    ($name:ident, $level:expr) => {
+        /// Creates a new `Diagnostic` with the given `message` at the span
+        /// `self`.
+        pub fn $name<T: Into<String>>(self, message: T) -> Diagnostic {
+            Diagnostic::spanned(self, $level, message)
+        }
+    };
+}
+
+impl Span {
+    /// A span that resolves at the macro definition site.
+    pub fn def_site() -> Span {
+        Span(bridge::client::Span::def_site())
+    }
+
+    /// The span of the invocation of the current procedural macro.
+    /// Identifiers created with this span will be resolved as if they were written
+    /// directly at the macro call location (call-site hygiene) and other code
+    /// at the macro call site will be able to refer to them as well.
+    pub fn call_site() -> Span {
+        Span(bridge::client::Span::call_site())
+    }
+
+    /// A span that represents `macro_rules` hygiene, and sometimes resolves at the macro
+    /// definition site (local variables, labels, `$crate`) and sometimes at the macro
+    /// call site (everything else).
+    /// The span location is taken from the call-site.
+    pub fn mixed_site() -> Span {
+        Span(bridge::client::Span::mixed_site())
+    }
+
+    /// The original source file into which this span points.
+    pub fn source_file(&self) -> SourceFile {
+        SourceFile(self.0.source_file())
+    }
+
+    /// The `Span` for the tokens in the previous macro expansion from which
+    /// `self` was generated from, if any.
+    pub fn parent(&self) -> Option<Span> {
+        self.0.parent().map(Span)
+    }
+
+    /// The span for the origin source code that `self` was generated from. If
+    /// this `Span` wasn't generated from other macro expansions then the return
+    /// value is the same as `*self`.
+    pub fn source(&self) -> Span {
+        Span(self.0.source())
+    }
+
+    /// Gets the starting line/column in the source file for this span.
+    pub fn start(&self) -> LineColumn {
+        self.0.start().add_1_to_column()
+    }
+
+    /// Gets the ending line/column in the source file for this span.
+    pub fn end(&self) -> LineColumn {
+        self.0.end().add_1_to_column()
+    }
+
+    /// Creates an empty span pointing to directly before this span.
+    pub fn before(&self) -> Span {
+        Span(self.0.before())
+    }
+
+    /// Creates an empty span pointing to directly after this span.
+    pub fn after(&self) -> Span {
+        Span(self.0.after())
+    }
+
+    /// Creates a new span encompassing `self` and `other`.
+    ///
+    /// Returns `None` if `self` and `other` are from different files.
+    pub fn join(&self, other: Span) -> Option<Span> {
+        self.0.join(other.0).map(Span)
+    }
+
+    /// Creates a new span with the same line/column information as `self` but
+    /// that resolves symbols as though it were at `other`.
+    pub fn resolved_at(&self, other: Span) -> Span {
+        Span(self.0.resolved_at(other.0))
+    }
+
+    /// Creates a new span with the same name resolution behavior as `self` but
+    /// with the line/column information of `other`.
+    pub fn located_at(&self, other: Span) -> Span {
+        other.resolved_at(*self)
+    }
+
+    /// Compares to spans to see if they're equal.
+    pub fn eq(&self, other: &Span) -> bool {
+        self.0 == other.0
+    }
+
+    /// Returns the source text behind a span. This preserves the original source
+    /// code, including spaces and comments. It only returns a result if the span
+    /// corresponds to real source code.
+    ///
+    /// Note: The observable result of a macro should only rely on the tokens and
+    /// not on this source text. The result of this function is a best effort to
+    /// be used for diagnostics only.
+    pub fn source_text(&self) -> Option<String> {
+        self.0.source_text()
+    }
+
+    // Used by the implementation of `Span::quote`
+    #[doc(hidden)]
+    pub fn save_span(&self) -> usize {
+        self.0.save_span()
+    }
+
+    // Used by the implementation of `Span::quote`
+    #[doc(hidden)]
+    pub fn recover_proc_macro_span(id: usize) -> Span {
+        Span(bridge::client::Span::recover_proc_macro_span(id))
+    }
+
+    diagnostic_method!(error, Level::Error);
+    diagnostic_method!(warning, Level::Warning);
+    diagnostic_method!(note, Level::Note);
+    diagnostic_method!(help, Level::Help);
+}
+
+/// Prints a span in a form convenient for debugging.
+impl fmt::Debug for Span {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+/// A line-column pair representing the start or end of a `Span`.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub struct LineColumn {
+    /// The 1-indexed line in the source file on which the span starts or ends (inclusive).
+    pub line: usize,
+    /// The 1-indexed column (number of bytes in UTF-8 encoding) in the source
+    /// file on which the span starts or ends (inclusive).
+    pub column: usize,
+}
+
+impl LineColumn {
+    fn add_1_to_column(self) -> Self {
+        LineColumn { line: self.line, column: self.column + 1 }
+    }
+}
+
+impl Ord for LineColumn {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.line.cmp(&other.line).then(self.column.cmp(&other.column))
+    }
+}
+
+impl PartialOrd for LineColumn {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+/// The source file of a given `Span`.
+#[derive(Clone)]
+pub struct SourceFile(bridge::client::SourceFile);
+
+impl SourceFile {
+    /// Gets the path to this source file.
+    ///
+    /// ### Note
+    /// If the code span associated with this `SourceFile` was generated by an external macro, this
+    /// macro, this might not be an actual path on the filesystem. Use [`is_real`] to check.
+    ///
+    /// Also note that even if `is_real` returns `true`, if `--remap-path-prefix` was passed on
+    /// the command line, the path as given might not actually be valid.
+    ///
+    /// [`is_real`]: Self::is_real
+    pub fn path(&self) -> PathBuf {
+        PathBuf::from(self.0.path())
+    }
+
+    /// Returns `true` if this source file is a real source file, and not generated by an external
+    /// macro's expansion.
+    pub fn is_real(&self) -> bool {
+        // This is a hack until intercrate spans are implemented and we can have real source files
+        // for spans generated in external macros.
+        // https://github.com/rust-lang/rust/pull/43604#issuecomment-333334368
+        self.0.is_real()
+    }
+}
+
+impl fmt::Debug for SourceFile {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("SourceFile")
+            .field("path", &self.path())
+            .field("is_real", &self.is_real())
+            .finish()
+    }
+}
+
+impl PartialEq for SourceFile {
+    fn eq(&self, other: &Self) -> bool {
+        self.0.eq(&other.0)
+    }
+}
+
+impl Eq for SourceFile {}
+
+/// A single token or a delimited sequence of token trees (e.g., `[1, (), ..]`).
+#[derive(Clone)]
+pub enum TokenTree {
+    /// A token stream surrounded by bracket delimiters.
+    Group(Group),
+    /// An identifier.
+    Ident(Ident),
+    /// A single punctuation character (`+`, `,`, `$`, etc.).
+    Punct(Punct),
+    /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
+    Literal(Literal),
+}
+
+impl TokenTree {
+    /// Returns the span of this tree, delegating to the `span` method of
+    /// the contained token or a delimited stream.
+    pub fn span(&self) -> Span {
+        match *self {
+            TokenTree::Group(ref t) => t.span(),
+            TokenTree::Ident(ref t) => t.span(),
+            TokenTree::Punct(ref t) => t.span(),
+            TokenTree::Literal(ref t) => t.span(),
+        }
+    }
+
+    /// Configures the span for *only this token*.
+    ///
+    /// Note that if this token is a `Group` then this method will not configure
+    /// the span of each of the internal tokens, this will simply delegate to
+    /// the `set_span` method of each variant.
+    pub fn set_span(&mut self, span: Span) {
+        match *self {
+            TokenTree::Group(ref mut t) => t.set_span(span),
+            TokenTree::Ident(ref mut t) => t.set_span(span),
+            TokenTree::Punct(ref mut t) => t.set_span(span),
+            TokenTree::Literal(ref mut t) => t.set_span(span),
+        }
+    }
+}
+
+/// Prints token tree in a form convenient for debugging.
+impl fmt::Debug for TokenTree {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // Each of these has the name in the struct type in the derived debug,
+        // so don't bother with an extra layer of indirection
+        match *self {
+            TokenTree::Group(ref tt) => tt.fmt(f),
+            TokenTree::Ident(ref tt) => tt.fmt(f),
+            TokenTree::Punct(ref tt) => tt.fmt(f),
+            TokenTree::Literal(ref tt) => tt.fmt(f),
+        }
+    }
+}
+
+impl From<Group> for TokenTree {
+    fn from(g: Group) -> TokenTree {
+        TokenTree::Group(g)
+    }
+}
+
+impl From<Ident> for TokenTree {
+    fn from(g: Ident) -> TokenTree {
+        TokenTree::Ident(g)
+    }
+}
+
+impl From<Punct> for TokenTree {
+    fn from(g: Punct) -> TokenTree {
+        TokenTree::Punct(g)
+    }
+}
+
+impl From<Literal> for TokenTree {
+    fn from(g: Literal) -> TokenTree {
+        TokenTree::Literal(g)
+    }
+}
+
+/// Prints the token tree as a string that is supposed to be losslessly convertible back
+/// into the same token tree (modulo spans), except for possibly `TokenTree::Group`s
+/// with `Delimiter::None` delimiters and negative numeric literals.
+impl fmt::Display for TokenTree {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+/// A delimited token stream.
+///
+/// A `Group` internally contains a `TokenStream` which is surrounded by `Delimiter`s.
+#[derive(Clone)]
+pub struct Group(bridge::Group<bridge::client::TokenStream, bridge::client::Span>);
+
+/// Describes how a sequence of token trees is delimited.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum Delimiter {
+    /// `( ... )`
+    Parenthesis,
+    /// `{ ... }`
+    Brace,
+    /// `[ ... ]`
+    Bracket,
+    /// `Ø ... Ø`
+    /// An invisible delimiter, that may, for example, appear around tokens coming from a
+    /// "macro variable" `$var`. It is important to preserve operator priorities in cases like
+    /// `$var * 3` where `$var` is `1 + 2`.
+    /// Invisible delimiters might not survive roundtrip of a token stream through a string.
+    None,
+}
+
+impl Group {
+    /// Creates a new `Group` with the given delimiter and token stream.
+    ///
+    /// This constructor will set the span for this group to
+    /// `Span::call_site()`. To change the span you can use the `set_span`
+    /// method below.
+    pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
+        Group(bridge::Group {
+            delimiter,
+            stream: stream.0,
+            span: bridge::DelimSpan::from_single(Span::call_site().0),
+        })
+    }
+
+    /// Returns the delimiter of this `Group`
+    pub fn delimiter(&self) -> Delimiter {
+        self.0.delimiter
+    }
+
+    /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
+    ///
+    /// Note that the returned token stream does not include the delimiter
+    /// returned above.
+    pub fn stream(&self) -> TokenStream {
+        TokenStream(self.0.stream.clone())
+    }
+
+    /// Returns the span for the delimiters of this token stream, spanning the
+    /// entire `Group`.
+    ///
+    /// ```text
+    /// pub fn span(&self) -> Span {
+    ///            ^^^^^^^
+    /// ```
+    pub fn span(&self) -> Span {
+        Span(self.0.span.entire)
+    }
+
+    /// Returns the span pointing to the opening delimiter of this group.
+    ///
+    /// ```text
+    /// pub fn span_open(&self) -> Span {
+    ///                 ^
+    /// ```
+    pub fn span_open(&self) -> Span {
+        Span(self.0.span.open)
+    }
+
+    /// Returns the span pointing to the closing delimiter of this group.
+    ///
+    /// ```text
+    /// pub fn span_close(&self) -> Span {
+    ///                        ^
+    /// ```
+    pub fn span_close(&self) -> Span {
+        Span(self.0.span.close)
+    }
+
+    /// Configures the span for this `Group`'s delimiters, but not its internal
+    /// tokens.
+    ///
+    /// This method will **not** set the span of all the internal tokens spanned
+    /// by this group, but rather it will only set the span of the delimiter
+    /// tokens at the level of the `Group`.
+    pub fn set_span(&mut self, span: Span) {
+        self.0.span = bridge::DelimSpan::from_single(span.0);
+    }
+}
+
