Repository: rust-lang/rust-analyzer
Pull request #16771 (2024-03-06 14:57:31)

internal: Don't desugar self param into a pattern
Small experiment to see if this simplifies things

Veykril: This does cause some extra code duplication but it reflects better when it comes to source mapping back, as now strictly pattern syntax is tied to lowered patterns, instead of a nasty either. Imo it feels nicer this way even if it costs us a bit of extra code.
bors: :umbrella: The latest upstream changes (presumably #16779) made this pull request unmergeable. Please [resolve the merge conflicts](https://rustc-dev-guide.rust-lang.org/git.html#rebasing-and-conflicts).

Patch:
diff --git a/crates/hir-def/src/body.rs b/crates/hir-def/src/body.rs
index 37d37fd331..c9f1add275 100644
--- a/crates/hir-def/src/body.rs
+++ b/crates/hir-def/src/body.rs
@@ -10,7 +10,6 @@ use std::ops::Index;
 
 use base_db::CrateId;
 use cfg::{CfgExpr, CfgOptions};
-use either::Either;
 use hir_expand::{name::Name, HirFileId, InFile};
 use la_arena::{Arena, ArenaMap};
 use rustc_hash::FxHashMap;
@@ -45,7 +44,8 @@ pub struct Body {
     ///
     /// If this `Body` is for the body of a constant, this will just be
     /// empty.
-    pub params: Vec<PatId>,
+    pub params: Box<[PatId]>,
+    pub self_param: Option<BindingId>,
     /// The `ExprId` of the actual body expression.
     pub body_expr: ExprId,
     /// Block expressions in this body that may contain inner items.
@@ -55,7 +55,7 @@ pub struct Body {
 pub type ExprPtr = AstPtr<ast::Expr>;
 pub type ExprSource = InFile<ExprPtr>;
 
-pub type PatPtr = AstPtr<Either<ast::Pat, ast::SelfParam>>;
+pub type PatPtr = AstPtr<ast::Pat>;
 pub type PatSource = InFile<PatPtr>;
 
 pub type LabelPtr = AstPtr<ast::Label>;
@@ -63,6 +63,7 @@ pub type LabelSource = InFile<LabelPtr>;
 
 pub type FieldPtr = AstPtr<ast::RecordExprField>;
 pub type FieldSource = InFile<FieldPtr>;
+
 pub type PatFieldPtr = AstPtr<ast::RecordPatField>;
 pub type PatFieldSource = InFile<PatFieldPtr>;
 
@@ -88,6 +89,8 @@ pub struct BodySourceMap {
     label_map: FxHashMap<LabelSource, LabelId>,
     label_map_back: ArenaMap<LabelId, LabelSource>,
 
+    self_param: Option<InFile<AstPtr<ast::SelfParam>>>,
+
     /// We don't create explicit nodes for record fields (`S { record_field: 92 }`).
     /// Instead, we use id of expression (`92`) to identify the field.
     field_map_back: FxHashMap<ExprId, FieldSource>,
@@ -215,10 +218,11 @@ impl Body {
     fn shrink_to_fit(&mut self) {
         let Self {
             body_expr: _,
+            params: _,
+            self_param: _,
             block_scopes,
             exprs,
             labels,
-            params,
             pats,
             bindings,
             binding_owners,
@@ -226,7 +230,6 @@ impl Body {
         block_scopes.shrink_to_fit();
         exprs.shrink_to_fit();
         labels.shrink_to_fit();
-        params.shrink_to_fit();
         pats.shrink_to_fit();
         bindings.shrink_to_fit();
         binding_owners.shrink_to_fit();
@@ -297,6 +300,7 @@ impl Default for Body {
             params: Default::default(),
             block_scopes: Default::default(),
             binding_owners: Default::default(),
+            self_param: Default::default(),
         }
     }
 }
@@ -354,14 +358,12 @@ impl BodySourceMap {
         self.pat_map_back.get(pat).cloned().ok_or(SyntheticSyntax)
     }
 
-    pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
-        let src = node.map(|it| AstPtr::new(it).wrap_left());
-        self.pat_map.get(&src).cloned()
+    pub fn self_param_syntax(&self) -> Option<InFile<AstPtr<ast::SelfParam>>> {
+        self.self_param
     }
 
-    pub fn node_self_param(&self, node: InFile<&ast::SelfParam>) -> Option<PatId> {
-        let src = node.map(|it| AstPtr::new(it).wrap_right());
-        self.pat_map.get(&src).cloned()
+    pub fn node_pat(&self, node: InFile<&ast::Pat>) -> Option<PatId> {
+        self.pat_map.get(&node.map(AstPtr::new)).cloned()
     }
 
     pub fn label_syntax(&self, label: LabelId) -> LabelSource {
@@ -401,6 +403,7 @@ impl BodySourceMap {
 
     fn shrink_to_fit(&mut self) {
         let Self {
+            self_param: _,
             expr_map,
             expr_map_back,
             pat_map,
diff --git a/crates/hir-def/src/body/lower.rs b/crates/hir-def/src/body/lower.rs
index 6669127789..340e95dbc2 100644
--- a/crates/hir-def/src/body/lower.rs
+++ b/crates/hir-def/src/body/lower.rs
@@ -4,7 +4,6 @@
 use std::mem;
 
 use base_db::CrateId;
-use either::Either;
 use hir_expand::{
     name::{name, AsName, Name},
     ExpandError, InFile,
@@ -29,7 +28,6 @@ use crate::{
     db::DefDatabase,
     expander::Expander,
     hir::{
-        dummy_expr_id,
         format_args::{
             self, FormatAlignment, FormatArgs, FormatArgsPiece, FormatArgument, FormatArgumentKind,
             FormatArgumentsCollector, FormatCount, FormatDebugHex, FormatOptions,
@@ -66,16 +64,7 @@ pub(super) fn lower(
         def_map: expander.module.def_map(db),
         source_map: BodySourceMap::default(),
         ast_id_map: db.ast_id_map(expander.current_file_id()),
-        body: Body {
-            exprs: Default::default(),
-            pats: Default::default(),
-            bindings: Default::default(),
-            binding_owners: Default::default(),
-            labels: Default::default(),
-            params: Vec::new(),
-            body_expr: dummy_expr_id(),
-            block_scopes: Vec::new(),
-        },
+        body: Body::default(),
         expander,
         current_try_block_label: None,
         is_lowering_assignee_expr: false,
@@ -191,35 +180,35 @@ impl ExprCollector<'_> {
         is_async_fn: bool,
     ) -> (Body, BodySourceMap) {
         if let Some((param_list, mut attr_enabled)) = param_list {
+            let mut params = vec![];
             if let Some(self_param) =
                 param_list.self_param().filter(|_| attr_enabled.next().unwrap_or(false))
             {
                 let is_mutable =
                     self_param.mut_token().is_some() && self_param.amp_token().is_none();
-                let ptr = AstPtr::new(&Either::Right(self_param));
                 let binding_id: la_arena::Idx<Binding> =
                     self.alloc_binding(name![self], BindingAnnotation::new(is_mutable, false));
-                let param_pat = self.alloc_pat(Pat::Bind { id: binding_id, subpat: None }, ptr);
-                self.add_definition_to_binding(binding_id, param_pat);
-                self.body.params.push(param_pat);
+                self.body.self_param = Some(binding_id);
+                self.source_map.self_param = Some(self.expander.in_file(AstPtr::new(&self_param)));
             }
 