+/// Prints the group as a string that should be losslessly convertible back
+/// into the same group (modulo spans), except for possibly `TokenTree::Group`s
+/// with `Delimiter::None` delimiters.
+impl fmt::Display for Group {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+impl fmt::Debug for Group {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Group")
+            .field("delimiter", &self.delimiter())
+            .field("stream", &self.stream())
+            .field("span", &self.span())
+            .finish()
+    }
+}
+
+/// A `Punct` is a single punctuation character such as `+`, `-` or `#`.
+///
+/// Multi-character operators like `+=` are represented as two instances of `Punct` with different
+/// forms of `Spacing` returned.
+#[derive(Clone)]
+pub struct Punct(bridge::Punct<bridge::client::Span>);
+
+/// Describes whether a `Punct` is followed immediately by another `Punct` ([`Spacing::Joint`]) or
+/// by a different token or whitespace ([`Spacing::Alone`]).
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub enum Spacing {
+    /// A `Punct` is not immediately followed by another `Punct`.
+    /// E.g. `+` is `Alone` in `+ =`, `+ident` and `+()`.
+    Alone,
+    /// A `Punct` is immediately followed by another `Punct`.
+    /// E.g. `+` is `Joint` in `+=` and `++`.
+    ///
+    /// Additionally, single quote `'` can join with identifiers to form lifetimes: `'ident`.
+    Joint,
+}
+
+impl Punct {
+    /// Creates a new `Punct` from the given character and spacing.
+    /// The `ch` argument must be a valid punctuation character permitted by the language,
+    /// otherwise the function will panic.
+    ///
+    /// The returned `Punct` will have the default span of `Span::call_site()`
+    /// which can be further configured with the `set_span` method below.
+    pub fn new(ch: char, spacing: Spacing) -> Punct {
+        const LEGAL_CHARS: &[char] = &[
+            '=', '<', '>', '!', '~', '+', '-', '*', '/', '%', '^', '&', '|', '@', '.', ',', ';',
+            ':', '#', '$', '?', '\'',
+        ];
+        if !LEGAL_CHARS.contains(&ch) {
+            panic!("unsupported character `{:?}`", ch);
+        }
+        Punct(bridge::Punct {
+            ch: ch as u8,
+            joint: spacing == Spacing::Joint,
+            span: Span::call_site().0,
+        })
+    }
+
+    /// Returns the value of this punctuation character as `char`.
+    pub fn as_char(&self) -> char {
+        self.0.ch as char
+    }
+
+    /// Returns the spacing of this punctuation character, indicating whether it's immediately
+    /// followed by another `Punct` in the token stream, so they can potentially be combined into
+    /// a multi-character operator (`Joint`), or it's followed by some other token or whitespace
+    /// (`Alone`) so the operator has certainly ended.
+    pub fn spacing(&self) -> Spacing {
+        if self.0.joint {
+            Spacing::Joint
+        } else {
+            Spacing::Alone
+        }
+    }
+
+    /// Returns the span for this punctuation character.
+    pub fn span(&self) -> Span {
+        Span(self.0.span)
+    }
+
+    /// Configure the span for this punctuation character.
+    pub fn set_span(&mut self, span: Span) {
+        self.0.span = span.0;
+    }
+}
+
+/// Prints the punctuation character as a string that should be losslessly convertible
+/// back into the same character.
+impl fmt::Display for Punct {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+impl fmt::Debug for Punct {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Punct")
+            .field("ch", &self.as_char())
+            .field("spacing", &self.spacing())
+            .field("span", &self.span())
+            .finish()
+    }
+}
+
+impl PartialEq<char> for Punct {
+    fn eq(&self, rhs: &char) -> bool {
+        self.as_char() == *rhs
+    }
+}
+
+impl PartialEq<Punct> for char {
+    fn eq(&self, rhs: &Punct) -> bool {
+        *self == rhs.as_char()
+    }
+}
+
+/// An identifier (`ident`).
+#[derive(Clone)]
+pub struct Ident(bridge::client::Ident);
+
+impl Ident {
+    /// Creates a new `Ident` with the given `string` as well as the specified
+    /// `span`.
+    /// The `string` argument must be a valid identifier permitted by the
+    /// language (including keywords, e.g. `self` or `fn`). Otherwise, the function will panic.
+    ///
+    /// Note that `span`, currently in rustc, configures the hygiene information
+    /// for this identifier.
+    ///
+    /// As of this time `Span::call_site()` explicitly opts-in to "call-site" hygiene
+    /// meaning that identifiers created with this span will be resolved as if they were written
+    /// directly at the location of the macro call, and other code at the macro call site will be
+    /// able to refer to them as well.
+    ///
+    /// Later spans like `Span::def_site()` will allow to opt-in to "definition-site" hygiene
+    /// meaning that identifiers created with this span will be resolved at the location of the
+    /// macro definition and other code at the macro call site will not be able to refer to them.
+    ///
+    /// Due to the current importance of hygiene this constructor, unlike other
+    /// tokens, requires a `Span` to be specified at construction.
+    pub fn new(string: &str, span: Span) -> Ident {
+        Ident(bridge::client::Ident::new(string, span.0, false))
+    }
+
+    /// Same as `Ident::new`, but creates a raw identifier (`r#ident`).
+    /// The `string` argument be a valid identifier permitted by the language
+    /// (including keywords, e.g. `fn`). Keywords which are usable in path segments
+    /// (e.g. `self`, `super`) are not supported, and will cause a panic.
+    pub fn new_raw(string: &str, span: Span) -> Ident {
+        Ident(bridge::client::Ident::new(string, span.0, true))
+    }
+
+    /// Returns the span of this `Ident`, encompassing the entire string returned
+    /// by [`to_string`](Self::to_string).
+    pub fn span(&self) -> Span {
+        Span(self.0.span())
+    }
+
+    /// Configures the span of this `Ident`, possibly changing its hygiene context.
+    pub fn set_span(&mut self, span: Span) {
+        self.0 = self.0.with_span(span.0);
+    }
+}
+
+/// Prints the identifier as a string that should be losslessly convertible
+/// back into the same identifier.
+impl fmt::Display for Ident {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+impl fmt::Debug for Ident {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Ident")
+            .field("ident", &self.to_string())
+            .field("span", &self.span())
+            .finish()
+    }
+}
+
+/// A literal string (`"hello"`), byte string (`b"hello"`),
+/// character (`'a'`), byte character (`b'a'`), an integer or floating point number
+/// with or without a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
+/// Boolean literals like `true` and `false` do not belong here, they are `Ident`s.
+#[derive(Clone)]
+pub struct Literal(bridge::client::Literal);
+
+macro_rules! suffixed_int_literals {
+    ($($name:ident => $kind:ident,)*) => ($(
+        /// Creates a new suffixed integer literal with the specified value.
+        ///
+        /// This function will create an integer like `1u32` where the integer
+        /// value specified is the first part of the token and the integral is
+        /// also suffixed at the end.
+        /// Literals created from negative numbers might not survive round-trips through
+        /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
+        ///
+        /// Literals created through this method have the `Span::call_site()`
+        /// span by default, which can be configured with the `set_span` method
+        /// below.
+        pub fn $name(n: $kind) -> Literal {
+            Literal(bridge::client::Literal::typed_integer(&n.to_string(), stringify!($kind)))
+        }
+    )*)
+}
+
+macro_rules! unsuffixed_int_literals {
+    ($($name:ident => $kind:ident,)*) => ($(
+        /// Creates a new unsuffixed integer literal with the specified value.
+        ///
+        /// This function will create an integer like `1` where the integer
+        /// value specified is the first part of the token. No suffix is
+        /// specified on this token, meaning that invocations like
+        /// `Literal::i8_unsuffixed(1)` are equivalent to
+        /// `Literal::u32_unsuffixed(1)`.
+        /// Literals created from negative numbers might not survive rountrips through
+        /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
+        ///
+        /// Literals created through this method have the `Span::call_site()`
+        /// span by default, which can be configured with the `set_span` method
+        /// below.
+        pub fn $name(n: $kind) -> Literal {
+            Literal(bridge::client::Literal::integer(&n.to_string()))
+        }
+    )*)
+}
+
+impl Literal {
+    suffixed_int_literals! {
+        u8_suffixed => u8,
+        u16_suffixed => u16,
+        u32_suffixed => u32,
+        u64_suffixed => u64,
+        u128_suffixed => u128,
+        usize_suffixed => usize,
+        i8_suffixed => i8,
+        i16_suffixed => i16,
+        i32_suffixed => i32,
+        i64_suffixed => i64,
+        i128_suffixed => i128,
+        isize_suffixed => isize,
+    }
+
+    unsuffixed_int_literals! {
+        u8_unsuffixed => u8,
+        u16_unsuffixed => u16,
+        u32_unsuffixed => u32,
+        u64_unsuffixed => u64,
+        u128_unsuffixed => u128,
+        usize_unsuffixed => usize,
+        i8_unsuffixed => i8,
+        i16_unsuffixed => i16,
+        i32_unsuffixed => i32,
+        i64_unsuffixed => i64,
+        i128_unsuffixed => i128,
+        isize_unsuffixed => isize,
+    }
+
+    /// Creates a new unsuffixed floating-point literal.
+    ///
+    /// This constructor is similar to those like `Literal::i8_unsuffixed` where
+    /// the float's value is emitted directly into the token but no suffix is
+    /// used, so it may be inferred to be a `f64` later in the compiler.
+    /// Literals created from negative numbers might not survive rountrips through
+    /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
+    ///
+    /// # Panics
+    ///
+    /// This function requires that the specified float is finite, for
+    /// example if it is infinity or NaN this function will panic.
+    pub fn f32_unsuffixed(n: f32) -> Literal {
+        if !n.is_finite() {
+            panic!("Invalid float literal {n}");
+        }
+        let mut repr = n.to_string();
+        if !repr.contains('.') {
+            repr.push_str(".0");
+        }
+        Literal(bridge::client::Literal::float(&repr))
+    }
+
+    /// Creates a new suffixed floating-point literal.
+    ///
+    /// This constructor will create a literal like `1.0f32` where the value
+    /// specified is the preceding part of the token and `f32` is the suffix of
+    /// the token. This token will always be inferred to be an `f32` in the
+    /// compiler.
+    /// Literals created from negative numbers might not survive rountrips through
+    /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
+    ///
+    /// # Panics
+    ///
+    /// This function requires that the specified float is finite, for
+    /// example if it is infinity or NaN this function will panic.
+    pub fn f32_suffixed(n: f32) -> Literal {
+        if !n.is_finite() {
+            panic!("Invalid float literal {n}");
+        }
+        Literal(bridge::client::Literal::f32(&n.to_string()))
+    }
+
+    /// Creates a new unsuffixed floating-point literal.
+    ///
+    /// This constructor is similar to those like `Literal::i8_unsuffixed` where
+    /// the float's value is emitted directly into the token but no suffix is
+    /// used, so it may be inferred to be a `f64` later in the compiler.
+    /// Literals created from negative numbers might not survive rountrips through
+    /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
+    ///
+    /// # Panics
+    ///
+    /// This function requires that the specified float is finite, for
+    /// example if it is infinity or NaN this function will panic.
+    pub fn f64_unsuffixed(n: f64) -> Literal {
+        if !n.is_finite() {
+            panic!("Invalid float literal {n}");
+        }
+        let mut repr = n.to_string();
+        if !repr.contains('.') {
+            repr.push_str(".0");
+        }
+        Literal(bridge::client::Literal::float(&repr))
+    }
+
+    /// Creates a new suffixed floating-point literal.
+    ///
+    /// This constructor will create a literal like `1.0f64` where the value