             for (param, _) in param_list.params().zip(attr_enabled).filter(|(_, enabled)| *enabled)
             {
                 let param_pat = self.collect_pat_top(param.pat());
-                self.body.params.push(param_pat);
+                params.push(param_pat);
             }
+            self.body.params = params.into_boxed_slice();
         };
         self.body.body_expr = self.with_label_rib(RibKind::Closure, |this| {
             if is_async_fn {
                 match body {
                     Some(e) => {
+                        let syntax_ptr = AstPtr::new(&e);
                         let expr = this.collect_expr(e);
-                        this.alloc_expr_desugared(Expr::Async {
-                            id: None,
-                            statements: Box::new([]),
-                            tail: Some(expr),
-                        })
+                        this.alloc_expr_desugared_with_ptr(
+                            Expr::Async { id: None, statements: Box::new([]), tail: Some(expr) },
+                            syntax_ptr,
+                        )
                     }
                     None => this.missing_expr(),
                 }
@@ -405,7 +394,7 @@ impl ExprCollector<'_> {
             }
             ast::Expr::ParenExpr(e) => {
                 let inner = self.collect_expr_opt(e.expr());
-                // make the paren expr point to the inner expression as well
+                // make the paren expr point to the inner expression as well for IDE resolution
                 let src = self.expander.in_file(syntax_ptr);
                 self.source_map.expr_map.insert(src, inner);
                 inner
@@ -707,6 +696,7 @@ impl ExprCollector<'_> {
             .alloc_label_desugared(Label { name: Name::generate_new_name(self.body.labels.len()) });
         let old_label = self.current_try_block_label.replace(label);
 
+        let ptr = AstPtr::new(&e).upcast();
         let (btail, expr_id) = self.with_labeled_rib(label, |this| {
             let mut btail = None;
             let block = this.collect_block_(e, |id, statements, tail| {
@@ -716,23 +706,21 @@ impl ExprCollector<'_> {
             (btail, block)
         });
 
-        let callee = self.alloc_expr_desugared(Expr::Path(try_from_output));
+        let callee = self.alloc_expr_desugared_with_ptr(Expr::Path(try_from_output), ptr);
         let next_tail = match btail {
-            Some(tail) => self.alloc_expr_desugared(Expr::Call {
-                callee,
-                args: Box::new([tail]),
-                is_assignee_expr: false,
-            }),
+            Some(tail) => self.alloc_expr_desugared_with_ptr(
+                Expr::Call { callee, args: Box::new([tail]), is_assignee_expr: false },
+                ptr,
+            ),
             None => {
-                let unit = self.alloc_expr_desugared(Expr::Tuple {
-                    exprs: Box::new([]),
-                    is_assignee_expr: false,
-                });
-                self.alloc_expr_desugared(Expr::Call {
-                    callee,
-                    args: Box::new([unit]),
-                    is_assignee_expr: false,
-                })
+                let unit = self.alloc_expr_desugared_with_ptr(
+                    Expr::Tuple { exprs: Box::new([]), is_assignee_expr: false },
+                    ptr,
+                );
+                self.alloc_expr_desugared_with_ptr(
+                    Expr::Call { callee, args: Box::new([unit]), is_assignee_expr: false },
+                    ptr,
+                )
             }
         };
         let Expr::Block { tail, .. } = &mut self.body.exprs[expr_id] else {
@@ -1067,16 +1055,12 @@ impl ExprCollector<'_> {
                 None => None,
             },
         );
-        match expansion {
-            Some(tail) => {
-                // Make the macro-call point to its expanded expression so we can query
-                // semantics on syntax pointers to the macro
-                let src = self.expander.in_file(syntax_ptr);
-                self.source_map.expr_map.insert(src, tail);
-                Some(tail)
-            }
-            None => None,
-        }
+        expansion.inspect(|&tail| {
+            // Make the macro-call point to its expanded expression so we can query
+            // semantics on syntax pointers to the macro
+            let src = self.expander.in_file(syntax_ptr);
+            self.source_map.expr_map.insert(src, tail);
+        })
     }
 
     fn collect_stmt(&mut self, statements: &mut Vec<Statement>, s: ast::Stmt) {
@@ -1261,7 +1245,7 @@ impl ExprCollector<'_> {
                     (Some(id), Pat::Bind { id, subpat })
                 };
 
-                let ptr = AstPtr::new(&Either::Left(pat));
+                let ptr = AstPtr::new(&pat);
                 let pat = self.alloc_pat(pattern, ptr);
                 if let Some(binding_id) = binding {
                     self.add_definition_to_binding(binding_id, pat);
@@ -1359,9 +1343,10 @@ impl ExprCollector<'_> {
                     suffix: suffix.into_iter().map(|p| self.collect_pat(p, binding_list)).collect(),
                 }
             }
-            #[rustfmt::skip] // https://github.com/rust-lang/rustfmt/issues/5676
             ast::Pat::LiteralPat(lit) => 'b: {
-                let Some((hir_lit, ast_lit)) = pat_literal_to_hir(lit) else { break 'b Pat::Missing };
+                let Some((hir_lit, ast_lit)) = pat_literal_to_hir(lit) else {
+                    break 'b Pat::Missing;
+                };
                 let expr = Expr::Literal(hir_lit);
                 let expr_ptr = AstPtr::new(&ast::Expr::Literal(ast_lit));
                 let expr_id = self.alloc_expr(expr, expr_ptr);
@@ -1397,7 +1382,7 @@ impl ExprCollector<'_> {
             ast::Pat::MacroPat(mac) => match mac.macro_call() {
                 Some(call) => {
                     let macro_ptr = AstPtr::new(&call);
-                    let src = self.expander.in_file(AstPtr::new(&Either::Left(pat)));
+                    let src = self.expander.in_file(AstPtr::new(&pat));
                     let pat =
                         self.collect_macro_call(call, macro_ptr, true, |this, expanded_pat| {
                             this.collect_pat_opt(expanded_pat, binding_list)
@@ -1426,7 +1411,7 @@ impl ExprCollector<'_> {
                 Pat::Range { start, end }
             }
         };
-        let ptr = AstPtr::new(&Either::Left(pat));
+        let ptr = AstPtr::new(&pat);
         self.alloc_pat(pattern, ptr)
     }
 
@@ -1987,10 +1972,19 @@ impl ExprCollector<'_> {
         self.source_map.expr_map.insert(src, id);
         id
     }
-    // FIXME: desugared exprs don't have ptr, that's wrong and should be fixed somehow.
+    // FIXME: desugared exprs don't have ptr, that's wrong and should be fixed.
+    // Migrate to alloc_expr_desugared_with_ptr and then rename back
     fn alloc_expr_desugared(&mut self, expr: Expr) -> ExprId {
         self.body.exprs.alloc(expr)
     }
+    fn alloc_expr_desugared_with_ptr(&mut self, expr: Expr, ptr: ExprPtr) -> ExprId {
+        let src = self.expander.in_file(ptr);
+        let id = self.body.exprs.alloc(expr);
+        self.source_map.expr_map_back.insert(id, src);
+        // We intentionally don't fill this as it could overwrite a non-desugared entry
+        // self.source_map.expr_map.insert(src, id);
+        id
+    }
     fn missing_expr(&mut self) -> ExprId {
         self.alloc_expr_desugared(Expr::Missing)
     }
diff --git a/crates/hir-def/src/body/pretty.rs b/crates/hir-def/src/body/pretty.rs
index b2aab55a6a..cbb5ca887f 100644
--- a/crates/hir-def/src/body/pretty.rs
+++ b/crates/hir-def/src/body/pretty.rs
@@ -48,7 +48,16 @@ pub(super) fn print_body_hir(db: &dyn DefDatabase, body: &Body, owner: DefWithBo
     let mut p = Printer { db, body, buf: header, indent_level: 0, needs_indent: false };
     if let DefWithBodyId::FunctionId(it) = owner {
         p.buf.push('(');
-        body.params.iter().zip(db.function_data(it).params.iter()).for_each(|(&param, ty)| {
+        let params = &db.function_data(it).params;
+        let mut params = params.iter();
+        if let Some(self_param) = body.self_param {
+            p.print_binding(self_param);
+            p.buf.push(':');
+            if let Some(ty) = params.next() {
+                p.print_type_ref(ty);
+            }
+        }
+        body.params.iter().zip(params).for_each(|(&param, ty)| {
             p.print_pat(param);
             p.buf.push(':');
             p.print_type_ref(ty);
diff --git a/crates/hir-def/src/body/scope.rs b/crates/hir-def/src/body/scope.rs
index 69b82ae871..0020e4eac3 100644
--- a/crates/hir-def/src/body/scope.rs
+++ b/crates/hir-def/src/body/scope.rs
@@ -96,6 +96,9 @@ impl ExprScopes {
             scope_by_expr: ArenaMap::with_capacity(body.exprs.len()),
         };
         let mut root = scopes.root_scope();
+        if let Some(self_param) = body.self_param {
+            scopes.add_bindings(body, root, self_param);
+        }
         scopes.add_params_bindings(body, root, &body.params);
         compute_expr_scopes(body.body_expr, body, &mut scopes, &mut root);
         scopes
diff --git a/crates/hir-ty/src/infer.rs b/crates/hir-ty/src/infer.rs
index 9cea414e1a..34ba17f145 100644
--- a/crates/hir-ty/src/infer.rs
+++ b/crates/hir-ty/src/infer.rs
@@ -22,7 +22,7 @@ mod pat;
 mod path;
 pub(crate) mod unify;
 