+    /// specified is the preceding part of the token and `f64` is the suffix of
+    /// the token. This token will always be inferred to be an `f64` in the
+    /// compiler.
+    /// Literals created from negative numbers might not survive rountrips through
+    /// `TokenStream` or strings and may be broken into two tokens (`-` and positive literal).
+    ///
+    /// # Panics
+    ///
+    /// This function requires that the specified float is finite, for
+    /// example if it is infinity or NaN this function will panic.
+    pub fn f64_suffixed(n: f64) -> Literal {
+        if !n.is_finite() {
+            panic!("Invalid float literal {n}");
+        }
+        Literal(bridge::client::Literal::f64(&n.to_string()))
+    }
+
+    /// String literal.
+    pub fn string(string: &str) -> Literal {
+        Literal(bridge::client::Literal::string(string))
+    }
+
+    /// Character literal.
+    pub fn character(ch: char) -> Literal {
+        Literal(bridge::client::Literal::character(ch))
+    }
+
+    /// Byte string literal.
+    pub fn byte_string(bytes: &[u8]) -> Literal {
+        Literal(bridge::client::Literal::byte_string(bytes))
+    }
+
+    /// Returns the span encompassing this literal.
+    pub fn span(&self) -> Span {
+        Span(self.0.span())
+    }
+
+    /// Configures the span associated for this literal.
+    pub fn set_span(&mut self, span: Span) {
+        self.0.set_span(span.0);
+    }
+
+    /// Returns a `Span` that is a subset of `self.span()` containing only the
+    /// source bytes in range `range`. Returns `None` if the would-be trimmed
+    /// span is outside the bounds of `self`.
+    // FIXME(SergioBenitez): check that the byte range starts and ends at a
+    // UTF-8 boundary of the source. otherwise, it's likely that a panic will
+    // occur elsewhere when the source text is printed.
+    // FIXME(SergioBenitez): there is no way for the user to know what
+    // `self.span()` actually maps to, so this method can currently only be
+    // called blindly. For example, `to_string()` for the character 'c' returns
+    // "'\u{63}'"; there is no way for the user to know whether the source text
+    // was 'c' or whether it was '\u{63}'.
+    pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
+        self.0.subspan(range.start_bound().cloned(), range.end_bound().cloned()).map(Span)
+    }
+}
+
+/// Parse a single literal from its stringified representation.
+///
+/// In order to parse successfully, the input string must not contain anything
+/// but the literal token. Specifically, it must not contain whitespace or
+/// comments in addition to the literal.
+///
+/// The resulting literal token will have a `Span::call_site()` span.
+///
+/// NOTE: some errors may cause panics instead of returning `LexError`. We
+/// reserve the right to change these errors into `LexError`s later.
+impl FromStr for Literal {
+    type Err = LexError;
+
+    fn from_str(src: &str) -> Result<Self, LexError> {
+        match bridge::client::Literal::from_str(src) {
+            Ok(literal) => Ok(Literal(literal)),
+            Err(()) => Err(LexError),
+        }
+    }
+}
+
+/// Prints the literal as a string that should be losslessly convertible
+/// back into the same literal (except for possible rounding for floating point literals).
+impl fmt::Display for Literal {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+impl fmt::Debug for Literal {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+/// Tracked access to environment variables.
+pub mod tracked_env {
+    use std::env::{self, VarError};
+    use std::ffi::OsStr;
+
+    /// Retrieve an environment variable and add it to build dependency info.
+    /// Build system executing the compiler will know that the variable was accessed during
+    /// compilation, and will be able to rerun the build when the value of that variable changes.
+    /// Besides the dependency tracking this function should be equivalent to `env::var` from the
+    /// standard library, except that the argument must be UTF-8.
+    pub fn var<K: AsRef<OsStr> + AsRef<str>>(key: K) -> Result<String, VarError> {
+        let key: &str = key.as_ref();
+        let value = env::var(key);
+        super::bridge::client::FreeFunctions::track_env_var(key, value.as_deref().ok());
+        value
+    }
+}
+
+/// Tracked access to additional files.
+pub mod tracked_path {
+
+    /// Track a file explicitly.
+    ///
+    /// Commonly used for tracking asset preprocessing.
+    pub fn path<P: AsRef<str>>(path: P) {
+        let path: &str = path.as_ref();
+        super::bridge::client::FreeFunctions::track_path(path);
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/quote.rs b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/quote.rs
new file mode 100644
index 0000000000..39309faa41
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/proc_macro/quote.rs
@@ -0,0 +1,139 @@
+//! # Quasiquoter
+//! This file contains the implementation internals of the quasiquoter provided by `quote!`.
+
+//! This quasiquoter uses macros 2.0 hygiene to reliably access
+//! items from `proc_macro`, to build a `proc_macro::TokenStream`.
+
+use super::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
+
+macro_rules! quote_tt {
+    (($($t:tt)*)) => { Group::new(Delimiter::Parenthesis, quote!($($t)*)) };
+    ([$($t:tt)*]) => { Group::new(Delimiter::Bracket, quote!($($t)*)) };
+    ({$($t:tt)*}) => { Group::new(Delimiter::Brace, quote!($($t)*)) };
+    (,) => { Punct::new(',', Spacing::Alone) };
+    (.) => { Punct::new('.', Spacing::Alone) };
+    (;) => { Punct::new(';', Spacing::Alone) };
+    (!) => { Punct::new('!', Spacing::Alone) };
+    (<) => { Punct::new('<', Spacing::Alone) };
+    (>) => { Punct::new('>', Spacing::Alone) };
+    (&) => { Punct::new('&', Spacing::Alone) };
+    (=) => { Punct::new('=', Spacing::Alone) };
+    ($i:ident) => { Ident::new(stringify!($i), Span::def_site()) };
+}
+
+macro_rules! quote_ts {
+    ((@ $($t:tt)*)) => { $($t)* };
+    (::) => {
+        [
+            TokenTree::from(Punct::new(':', Spacing::Joint)),
+            TokenTree::from(Punct::new(':', Spacing::Alone)),
+        ].iter()
+            .cloned()
+            .map(|mut x| {
+                x.set_span(Span::def_site());
+                x
+            })
+            .collect::<TokenStream>()
+    };
+    ($t:tt) => { TokenTree::from(quote_tt!($t)) };
+}
+
+/// Simpler version of the real `quote!` macro, implemented solely
+/// through `macro_rules`, for bootstrapping the real implementation
+/// (see the `quote` function), which does not have access to the
+/// real `quote!` macro due to the `proc_macro` crate not being
+/// able to depend on itself.
+///
+/// Note: supported tokens are a subset of the real `quote!`, but
+/// unquoting is different: instead of `$x`, this uses `(@ expr)`.
+macro_rules! quote {
+    () => { TokenStream::new() };
+    ($($t:tt)*) => {
+        [
+            $(TokenStream::from(quote_ts!($t)),)*
+        ].iter().cloned().collect::<TokenStream>()
+    };
+}
+
+/// Quote a `TokenStream` into a `TokenStream`.
+/// This is the actual implementation of the `quote!()` proc macro.
+///
+/// It is loaded by the compiler in `register_builtin_macros`.
+pub fn quote(stream: TokenStream) -> TokenStream {
+    if stream.is_empty() {
+        return quote!(super::TokenStream::new());
+    }
+    let proc_macro_crate = quote!(crate);
+    let mut after_dollar = false;
+    let tokens = stream
+        .into_iter()
+        .filter_map(|tree| {
+            if after_dollar {
+                after_dollar = false;
+                match tree {
+                    TokenTree::Ident(_) => {
+                        return Some(quote!(Into::<super::TokenStream>::into(
+                        Clone::clone(&(@ tree))),));
+                    }
+                    TokenTree::Punct(ref tt) if tt.as_char() == '$' => {}
+                    _ => panic!("`$` must be followed by an ident or `$` in `quote!`"),
+                }
+            } else if let TokenTree::Punct(ref tt) = tree {
+                if tt.as_char() == '$' {
+                    after_dollar = true;
+                    return None;
+                }
+            }
+
+            Some(quote!(super::TokenStream::from((@ match tree {
+                TokenTree::Punct(tt) => quote!(super::TokenTree::Punct(super::Punct::new(
+                    (@ TokenTree::from(Literal::character(tt.as_char()))),
+                    (@ match tt.spacing() {
+                        Spacing::Alone => quote!(super::Spacing::Alone),
+                        Spacing::Joint => quote!(super::Spacing::Joint),
+                    }),
+                ))),
+                TokenTree::Group(tt) => quote!(super::TokenTree::Group(super::Group::new(
+                    (@ match tt.delimiter() {
+                        Delimiter::Parenthesis => quote!(super::Delimiter::Parenthesis),
+                        Delimiter::Brace => quote!(super::Delimiter::Brace),
+                        Delimiter::Bracket => quote!(super::Delimiter::Bracket),
+                        Delimiter::None => quote!(super::Delimiter::None),
+                    }),
+                    (@ quote(tt.stream())),
+                ))),
+                TokenTree::Ident(tt) => quote!(super::TokenTree::Ident(super::Ident::new(
+                    (@ TokenTree::from(Literal::string(&tt.to_string()))),
+                    (@ quote_span(proc_macro_crate.clone(), tt.span())),
+                ))),
+                TokenTree::Literal(tt) => quote!(super::TokenTree::Literal({
+                    let mut iter = (@ TokenTree::from(Literal::string(&tt.to_string())))
+                        .parse::<super::TokenStream>()
+                        .unwrap()
+                        .into_iter();
+                    if let (Some(super::TokenTree::Literal(mut lit)), None) =
+                        (iter.next(), iter.next())
+                    {
+                        lit.set_span((@ quote_span(proc_macro_crate.clone(), tt.span())));
+                        lit
+                    } else {
+                        unreachable!()
+                    }
+                }))
+            })),))
+        })
+        .collect::<TokenStream>();
+
+    if after_dollar {
+        panic!("unexpected trailing `$` in `quote!`");
+    }
+
+    quote!([(@ tokens)].iter().cloned().collect::<super::TokenStream>())
+}
+
+/// Quote a `Span` into a `TokenStream`.
+/// This is needed to implement a custom quoter.
+pub fn quote_span(proc_macro_crate: TokenStream, span: Span) -> TokenStream {
+    let id = span.save_span();
+    quote!((@ proc_macro_crate ) ::Span::recover_proc_macro_span((@ TokenTree::from(Literal::usize_unsuffixed(id)))))
+}
diff --git a/crates/proc-macro-srv/src/abis/abi_1_64/ra_server.rs b/crates/proc-macro-srv/src/abis/abi_1_64/ra_server.rs
new file mode 100644
index 0000000000..d8aa1ec429
--- /dev/null
+++ b/crates/proc-macro-srv/src/abis/abi_1_64/ra_server.rs
@@ -0,0 +1,791 @@
+//! Rustc proc-macro server implementation with tt
+//!
+//! Based on idea from <https://github.com/fedochet/rust-proc-macro-expander>
+//! The lib-proc-macro server backend is `TokenStream`-agnostic, such that
+//! we could provide any TokenStream implementation.
+//! The original idea from fedochet is using proc-macro2 as backend,
+//! we use tt instead for better integration with RA.
+//!
+//! FIXME: No span and source file information is implemented yet
+
+use super::proc_macro::bridge::{self, server};
+
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::ops::Bound;
+use std::{ascii, vec::IntoIter};
+
+type Group = tt::Subtree;
+type TokenTree = tt::TokenTree;
+type Punct = tt::Punct;
+type Spacing = tt::Spacing;
+type Literal = tt::Literal;
+type Span = tt::TokenId;
+
+#[derive(Debug, Default, Clone)]
+pub struct TokenStream {
+    pub token_trees: Vec<TokenTree>,
+}
+
+impl TokenStream {
+    pub fn new() -> Self {
+        TokenStream::default()
+    }
+
+    pub fn with_subtree(subtree: tt::Subtree) -> Self {
+        if subtree.delimiter.is_some() {
+            TokenStream { token_trees: vec![TokenTree::Subtree(subtree)] }
+        } else {
+            TokenStream { token_trees: subtree.token_trees }
+        }
+    }
+
+    pub fn into_subtree(self) -> tt::Subtree {
+        tt::Subtree { delimiter: None, token_trees: self.token_trees }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.token_trees.is_empty()
+    }
+}
+
+/// Creates a token stream containing a single token tree.
+impl From<TokenTree> for TokenStream {