-use std::{convert::identity, ops::Index};
+use std::{convert::identity, iter, ops::Index};
 
 use chalk_ir::{
     cast::Cast, fold::TypeFoldable, interner::HasInterner, DebruijnIndex, Mutability, Safety,
@@ -777,7 +777,15 @@ impl<'a> InferenceContext<'a> {
 
             param_tys.push(va_list_ty)
         }
-        for (ty, pat) in param_tys.into_iter().zip(self.body.params.iter()) {
+        let mut param_tys = param_tys.into_iter().chain(iter::repeat(self.table.new_type_var()));
+        if let Some(self_param) = self.body.self_param {
+            if let Some(ty) = param_tys.next() {
+                let ty = self.insert_type_vars(ty);
+                let ty = self.normalize_associated_types_in(ty);
+                self.write_binding_ty(self_param, ty);
+            }
+        }
+        for (ty, pat) in param_tys.zip(&*self.body.params) {
             let ty = self.insert_type_vars(ty);
             let ty = self.normalize_associated_types_in(ty);
 
diff --git a/crates/hir-ty/src/layout.rs b/crates/hir-ty/src/layout.rs
index dea292711d..9655981cc9 100644
--- a/crates/hir-ty/src/layout.rs
+++ b/crates/hir-ty/src/layout.rs
@@ -371,8 +371,8 @@ pub fn layout_of_ty_query(
         TyKind::Never => cx.layout_of_never_type(),
         TyKind::Dyn(_) | TyKind::Foreign(_) => {
             let mut unit = layout_of_unit(&cx, dl)?;
-            match unit.abi {
-                Abi::Aggregate { ref mut sized } => *sized = false,
+            match &mut unit.abi {
+                Abi::Aggregate { sized } => *sized = false,
                 _ => return Err(LayoutError::Unknown),
             }
             unit
diff --git a/crates/hir-ty/src/mir.rs b/crates/hir-ty/src/mir.rs
index cfaef2a392..d513355037 100644
--- a/crates/hir-ty/src/mir.rs
+++ b/crates/hir-ty/src/mir.rs
@@ -1165,6 +1165,7 @@ impl MirBody {
 pub enum MirSpan {
     ExprId(ExprId),
     PatId(PatId),
+    SelfParam,
     Unknown,
 }
 