+    fn from(tree: TokenTree) -> TokenStream {
+        TokenStream { token_trees: vec![tree] }
+    }
+}
+
+/// Collects a number of token trees into a single stream.
+impl FromIterator<TokenTree> for TokenStream {
+    fn from_iter<I: IntoIterator<Item = TokenTree>>(trees: I) -> Self {
+        trees.into_iter().map(TokenStream::from).collect()
+    }
+}
+
+/// A "flattening" operation on token streams, collects token trees
+/// from multiple token streams into a single stream.
+impl FromIterator<TokenStream> for TokenStream {
+    fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
+        let mut builder = TokenStreamBuilder::new();
+        streams.into_iter().for_each(|stream| builder.push(stream));
+        builder.build()
+    }
+}
+
+impl Extend<TokenTree> for TokenStream {
+    fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, trees: I) {
+        self.extend(trees.into_iter().map(TokenStream::from));
+    }
+}
+
+impl Extend<TokenStream> for TokenStream {
+    fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
+        for item in streams {
+            for tkn in item {
+                match tkn {
+                    tt::TokenTree::Subtree(subtree) if subtree.delimiter.is_none() => {
+                        self.token_trees.extend(subtree.token_trees);
+                    }
+                    _ => {
+                        self.token_trees.push(tkn);
+                    }
+                }
+            }
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct SourceFile {
+    // FIXME stub
+}
+
+type Level = super::proc_macro::Level;
+type LineColumn = super::proc_macro::LineColumn;
+
+/// A structure representing a diagnostic message and associated children
+/// messages.
+#[derive(Clone, Debug)]
+pub struct Diagnostic {
+    level: Level,
+    message: String,
+    spans: Vec<Span>,
+    children: Vec<Diagnostic>,
+}
+
+impl Diagnostic {
+    /// Creates a new diagnostic with the given `level` and `message`.
+    pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
+        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
+    }
+}
+
+// Rustc Server Ident has to be `Copyable`
+// We use a stub here for bypassing
+#[derive(Hash, Eq, PartialEq, Copy, Clone)]
+pub struct IdentId(u32);
+
+#[derive(Clone, Hash, Eq, PartialEq)]
+struct IdentData(tt::Ident);
+
+#[derive(Default)]
+struct IdentInterner {
+    idents: HashMap<IdentData, u32>,
+    ident_data: Vec<IdentData>,
+}
+
+impl IdentInterner {
+    fn intern(&mut self, data: &IdentData) -> u32 {
+        if let Some(index) = self.idents.get(data) {
+            return *index;
+        }
+
+        let index = self.idents.len() as u32;
+        self.ident_data.push(data.clone());
+        self.idents.insert(data.clone(), index);
+        index
+    }
+
+    fn get(&self, index: u32) -> &IdentData {
+        &self.ident_data[index as usize]
+    }
+
+    #[allow(unused)]
+    fn get_mut(&mut self, index: u32) -> &mut IdentData {
+        self.ident_data.get_mut(index as usize).expect("Should be consistent")
+    }
+}
+
+pub struct TokenStreamBuilder {
+    acc: TokenStream,
+}
+
+/// Public implementation details for the `TokenStream` type, such as iterators.
+pub mod token_stream {
+    use std::str::FromStr;
+
+    use super::{TokenStream, TokenTree};
+
+    /// An iterator over `TokenStream`'s `TokenTree`s.
+    /// The iteration is "shallow", e.g., the iterator doesn't recurse into delimited groups,
+    /// and returns whole groups as token trees.
+    impl IntoIterator for TokenStream {
+        type Item = TokenTree;
+        type IntoIter = super::IntoIter<TokenTree>;
+
+        fn into_iter(self) -> Self::IntoIter {
+            self.token_trees.into_iter()
+        }
+    }
+
+    type LexError = String;
+
+    /// Attempts to break the string into tokens and parse those tokens into a token stream.
+    /// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
+    /// or characters not existing in the language.
+    /// All tokens in the parsed stream get `Span::call_site()` spans.
+    ///
+    /// NOTE: some errors may cause panics instead of returning `LexError`. We reserve the right to
+    /// change these errors into `LexError`s later.
+    impl FromStr for TokenStream {
+        type Err = LexError;
+
+        fn from_str(src: &str) -> Result<TokenStream, LexError> {
+            let (subtree, _token_map) =
+                mbe::parse_to_token_tree(src).ok_or("Failed to parse from mbe")?;
+
+            let subtree = subtree_replace_token_ids_with_unspecified(subtree);
+            Ok(TokenStream::with_subtree(subtree))
+        }
+    }
+
+    impl ToString for TokenStream {
+        fn to_string(&self) -> String {
+            tt::pretty(&self.token_trees)
+        }
+    }
+
+    fn subtree_replace_token_ids_with_unspecified(subtree: tt::Subtree) -> tt::Subtree {
+        tt::Subtree {
+            delimiter: subtree
+                .delimiter
+                .map(|d| tt::Delimiter { id: tt::TokenId::unspecified(), ..d }),
+            token_trees: subtree
+                .token_trees
+                .into_iter()
+                .map(token_tree_replace_token_ids_with_unspecified)
+                .collect(),
+        }
+    }
+
+    fn token_tree_replace_token_ids_with_unspecified(tt: tt::TokenTree) -> tt::TokenTree {
+        match tt {
+            tt::TokenTree::Leaf(leaf) => {
+                tt::TokenTree::Leaf(leaf_replace_token_ids_with_unspecified(leaf))
+            }
+            tt::TokenTree::Subtree(subtree) => {
+                tt::TokenTree::Subtree(subtree_replace_token_ids_with_unspecified(subtree))
+            }
+        }
+    }
+
+    fn leaf_replace_token_ids_with_unspecified(leaf: tt::Leaf) -> tt::Leaf {
+        match leaf {
+            tt::Leaf::Literal(lit) => {
+                tt::Leaf::Literal(tt::Literal { id: tt::TokenId::unspecified(), ..lit })
+            }
+            tt::Leaf::Punct(punct) => {
+                tt::Leaf::Punct(tt::Punct { id: tt::TokenId::unspecified(), ..punct })
+            }
+            tt::Leaf::Ident(ident) => {
+                tt::Leaf::Ident(tt::Ident { id: tt::TokenId::unspecified(), ..ident })
+            }
+        }
+    }
+}
+
+impl TokenStreamBuilder {
+    fn new() -> TokenStreamBuilder {
+        TokenStreamBuilder { acc: TokenStream::new() }
+    }
+
+    fn push(&mut self, stream: TokenStream) {
+        self.acc.extend(stream.into_iter())
+    }
+
+    fn build(self) -> TokenStream {
+        self.acc
+    }
+}
+
+pub struct FreeFunctions;
+
+#[derive(Clone)]
+pub struct TokenStreamIter {
+    trees: IntoIter<TokenTree>,
+}
+
+#[derive(Default)]
+pub struct RustAnalyzer {
+    ident_interner: IdentInterner,
+    // FIXME: store span information here.
+}
+
+impl server::Types for RustAnalyzer {
+    type FreeFunctions = FreeFunctions;
+    type TokenStream = TokenStream;
+    type Ident = IdentId;
+    type Literal = Literal;
+    type SourceFile = SourceFile;
+    type Diagnostic = Diagnostic;
+    type Span = Span;
+    type MultiSpan = Vec<Span>;
+}
+
+impl server::FreeFunctions for RustAnalyzer {
+    fn track_env_var(&mut self, _var: &str, _value: Option<&str>) {
+        // FIXME: track env var accesses
+        // https://github.com/rust-lang/rust/pull/71858
+    }
+    fn track_path(&mut self, _path: &str) {}
+}
+
+impl server::TokenStream for RustAnalyzer {
+    fn is_empty(&mut self, stream: &Self::TokenStream) -> bool {
+        stream.is_empty()
+    }
+    fn from_str(&mut self, src: &str) -> Self::TokenStream {
+        use std::str::FromStr;
+
+        Self::TokenStream::from_str(src).expect("cannot parse string")
+    }
+    fn to_string(&mut self, stream: &Self::TokenStream) -> String {
+        stream.to_string()
+    }
+    fn from_token_tree(
+        &mut self,
+        tree: bridge::TokenTree<Self::TokenStream, Self::Span, Self::Ident, Self::Literal>,
+    ) -> Self::TokenStream {
+        match tree {
+            bridge::TokenTree::Group(group) => {
+                let group = Group {
+                    delimiter: delim_to_internal(group.delimiter),
+                    token_trees: match group.stream {
+                        Some(stream) => stream.into_iter().collect(),
+                        None => Vec::new(),
+                    },
+                };
+                let tree = TokenTree::from(group);
+                Self::TokenStream::from_iter(vec![tree])
+            }
+
+            bridge::TokenTree::Ident(IdentId(index)) => {
+                let IdentData(ident) = self.ident_interner.get(index).clone();
+                let ident: tt::Ident = ident;
+                let leaf = tt::Leaf::from(ident);
+                let tree = TokenTree::from(leaf);
+                Self::TokenStream::from_iter(vec![tree])
+            }
+
+            bridge::TokenTree::Literal(literal) => {
+                let leaf = tt::Leaf::from(literal);
+                let tree = TokenTree::from(leaf);
+                Self::TokenStream::from_iter(vec![tree])
+            }
+
+            bridge::TokenTree::Punct(p) => {
+                let punct = tt::Punct {
+                    char: p.ch as char,
+                    spacing: if p.joint { Spacing::Joint } else { Spacing::Alone },
+                    id: p.span,
+                };
+                let leaf = tt::Leaf::from(punct);
+                let tree = TokenTree::from(leaf);
+                Self::TokenStream::from_iter(vec![tree])
+            }
+        }
+    }
+
+    fn expand_expr(&mut self, self_: &Self::TokenStream) -> Result<Self::TokenStream, ()> {
+        Ok(self_.clone())
+    }
+
+    fn concat_trees(
+        &mut self,
+        base: Option<Self::TokenStream>,
+        trees: Vec<bridge::TokenTree<Self::TokenStream, Self::Span, Self::Ident, Self::Literal>>,
+    ) -> Self::TokenStream {
+        let mut builder = TokenStreamBuilder::new();
+        if let Some(base) = base {
+            builder.push(base);
+        }
+        for tree in trees {
+            builder.push(self.from_token_tree(tree));
+        }
+        builder.build()
+    }
+
+    fn concat_streams(
+        &mut self,
+        base: Option<Self::TokenStream>,
+        streams: Vec<Self::TokenStream>,
+    ) -> Self::TokenStream {
+        let mut builder = TokenStreamBuilder::new();
+        if let Some(base) = base {
+            builder.push(base);
+        }
+        for stream in streams {
+            builder.push(stream);
+        }
+        builder.build()
+    }
+
+    fn into_trees(
+        &mut self,
+        stream: Self::TokenStream,
+    ) -> Vec<bridge::TokenTree<Self::TokenStream, Self::Span, Self::Ident, Self::Literal>> {
+        stream
+            .into_iter()
+            .map(|tree| match tree {
+                tt::TokenTree::Leaf(tt::Leaf::Ident(ident)) => {
+                    bridge::TokenTree::Ident(IdentId(self.ident_interner.intern(&IdentData(ident))))
+                }
+                tt::TokenTree::Leaf(tt::Leaf::Literal(lit)) => bridge::TokenTree::Literal(lit),
+                tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) => {
+                    bridge::TokenTree::Punct(bridge::Punct {
+                        ch: punct.char as u8,
+                        joint: punct.spacing == Spacing::Joint,
+                        span: punct.id,
+                    })
+                }
+                tt::TokenTree::Subtree(subtree) => bridge::TokenTree::Group(bridge::Group {
+                    delimiter: delim_to_external(subtree.delimiter),
+                    stream: if subtree.token_trees.is_empty() {
+                        None
+                    } else {
+                        Some(subtree.token_trees.into_iter().collect())
+                    },
+                    span: bridge::DelimSpan::from_single(
+                        subtree.delimiter.map_or(Span::unspecified(), |del| del.id),
+                    ),
+                }),
+            })
+            .collect()
+    }
+}
+
+fn delim_to_internal(d: bridge::Delimiter) -> Option<tt::Delimiter> {
+    let kind = match d {
+        bridge::Delimiter::Parenthesis => tt::DelimiterKind::Parenthesis,
+        bridge::Delimiter::Brace => tt::DelimiterKind::Brace,
+        bridge::Delimiter::Bracket => tt::DelimiterKind::Bracket,
+        bridge::Delimiter::None => return None,
+    };
+    Some(tt::Delimiter { id: tt::TokenId::unspecified(), kind })
+}
+
+fn delim_to_external(d: Option<tt::Delimiter>) -> bridge::Delimiter {
+    match d.map(|it| it.kind) {
+        Some(tt::DelimiterKind::Parenthesis) => bridge::Delimiter::Parenthesis,
+        Some(tt::DelimiterKind::Brace) => bridge::Delimiter::Brace,
+        Some(tt::DelimiterKind::Bracket) => bridge::Delimiter::Bracket,
+        None => bridge::Delimiter::None,
+    }
+}
+
+fn spacing_to_internal(spacing: bridge::Spacing) -> Spacing {
+    match spacing {
+        bridge::Spacing::Alone => Spacing::Alone,
+        bridge::Spacing::Joint => Spacing::Joint,
+    }
+}
+
+fn spacing_to_external(spacing: Spacing) -> bridge::Spacing {
+    match spacing {
+        Spacing::Alone => bridge::Spacing::Alone,
+        Spacing::Joint => bridge::Spacing::Joint,
+    }
+}
+
+impl server::Ident for RustAnalyzer {
+    fn new(&mut self, string: &str, span: Self::Span, _is_raw: bool) -> Self::Ident {
+        IdentId(self.ident_interner.intern(&IdentData(tt::Ident { text: string.into(), id: span })))
+    }
+
+    fn span(&mut self, ident: Self::Ident) -> Self::Span {
+        self.ident_interner.get(ident.0).0.id
+    }
+    fn with_span(&mut self, ident: Self::Ident, span: Self::Span) -> Self::Ident {
+        let data = self.ident_interner.get(ident.0);
+        let new = IdentData(tt::Ident { id: span, ..data.0.clone() });
+        IdentId(self.ident_interner.intern(&new))
+    }
+}
+
+impl server::Literal for RustAnalyzer {
+    fn debug_kind(&mut self, _literal: &Self::Literal) -> String {
+        // r-a: debug_kind and suffix are unsupported; corresponding client code has been changed to not call these.
+        // They must still be present to be ABI-compatible and work with upstream proc_macro.
+        "".to_owned()
+    }
+    fn from_str(&mut self, s: &str) -> Result<Self::Literal, ()> {
+        Ok(Literal { text: s.into(), id: tt::TokenId::unspecified() })
+    }
+    fn symbol(&mut self, literal: &Self::Literal) -> String {
+        literal.text.to_string()
+    }
+    fn suffix(&mut self, _literal: &Self::Literal) -> Option<String> {
+        None
+    }
+
+    fn to_string(&mut self, literal: &Self::Literal) -> String {
+        literal.to_string()
+    }
+
+    fn integer(&mut self, n: &str) -> Self::Literal {
+        let n = match n.parse::<i128>() {
+            Ok(n) => n.to_string(),
+            Err(_) => n.parse::<u128>().unwrap().to_string(),
+        };
+        Literal { text: n.into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn typed_integer(&mut self, n: &str, kind: &str) -> Self::Literal {
+        macro_rules! def_suffixed_integer {
+            ($kind:ident, $($ty:ty),*) => {
+                match $kind {
+                    $(
+                        stringify!($ty) => {
+                            let n: $ty = n.parse().unwrap();
+                            format!(concat!("{}", stringify!($ty)), n)
+                        }
+                    )*
+                    _ => unimplemented!("unknown args for typed_integer: n {}, kind {}", n, $kind),
+                }
+            }
+        }
+
+        let text = def_suffixed_integer! {kind, u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize};
+
+        Literal { text: text.into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn float(&mut self, n: &str) -> Self::Literal {
+        let n: f64 = n.parse().unwrap();
+        let mut text = f64::to_string(&n);
+        if !text.contains('.') {
+            text += ".0"
+        }
+        Literal { text: text.into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn f32(&mut self, n: &str) -> Self::Literal {
+        let n: f32 = n.parse().unwrap();
+        let text = format!("{}f32", n);
+        Literal { text: text.into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn f64(&mut self, n: &str) -> Self::Literal {
+        let n: f64 = n.parse().unwrap();
+        let text = format!("{}f64", n);
+        Literal { text: text.into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn string(&mut self, string: &str) -> Self::Literal {
+        let mut escaped = String::new();
+        for ch in string.chars() {
+            escaped.extend(ch.escape_debug());
+        }
+        Literal { text: format!("\"{}\"", escaped).into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn character(&mut self, ch: char) -> Self::Literal {
+        Literal { text: format!("'{}'", ch).into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn byte_string(&mut self, bytes: &[u8]) -> Self::Literal {
+        let string = bytes
+            .iter()
+            .cloned()
+            .flat_map(ascii::escape_default)
+            .map(Into::<char>::into)
+            .collect::<String>();
+
+        Literal { text: format!("b\"{}\"", string).into(), id: tt::TokenId::unspecified() }
+    }
+
+    fn span(&mut self, literal: &Self::Literal) -> Self::Span {
+        literal.id
+    }
+
+    fn set_span(&mut self, literal: &mut Self::Literal, span: Self::Span) {
+        literal.id = span;
+    }
+
+    fn subspan(
+        &mut self,
+        _literal: &Self::Literal,
+        _start: Bound<usize>,
+        _end: Bound<usize>,
+    ) -> Option<Self::Span> {
+        // FIXME handle span
+        None
+    }
+}
+
+impl server::SourceFile for RustAnalyzer {
+    // FIXME these are all stubs
+    fn eq(&mut self, _file1: &Self::SourceFile, _file2: &Self::SourceFile) -> bool {
+        true
+    }
+    fn path(&mut self, _file: &Self::SourceFile) -> String {
+        String::new()
+    }
+    fn is_real(&mut self, _file: &Self::SourceFile) -> bool {
+        true
+    }
+}
+
+impl server::Diagnostic for RustAnalyzer {
+    fn new(&mut self, level: Level, msg: &str, spans: Self::MultiSpan) -> Self::Diagnostic {
+        let mut diag = Diagnostic::new(level, msg);
+        diag.spans = spans;
+        diag
+    }
+
+    fn sub(
+        &mut self,
+        _diag: &mut Self::Diagnostic,
+        _level: Level,
+        _msg: &str,
+        _spans: Self::MultiSpan,
+    ) {
+        // FIXME handle diagnostic
+        //
+    }
+
+    fn emit(&mut self, _diag: Self::Diagnostic) {
+        // FIXME handle diagnostic
+        // diag.emit()
+    }
+}
+
+impl server::Span for RustAnalyzer {
+    fn debug(&mut self, span: Self::Span) -> String {
+        format!("{:?}", span.0)
+    }
+    fn source_file(&mut self, _span: Self::Span) -> Self::SourceFile {
+        SourceFile {}
+    }
+    fn save_span(&mut self, _span: Self::Span) -> usize {
+        // FIXME stub
+        0
+    }
+    fn recover_proc_macro_span(&mut self, _id: usize) -> Self::Span {
+        // FIXME stub
+        tt::TokenId::unspecified()
+    }
+    /// Recent feature, not yet in the proc_macro
+    ///
+    /// See PR:
+    /// https://github.com/rust-lang/rust/pull/55780
+    fn source_text(&mut self, _span: Self::Span) -> Option<String> {
+        None
+    }
+
+    fn parent(&mut self, _span: Self::Span) -> Option<Self::Span> {
+        // FIXME handle span
+        None
+    }
+    fn source(&mut self, span: Self::Span) -> Self::Span {
+        // FIXME handle span
+        span
+    }
+    fn start(&mut self, _span: Self::Span) -> LineColumn {
+        // FIXME handle span
+        LineColumn { line: 0, column: 0 }
+    }
+    fn end(&mut self, _span: Self::Span) -> LineColumn {
+        // FIXME handle span
+        LineColumn { line: 0, column: 0 }
+    }
+    fn join(&mut self, first: Self::Span, _second: Self::Span) -> Option<Self::Span> {
+        // Just return the first span again, because some macros will unwrap the result.
+        Some(first)
+    }
+    fn resolved_at(&mut self, _span: Self::Span, _at: Self::Span) -> Self::Span {
+        // FIXME handle span
+        tt::TokenId::unspecified()
+    }
+
+    fn after(&mut self, _self_: Self::Span) -> Self::Span {
+        tt::TokenId::unspecified()
+    }
+
+    fn before(&mut self, _self_: Self::Span) -> Self::Span {
+        tt::TokenId::unspecified()
+    }
+}
+
+impl server::MultiSpan for RustAnalyzer {
+    fn new(&mut self) -> Self::MultiSpan {
+        // FIXME handle span
+        vec![]
+    }
+
+    fn push(&mut self, other: &mut Self::MultiSpan, span: Self::Span) {
+        //TODP
+        other.push(span)
+    }
+}
+
+impl server::Server for RustAnalyzer {
+    fn globals(&mut self) -> bridge::ExpnGlobals<Self::Span> {
+        bridge::ExpnGlobals {
+            def_site: Span::unspecified(),
+            call_site: Span::unspecified(),
+            mixed_site: Span::unspecified(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::super::proc_macro::bridge::server::Literal;
+    use super::*;
+
+    #[test]
+    fn test_ra_server_literals() {
+        let mut srv = RustAnalyzer { ident_interner: IdentInterner::default() };
+        assert_eq!(srv.integer("1234").text, "1234");
+
+        assert_eq!(srv.typed_integer("12", "u8").text, "12u8");
+        assert_eq!(srv.typed_integer("255", "u16").text, "255u16");
+        assert_eq!(srv.typed_integer("1234", "u32").text, "1234u32");
+        assert_eq!(srv.typed_integer("15846685", "u64").text, "15846685u64");
+        assert_eq!(srv.typed_integer("15846685258", "u128").text, "15846685258u128");
+        assert_eq!(srv.typed_integer("156788984", "usize").text, "156788984usize");
+        assert_eq!(srv.typed_integer("127", "i8").text, "127i8");
+        assert_eq!(srv.typed_integer("255", "i16").text, "255i16");
+        assert_eq!(srv.typed_integer("1234", "i32").text, "1234i32");
+        assert_eq!(srv.typed_integer("15846685", "i64").text, "15846685i64");
+        assert_eq!(srv.typed_integer("15846685258", "i128").text, "15846685258i128");
+        assert_eq!(srv.float("0").text, "0.0");
+        assert_eq!(srv.float("15684.5867").text, "15684.5867");
+        assert_eq!(srv.f32("15684.58").text, "15684.58f32");
+        assert_eq!(srv.f64("15684.58").text, "15684.58f64");
+
+        assert_eq!(srv.string("hello_world").text, "\"hello_world\"");
+        assert_eq!(srv.character('c').text, "'c'");
+        assert_eq!(srv.byte_string(b"1234586\x88").text, "b\"1234586\\x88\"");
+
+        // u128::max
+        assert_eq!(
+            srv.integer("340282366920938463463374607431768211455").text,
+            "340282366920938463463374607431768211455"
+        );
+        // i128::min
+        assert_eq!(
+            srv.integer("-170141183460469231731687303715884105728").text,
+            "-170141183460469231731687303715884105728"
+        );
+    }
+
+    #[test]
+    fn test_ra_server_to_string() {
+        let s = TokenStream {
+            token_trees: vec![
+                tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                    text: "struct".into(),
+                    id: tt::TokenId::unspecified(),
+                })),
+                tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                    text: "T".into(),
+                    id: tt::TokenId::unspecified(),
+                })),
+                tt::TokenTree::Subtree(tt::Subtree {
+                    delimiter: Some(tt::Delimiter {
+                        id: tt::TokenId::unspecified(),
+                        kind: tt::DelimiterKind::Brace,
+                    }),
+                    token_trees: vec![],
+                }),
+            ],
+        };
+
+        assert_eq!(s.to_string(), "struct T {}");
+    }
+
+    #[test]
+    fn test_ra_server_from_str() {
+        use std::str::FromStr;
+        let subtree_paren_a = tt::TokenTree::Subtree(tt::Subtree {
+            delimiter: Some(tt::Delimiter {
+                id: tt::TokenId::unspecified(),
+                kind: tt::DelimiterKind::Parenthesis,
+            }),
+            token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                text: "a".into(),
+                id: tt::TokenId::unspecified(),
+            }))],
+        });
+
+        let t1 = TokenStream::from_str("(a)").unwrap();
+        assert_eq!(t1.token_trees.len(), 1);
+        assert_eq!(t1.token_trees[0], subtree_paren_a);
+
+        let t2 = TokenStream::from_str("(a);").unwrap();
+        assert_eq!(t2.token_trees.len(), 2);
+        assert_eq!(t2.token_trees[0], subtree_paren_a);
+
+        let underscore = TokenStream::from_str("_").unwrap();
+        assert_eq!(
+            underscore.token_trees[0],
+            tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident {
+                text: "_".into(),
+                id: tt::TokenId::unspecified(),
+            }))
+        );
+    }
+}
diff --git a/crates/proc-macro-srv/src/abis/mod.rs b/crates/proc-macro-srv/src/abis/mod.rs
index f7d3a30919..705d09ea94 100644
--- a/crates/proc-macro-srv/src/abis/mod.rs
+++ b/crates/proc-macro-srv/src/abis/mod.rs
@@ -25,6 +25,7 @@
 