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 2428678d72..fd98141af6 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -376,6 +376,10 @@ impl MirEvalError {
                         Ok(s) => s.map(|it| it.syntax_node_ptr()),
                         Err(_) => continue,
                     },
+                    MirSpan::SelfParam => match source_map.self_param_syntax() {
+                        Some(s) => s.map(|it| it.syntax_node_ptr()),
+                        None => continue,
+                    },
                     MirSpan::Unknown => continue,
                 };
                 let file_id = span.file_id.original_file(db.upcast());
diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs
index d0f739e6ac..7e582c03ef 100644
--- a/crates/hir-ty/src/mir/lower.rs
+++ b/crates/hir-ty/src/mir/lower.rs
@@ -1810,9 +1810,20 @@ impl<'ctx> MirLowerCtx<'ctx> {
     fn lower_params_and_bindings(
         &mut self,
         params: impl Iterator<Item = (PatId, Ty)> + Clone,
+        self_binding: Option<(BindingId, Ty)>,
         pick_binding: impl Fn(BindingId) -> bool,
     ) -> Result<BasicBlockId> {
         let base_param_count = self.result.param_locals.len();
+        let self_binding = match self_binding {
+            Some((self_binding, ty)) => {
+                let local_id = self.result.locals.alloc(Local { ty });
+                self.drop_scopes.last_mut().unwrap().locals.push(local_id);
+                self.result.binding_locals.insert(self_binding, local_id);
+                self.result.param_locals.push(local_id);
+                Some(self_binding)
+            }
+            None => None,
+        };
         self.result.param_locals.extend(params.clone().map(|(it, ty)| {
             let local_id = self.result.locals.alloc(Local { ty });
             self.drop_scopes.last_mut().unwrap().locals.push(local_id);
@@ -1838,9 +1849,23 @@ impl<'ctx> MirLowerCtx<'ctx> {
             }
         }
         let mut current = self.result.start_block;
-        for ((param, _), local) in
-            params.zip(self.result.param_locals.clone().into_iter().skip(base_param_count))
-        {
+        if let Some(self_binding) = self_binding {
+            let local = self.result.param_locals.clone()[base_param_count];
+            if local != self.binding_local(self_binding)? {
+                let r = self.match_self_param(self_binding, current, local)?;
+                if let Some(b) = r.1 {
+                    self.set_terminator(b, TerminatorKind::Unreachable, MirSpan::SelfParam);
+                }
+                current = r.0;
+            }
+        }
+        let local_params = self
+            .result
+            .param_locals
+            .clone()
+            .into_iter()
+            .skip(base_param_count + self_binding.is_some() as usize);
+        for ((param, _), local) in params.zip(local_params) {
             if let Pat::Bind { id, .. } = self.body[param] {
                 if local == self.binding_local(id)? {
                     continue;
@@ -2019,6 +2044,7 @@ pub fn mir_body_for_closure_query(
     };
     let current = ctx.lower_params_and_bindings(
         args.iter().zip(sig.params().iter()).map(|(it, y)| (*it, y.clone())),
+        None,
         |_| true,
     )?;
     if let Some(current) = ctx.lower_expr_to_place(*root, return_slot().into(), current)? {
@@ -2149,16 +2175,16 @@ pub fn lower_to_mir(
                 let substs = TyBuilder::placeholder_subst(db, fid);
                 let callable_sig =
                     db.callable_item_signature(fid.into()).substitute(Interner, &substs);
+                let mut params = callable_sig.params().iter();
+                let self_param = body.self_param.and_then(|id| Some((id, params.next()?.clone())));
                 break 'b ctx.lower_params_and_bindings(
-                    body.params
-                        .iter()
-                        .zip(callable_sig.params().iter())
-                        .map(|(it, y)| (*it, y.clone())),
+                    body.params.iter().zip(params).map(|(it, y)| (*it, y.clone())),
+                    self_param,
                     binding_picker,
                 )?;
             }
         }
-        ctx.lower_params_and_bindings([].into_iter(), binding_picker)?
+        ctx.lower_params_and_bindings([].into_iter(), None, binding_picker)?
     };
     if let Some(current) = ctx.lower_expr_to_place(root_expr, return_slot().into(), current)? {
         let current = ctx.pop_drop_scope_assert_finished(current, root_expr.into())?;
diff --git a/crates/hir-ty/src/mir/lower/pattern_matching.rs b/crates/hir-ty/src/mir/lower/pattern_matching.rs
index 90cbd13a6c..7596906794 100644
--- a/crates/hir-ty/src/mir/lower/pattern_matching.rs
+++ b/crates/hir-ty/src/mir/lower/pattern_matching.rs
@@ -11,7 +11,7 @@ use crate::{
             Substitution, SwitchTargets, TerminatorKind, TupleFieldId, TupleId, TyBuilder, TyKind,
             ValueNs, VariantData, VariantId,
         },
-        MutBorrowKind,
+        LocalId, MutBorrowKind,
     },
     BindingMode,
 };
@@ -82,6 +82,22 @@ impl MirLowerCtx<'_> {
         Ok((current, current_else))
     }
 