 mod abi_1_58;
 mod abi_1_63;
+mod abi_1_64;
 #[cfg(feature = "sysroot-abi")]
 mod abi_sysroot;
 
@@ -33,11 +34,12 @@ include!(concat!(env!("OUT_DIR"), "/rustc_version.rs"));
 
 // Used by `test/utils.rs`
 #[cfg(test)]
-pub(crate) use abi_1_63::TokenStream as TestTokenStream;
+pub(crate) use abi_1_64::TokenStream as TestTokenStream;
 
 use super::dylib::LoadProcMacroDylibError;
 pub(crate) use abi_1_58::Abi as Abi_1_58;
 pub(crate) use abi_1_63::Abi as Abi_1_63;
+pub(crate) use abi_1_64::Abi as Abi_1_64;
 #[cfg(feature = "sysroot-abi")]
 pub(crate) use abi_sysroot::Abi as Abi_Sysroot;
 use libloading::Library;
@@ -56,6 +58,7 @@ impl PanicMessage {
 pub(crate) enum Abi {
     Abi1_58(Abi_1_58),
     Abi1_63(Abi_1_63),
+    Abi1_64(Abi_1_64),
     #[cfg(feature = "sysroot-abi")]
     AbiSysroot(Abi_Sysroot),
 }
@@ -117,6 +120,10 @@ impl Abi {
                 let inner = unsafe { Abi_1_63::from_lib(lib, symbol_name) }?;
                 Ok(Abi::Abi1_63(inner))
             }
+            (1, 64..) => {
+                let inner = unsafe { Abi_1_64::from_lib(lib, symbol_name) }?;
+                Ok(Abi::Abi1_64(inner))
+            }
             _ => Err(LoadProcMacroDylibError::UnsupportedABI),
         }
     }
@@ -130,6 +137,7 @@ impl Abi {
         match self {
             Self::Abi1_58(abi) => abi.expand(macro_name, macro_body, attributes),
             Self::Abi1_63(abi) => abi.expand(macro_name, macro_body, attributes),
+            Self::Abi1_64(abi) => abi.expand(macro_name, macro_body, attributes),
             #[cfg(feature = "sysroot-abi")]
             Self::AbiSysroot(abi) => abi.expand(macro_name, macro_body, attributes),
         }
@@ -139,6 +147,7 @@ impl Abi {
         match self {
             Self::Abi1_58(abi) => abi.list_macros(),
             Self::Abi1_63(abi) => abi.list_macros(),
+            Self::Abi1_64(abi) => abi.list_macros(),
             #[cfg(feature = "sysroot-abi")]
             Self::AbiSysroot(abi) => abi.list_macros(),
         }
diff --git a/crates/project-model/src/build_scripts.rs b/crates/project-model/src/build_scripts.rs
index 84e772d168..ee7f8339a7 100644
--- a/crates/project-model/src/build_scripts.rs
+++ b/crates/project-model/src/build_scripts.rs
@@ -12,7 +12,6 @@ use cargo_metadata::{camino::Utf8Path, Message};
 use la_arena::ArenaMap;
 use paths::AbsPathBuf;
 use rustc_hash::FxHashMap;
-use semver::Version;
 use serde::Deserialize;
 
 use crate::{cfg_flag::CfgFlag, CargoConfig, CargoWorkspace, Package};
@@ -78,32 +77,9 @@ impl WorkspaceBuildScripts {
         config: &CargoConfig,
         workspace: &CargoWorkspace,
         progress: &dyn Fn(String),
-        toolchain: &Option<Version>,
     ) -> io::Result<WorkspaceBuildScripts> {
-        const RUST_1_62: Version = Version::new(1, 62, 0);
+        let mut cmd = Self::build_command(config);
 
-        match Self::run_(Self::build_command(config), config, workspace, progress) {
-            Ok(WorkspaceBuildScripts { error: Some(error), .. })
-                if toolchain.as_ref().map_or(false, |it| *it >= RUST_1_62) =>
-            {
-                // building build scripts failed, attempt to build with --keep-going so
-                // that we potentially get more build data
-                let mut cmd = Self::build_command(config);
-                cmd.args(&["-Z", "unstable-options", "--keep-going"]).env("RUSTC_BOOTSTRAP", "1");
-                let mut res = Self::run_(cmd, config, workspace, progress)?;
-                res.error = Some(error);
-                Ok(res)
-            }
-            res => res,
-        }
-    }
-
-    fn run_(
-        mut cmd: Command,
-        config: &CargoConfig,
-        workspace: &CargoWorkspace,
-        progress: &dyn Fn(String),
-    ) -> io::Result<WorkspaceBuildScripts> {
         if config.wrap_rustc_in_build_scripts {
             // Setup RUSTC_WRAPPER to point to `rust-analyzer` binary itself. We use
             // that to compile only proc macros and build scripts during the initial
diff --git a/crates/project-model/src/workspace.rs b/crates/project-model/src/workspace.rs
index daabb299f7..b144006b44 100644
--- a/crates/project-model/src/workspace.rs
+++ b/crates/project-model/src/workspace.rs
@@ -12,7 +12,6 @@ use base_db::{
 use cfg::{CfgDiff, CfgOptions};
 use paths::{AbsPath, AbsPathBuf};
 use rustc_hash::{FxHashMap, FxHashSet};
-use semver::Version;
 use stdx::always;
 
 use crate::{
@@ -78,7 +77,6 @@ pub enum ProjectWorkspace {
         /// different target.
         rustc_cfg: Vec<CfgFlag>,
         cfg_overrides: CfgOverrides,
-        toolchain: Option<Version>,
     },
     /// Project workspace was manually specified using a `rust-project.json` file.
     Json { project: ProjectJson, sysroot: Option<Sysroot>, rustc_cfg: Vec<CfgFlag> },
@@ -107,7 +105,6 @@ impl fmt::Debug for ProjectWorkspace {
                 rustc,
                 rustc_cfg,
                 cfg_overrides,
-                toolchain,
             } => f
                 .debug_struct("Cargo")
                 .field("root", &cargo.workspace_root().file_name())
@@ -119,7 +116,6 @@ impl fmt::Debug for ProjectWorkspace {
                 )
                 .field("n_rustc_cfg", &rustc_cfg.len())
                 .field("n_cfg_overrides", &cfg_overrides.len())
-                .field("toolchain", &toolchain)
                 .finish(),
             ProjectWorkspace::Json { project, sysroot, rustc_cfg } => {
                 let mut debug_struct = f.debug_struct("Json");
@@ -164,9 +160,6 @@ impl ProjectWorkspace {
                     cmd.arg("--version");
                     cmd
                 })?;
-                let toolchain = cargo_version
-                    .get("cargo ".len()..)
-                    .and_then(|it| Version::parse(it.split_whitespace().next()?).ok());
 
                 let meta = CargoWorkspace::fetch_metadata(
                     &cargo_toml,
@@ -176,9 +169,9 @@ impl ProjectWorkspace {
                 )
                 .with_context(|| {
                     format!(
-                        "Failed to read Cargo metadata from Cargo.toml file {}, {:?}",
+                        "Failed to read Cargo metadata from Cargo.toml file {}, {}",
                         cargo_toml.display(),
-                        toolchain
+                        cargo_version
                     )
                 })?;
                 let cargo = CargoWorkspace::new(meta);
@@ -226,7 +219,6 @@ impl ProjectWorkspace {
                     rustc,
                     rustc_cfg,
                     cfg_overrides,
-                    toolchain,
                 }
             }
         };
@@ -279,8 +271,8 @@ impl ProjectWorkspace {
         progress: &dyn Fn(String),
     ) -> Result<WorkspaceBuildScripts> {
         match self {
-            ProjectWorkspace::Cargo { cargo, toolchain, .. } => {
-                WorkspaceBuildScripts::run(config, cargo, progress, toolchain).with_context(|| {
+            ProjectWorkspace::Cargo { cargo, .. } => {
+                WorkspaceBuildScripts::run(config, cargo, progress).with_context(|| {
                     format!("Failed to run build scripts for {}", &cargo.workspace_root().display())
                 })
             }
@@ -328,7 +320,6 @@ impl ProjectWorkspace {
                 rustc_cfg: _,
                 cfg_overrides: _,
                 build_scripts,
-                toolchain: _,
             } => {
                 cargo
                     .packages()
@@ -434,7 +425,6 @@ impl ProjectWorkspace {
                 rustc_cfg,
                 cfg_overrides,
                 build_scripts,
-                toolchain: _,
             } => cargo_to_crate_graph(
                 rustc_cfg.clone(),
                 cfg_overrides,
diff --git a/crates/rust-analyzer/src/reload.rs b/crates/rust-analyzer/src/reload.rs
index ceb2a6d703..49ccad71a1 100644
--- a/crates/rust-analyzer/src/reload.rs
+++ b/crates/rust-analyzer/src/reload.rs
@@ -219,7 +219,6 @@ impl GlobalState {
                     cfg_overrides,
 
                     build_scripts: _,
-                    toolchain: _,
                 } => Some((cargo, sysroot, rustc, rustc_cfg, cfg_overrides)),
                 _ => None,
             };


Test patch:
diff --git a/crates/hir-def/src/macro_expansion_tests/mbe.rs b/crates/hir-def/src/macro_expansion_tests/mbe.rs
index 457e43925c..30d39d52f3 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe.rs
@@ -885,7 +885,7 @@ macro_rules! m {
     ($t:ty) => ( fn bar() -> $ t {} )
 }
 
-fn bar() -> &'a Baz<u8> {}
+fn bar() -> & 'a Baz<u8> {}
 
 fn bar() -> extern "Rust"fn() -> Ret {}
 "#]],
@@ -1578,7 +1578,7 @@ macro_rules !register_methods {
             ($$($val: expr), *) = > {
                 struct Foo;
                 impl Foo {
-                    $(fn $method()-> &'static[u32] {
+                    $(fn $method()-> & 'static[u32] {
                         &[$$($$val), *]
                     }
                     )*
@@ -1591,10 +1591,10 @@ macro_rules !implement_methods {
     ($($val: expr), *) = > {
         struct Foo;
         impl Foo {
-            fn alpha()-> &'static[u32] {
+            fn alpha()-> & 'static[u32] {
                 &[$($val), *]
             }
-            fn beta()-> &'static[u32] {
+            fn beta()-> & 'static[u32] {
                 &[$($val), *]
             }
         }
@@ -1602,10 +1602,10 @@ macro_rules !implement_methods {
 }
 struct Foo;
 impl Foo {
-    fn alpha() -> &'static[u32] {
+    fn alpha() -> & 'static[u32] {
         &[1, 2, 3]
     }
-    fn beta() -> &'static[u32] {
+    fn beta() -> & 'static[u32] {
         &[1, 2, 3]
     }
 }
diff --git a/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs b/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs
index d2505e7caf..2dff4adf2e 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe/regression.rs
@@ -166,7 +166,7 @@ macro_rules! int_base {
     }
 }
 #[stable(feature = "rust1", since = "1.0.0")] impl fmt::Binary for isize {
-    fn fmt(&self , f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    fn fmt(&self , f: &mut fmt::Formatter< '_>) -> fmt::Result {
         Binary.fmt_int(*self as usize, f)
     }
 }
@@ -724,7 +724,7 @@ macro_rules! delegate_impl {
         }
     }
 }
-impl <> Data for &'amut G where G: Data {}
+impl <> Data for & 'amut G where G: Data {}
 "##]],
     );
 }
diff --git a/crates/hir-def/src/macro_expansion_tests/mbe/tt_conversion.rs b/crates/hir-def/src/macro_expansion_tests/mbe/tt_conversion.rs
index b8d2ca687c..0710b1ac3d 100644
--- a/crates/hir-def/src/macro_expansion_tests/mbe/tt_conversion.rs
+++ b/crates/hir-def/src/macro_expansion_tests/mbe/tt_conversion.rs
@@ -78,7 +78,7 @@ m!(static bar: &'static str = "hello";);
 macro_rules! m {
     ($($t:tt)*) => { $($t)*}
 }
-static bar: &'static str = "hello";
+static bar: & 'static str = "hello";
 "#]],
     );
 }
diff --git a/crates/hir-def/src/macro_expansion_tests/proc_macros.rs b/crates/hir-def/src/macro_expansion_tests/proc_macros.rs
index 029821e5e8..72c44a0fbc 100644
--- a/crates/hir-def/src/macro_expansion_tests/proc_macros.rs
+++ b/crates/hir-def/src/macro_expansion_tests/proc_macros.rs
@@ -87,7 +87,7 @@ fn foo() { bar.; blub }
 fn foo() { bar.; blub }
 
 fn foo() {
-    bar.;
+    bar. ;
     blub
 }"##]],
     );
diff --git a/crates/hir-ty/src/tests/patterns.rs b/crates/hir-ty/src/tests/patterns.rs
index 94efe7bc11..399553356b 100644
--- a/crates/hir-ty/src/tests/patterns.rs
+++ b/crates/hir-ty/src/tests/patterns.rs
@@ -315,51 +315,6 @@ fn infer_pattern_match_string_literal() {
     );
 }
 
-#[test]
-fn infer_pattern_match_byte_string_literal() {
-    check_infer_with_mismatches(
-        r#"
-        //- minicore: index
-        struct S;
-        impl<T, const N: usize> core::ops::Index<S> for [T; N] {
-            type Output = [u8];
-            fn index(&self, index: core::ops::RangeFull) -> &Self::Output {
-                loop {}
-            }
-        }
-        fn test(v: [u8; 3]) {
-            if let b"foo" = &v[S] {}
-            if let b"foo" = &v {}
-        }
-        "#,
-        expect![[r#"
-            105..109 'self': &[T; N]
-            111..116 'index': {unknown}
-            157..180 '{     ...     }': &[u8]
-            167..174 'loop {}': !
-            172..174 '{}': ()
-            191..192 'v': [u8; 3]
-            203..261 '{     ...v {} }': ()
-            209..233 'if let...[S] {}': ()
-            212..230 'let b"... &v[S]': bool
-            216..222 'b"foo"': &[u8]
-            216..222 'b"foo"': &[u8]
-            225..230 '&v[S]': &[u8]
-            226..227 'v': [u8; 3]
-            226..230 'v[S]': [u8]
-            228..229 'S': S
-            231..233 '{}': ()
-            238..259 'if let... &v {}': ()
-            241..256 'let b"foo" = &v': bool
-            245..251 'b"foo"': &[u8; 3]
-            245..251 'b"foo"': &[u8; 3]
-            254..256 '&v': &[u8; 3]
-            255..256 'v': [u8; 3]
-            257..259 '{}': ()
-        "#]],
-    );
-}
-
 #[test]
 fn infer_pattern_match_or() {
     check_infer_with_mismatches(
diff --git a/crates/ide-completion/src/tests/record.rs b/crates/ide-completion/src/tests/record.rs
index 328faaa060..f6accc68e5 100644
--- a/crates/ide-completion/src/tests/record.rs
+++ b/crates/ide-completion/src/tests/record.rs
@@ -103,9 +103,8 @@ fn foo(f: Struct) {
 }
 
 #[test]
-fn in_functional_update() {
-    cov_mark::check!(functional_update);
-
+fn functional_update() {
+    // FIXME: This should filter out all completions that do not have the type `Foo`
     check(
         r#"
 //- minicore:default
@@ -117,21 +116,13 @@ impl Default for Foo {
 fn main() {
     let thing = 1;
     let foo = Foo { foo1: 0, foo2: 0 };
-    let foo2 = Foo { thing, ..$0 }
+    let foo2 = Foo { thing, $0 }
 }
 "#,
         expect![[r#"
             fd ..Default::default()
-            fn main()               fn()
-            lc foo                  Foo
-            lc thing                i32
-            md core
-            st Foo
-            st Foo {…}              Foo { foo1: u32, foo2: u32 }
-            tt Default
-            bt u32
-            kw crate::
-            kw self::
+            fd foo1                 u32
+            fd foo2                 u32
         "#]],
     );
     check(
@@ -145,19 +136,14 @@ impl Default for Foo {
 fn main() {
     let thing = 1;
     let foo = Foo { foo1: 0, foo2: 0 };
-    let foo2 = Foo { thing, ..Default::$0 }
+    let foo2 = Foo { thing, .$0 }
 }
 "#,
         expect![[r#"
-            fn default() (as Default) fn() -> Self
+            fd ..Default::default()
+            sn ..
         "#]],
     );
-}
-
-#[test]
-fn functional_update_no_dot() {
-    cov_mark::check!(functional_update_field);
-    // FIXME: This should filter out all completions that do not have the type `Foo`
     check(
         r#"
 //- minicore:default
@@ -169,20 +155,23 @@ impl Default for Foo {
 fn main() {
     let thing = 1;
     let foo = Foo { foo1: 0, foo2: 0 };
-    let foo2 = Foo { thing, $0 }
+    let foo2 = Foo { thing, ..$0 }
 }
 "#,
         expect![[r#"
             fd ..Default::default()
-            fd foo1                 u32
-            fd foo2                 u32
+            fn main()               fn()
+            lc foo                  Foo
+            lc thing                i32
+            md core
+            st Foo
+            st Foo {…}              Foo { foo1: u32, foo2: u32 }
+            tt Default
+            bt u32
+            kw crate::
+            kw self::
         "#]],
     );
-}
-
-#[test]
-fn functional_update_one_dot() {
-    cov_mark::check!(functional_update_one_dot);
     check(
         r#"
 //- minicore:default
@@ -194,12 +183,11 @@ impl Default for Foo {
 fn main() {
     let thing = 1;
     let foo = Foo { foo1: 0, foo2: 0 };
-    let foo2 = Foo { thing, .$0 }
+    let foo2 = Foo { thing, ..Default::$0 }
 }
 "#,
         expect![[r#"
-            fd ..Default::default()
-            sn ..
+            fn default() (as Default) fn() -> Self
         "#]],
     );
 }
diff --git a/crates/parser/test_data/parser/inline/err/0014_record_literal_missing_ellipsis_recovery.rast b/crates/parser/test_data/parser/inline/err/0014_record_literal_missing_ellipsis_recovery.rast
deleted file mode 100644
index 0c5b618e6f..0000000000
--- a/crates/parser/test_data/parser/inline/err/0014_record_literal_missing_ellipsis_recovery.rast
+++ /dev/null
@@ -1,43 +0,0 @@
-SOURCE_FILE
-  FN
-    FN_KW "fn"
-    WHITESPACE " "
-    NAME
-      IDENT "main"
-    PARAM_LIST
-      L_PAREN "("
-      R_PAREN ")"
-    WHITESPACE " "
-    BLOCK_EXPR
-      STMT_LIST
-        L_CURLY "{"
-        WHITESPACE "\n    "
-        RECORD_EXPR
-          PATH
-            PATH_SEGMENT
-              NAME_REF
-                IDENT "S"
-          WHITESPACE " "
-          RECORD_EXPR_FIELD_LIST
-            L_CURLY "{"
-            WHITESPACE " "
-            CALL_EXPR
-              PATH_EXPR
-                PATH
-                  PATH
-                    PATH_SEGMENT
-                      NAME_REF
-                        IDENT "S"
-                  COLON2 "::"
-                  PATH_SEGMENT
-                    NAME_REF
-                      IDENT "default"
-              ARG_LIST
-                L_PAREN "("
-                R_PAREN ")"
-            WHITESPACE " "
-            R_CURLY "}"
-        WHITESPACE "\n"
-        R_CURLY "}"
-  WHITESPACE "\n"
-error 19: expected DOT2
diff --git a/crates/parser/test_data/parser/inline/err/0014_record_literal_missing_ellipsis_recovery.rs b/crates/parser/test_data/parser/inline/err/0014_record_literal_missing_ellipsis_recovery.rs
deleted file mode 100644
index 1b594e8ab9..0000000000
--- a/crates/parser/test_data/parser/inline/err/0014_record_literal_missing_ellipsis_recovery.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-fn main() {
-    S { S::default() }
-}
diff --git a/crates/parser/test_data/parser/inline/ok/0061_record_lit.rast b/crates/parser/test_data/parser/inline/ok/0061_record_lit.rast
index 00948c322f..9997d0ae34 100644
--- a/crates/parser/test_data/parser/inline/ok/0061_record_lit.rast
+++ b/crates/parser/test_data/parser/inline/ok/0061_record_lit.rast
@@ -24,26 +24,6 @@ SOURCE_FILE
               R_CURLY "}"
           SEMICOLON ";"
         WHITESPACE "\n    "
-        EXPR_STMT
-          RECORD_EXPR
-            PATH
-              PATH_SEGMENT
-                NAME_REF
-                  IDENT "S"
-            WHITESPACE " "
-            RECORD_EXPR_FIELD_LIST
-              L_CURLY "{"
-              WHITESPACE " "
-              RECORD_EXPR_FIELD
-                PATH_EXPR
-                  PATH
-                    PATH_SEGMENT
-                      NAME_REF
-                        IDENT "x"
-              WHITESPACE " "
-              R_CURLY "}"
-          SEMICOLON ";"
-        WHITESPACE "\n    "
         EXPR_STMT
           RECORD_EXPR
             PATH
@@ -120,35 +100,6 @@ SOURCE_FILE
               R_CURLY "}"
           SEMICOLON ";"
         WHITESPACE "\n    "
-        EXPR_STMT
-          RECORD_EXPR
-            PATH
-              PATH_SEGMENT
-                NAME_REF
-                  IDENT "S"
-            WHITESPACE " "
-            RECORD_EXPR_FIELD_LIST
-              L_CURLY "{"
-              WHITESPACE " "
-              RECORD_EXPR_FIELD
-                NAME_REF
-                  IDENT "x"
-                COLON ":"
-                WHITESPACE " "
-                CALL_EXPR
-                  PATH_EXPR
-                    PATH
-                      PATH_SEGMENT
-                        COLON2 "::"
-                        NAME_REF
-                          IDENT "default"
-                  ARG_LIST
-                    L_PAREN "("
-                    R_PAREN ")"
-              WHITESPACE " "
-              R_CURLY "}"
-          SEMICOLON ";"
-        WHITESPACE "\n    "
         EXPR_STMT
           RECORD_EXPR
             PATH
diff --git a/crates/parser/test_data/parser/inline/ok/0061_record_lit.rs b/crates/parser/test_data/parser/inline/ok/0061_record_lit.rs
index 86411fbb7d..6285e55497 100644
--- a/crates/parser/test_data/parser/inline/ok/0061_record_lit.rs
+++ b/crates/parser/test_data/parser/inline/ok/0061_record_lit.rs
@@ -1,8 +1,6 @@
 fn foo() {
     S {};
-    S { x };
     S { x, y: 32, };
     S { x, y: 32, ..Default::default() };
-    S { x: ::default() };
     TupleStruct { 0: 1 };
 }
diff --git a/crates/proc-macro-srv/src/tests/mod.rs b/crates/proc-macro-srv/src/tests/mod.rs
index 6339d56d01..07222907f0 100644
--- a/crates/proc-macro-srv/src/tests/mod.rs
+++ b/crates/proc-macro-srv/src/tests/mod.rs
@@ -19,7 +19,7 @@ fn test_derive_error() {
         expect![[r##"
             SUBTREE $
               IDENT   compile_error 4294967295
-              PUNCH   ! [joint] 4294967295
+              PUNCH   ! [alone] 4294967295
               SUBTREE () 4294967295
                 LITERAL "#[derive(DeriveError)] struct S ;" 4294967295
               PUNCH   ; [alone] 4294967295"##]],
@@ -109,7 +109,7 @@ fn test_fn_like_macro_clone_literals() {
               PUNCH   , [alone] 4294967295
               LITERAL 2_u32 4294967295
               PUNCH   , [alone] 4294967295
-              PUNCH   - [joint] 4294967295
+              PUNCH   - [alone] 4294967295
               LITERAL 4i64 4294967295
               PUNCH   , [alone] 4294967295
               LITERAL 3.14f32 4294967295
@@ -130,7 +130,7 @@ fn test_attr_macro() {
         expect![[r##"
             SUBTREE $
               IDENT   compile_error 4294967295
-              PUNCH   ! [joint] 4294967295
+              PUNCH   ! [alone] 4294967295
               SUBTREE () 4294967295
                 LITERAL "#[attr_error(some arguments)] mod m {}" 4294967295
               PUNCH   ; [alone] 4294967295"##]],
diff --git a/crates/project-model/src/tests.rs b/crates/project-model/src/tests.rs
index 8d0fa757c2..e304a59c01 100644
--- a/crates/project-model/src/tests.rs
+++ b/crates/project-model/src/tests.rs
@@ -28,7 +28,6 @@ fn load_cargo_with_overrides(file: &str, cfg_overrides: CfgOverrides) -> CrateGr
         rustc: None,
         rustc_cfg: Vec::new(),
         cfg_overrides,
-        toolchain: None,
     };
     to_crate_graph(project_workspace)
 }