+    pub(super) fn match_self_param(
+        &mut self,
+        id: BindingId,
+        current: BasicBlockId,
+        local: LocalId,
+    ) -> Result<(BasicBlockId, Option<BasicBlockId>)> {
+        self.pattern_match_binding(
+            id,
+            BindingMode::Move,
+            local.into(),
+            MirSpan::SelfParam,
+            current,
+            None,
+        )
+    }
+
     fn pattern_match_inner(
         &mut self,
         mut current: BasicBlockId,
@@ -283,9 +299,9 @@ impl MirLowerCtx<'_> {
                     (current, current_else) =
                         self.pattern_match_inner(current, current_else, next_place, pat, mode)?;
                 }
-                if let Some(slice) = slice {
+                if let &Some(slice) = slice {
                     if mode == MatchingMode::Bind {
-                        if let Pat::Bind { id, subpat: _ } = self.body[*slice] {
+                        if let Pat::Bind { id, subpat: _ } = self.body[slice] {
                             let next_place = cond_place.project(
                                 ProjectionElem::Subslice {
                                     from: prefix.len() as u64,
@@ -293,11 +309,12 @@ impl MirLowerCtx<'_> {
                                 },
                                 &mut self.result.projection_store,
                             );
+                            let mode = self.infer.binding_modes[slice];
                             (current, current_else) = self.pattern_match_binding(
                                 id,
-                                *slice,
+                                mode,
                                 next_place,
-                                (*slice).into(),
+                                (slice).into(),
                                 current,
                                 current_else,
                             )?;
@@ -398,9 +415,10 @@ impl MirLowerCtx<'_> {
                         self.pattern_match_inner(current, current_else, cond_place, *subpat, mode)?
                 }
                 if mode == MatchingMode::Bind {
+                    let mode = self.infer.binding_modes[pattern];
                     self.pattern_match_binding(
                         *id,
-                        pattern,
+                        mode,
                         cond_place,
                         pattern.into(),
                         current,
@@ -437,14 +455,13 @@ impl MirLowerCtx<'_> {
     fn pattern_match_binding(
         &mut self,
         id: BindingId,
-        pat: PatId,
+        mode: BindingMode,
         cond_place: Place,
         span: MirSpan,
         current: BasicBlockId,
         current_else: Option<BasicBlockId>,
     ) -> Result<(BasicBlockId, Option<BasicBlockId>)> {
         let target_place = self.binding_local(id)?;
-        let mode = self.infer.binding_modes[pat];
         self.push_storage_live(id, current)?;
         self.push_assignment(
             current,
diff --git a/crates/hir/src/diagnostics.rs b/crates/hir/src/diagnostics.rs
index fa9fe4953e..4518422d27 100644
--- a/crates/hir/src/diagnostics.rs
+++ b/crates/hir/src/diagnostics.rs
@@ -204,7 +204,7 @@ pub struct NoSuchField {
 
 #[derive(Debug)]
 pub struct PrivateAssocItem {
-    pub expr_or_pat: InFile<AstPtr<Either<ast::Expr, Either<ast::Pat, ast::SelfParam>>>>,
+    pub expr_or_pat: InFile<AstPtr<Either<ast::Expr, ast::Pat>>>,
     pub item: AssocItem,
 }
 
@@ -240,7 +240,7 @@ pub struct UnresolvedMethodCall {
 
 #[derive(Debug)]
 pub struct UnresolvedAssocItem {
-    pub expr_or_pat: InFile<AstPtr<Either<ast::Expr, Either<ast::Pat, ast::SelfParam>>>>,
+    pub expr_or_pat: InFile<AstPtr<Either<ast::Expr, ast::Pat>>>,
 }
 
 #[derive(Debug)]
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 5eed7ecd5b..ea15535670 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -1725,6 +1725,10 @@ impl DefWithBody {
                             Ok(s) => s.map(|it| it.into()),
                             Err(_) => continue,
                         },
+                        mir::MirSpan::SelfParam => match source_map.self_param_syntax() {
+                            Some(s) => s.map(|it| it.into()),
+                            None => continue,
+                        },
                         mir::MirSpan::Unknown => continue,
                     };
                     acc.push(
@@ -1776,6 +1780,11 @@ impl DefWithBody {
                                         Ok(s) => s.map(|it| it.into()),
                                         Err(_) => continue,
                                     },
+                                    mir::MirSpan::SelfParam => match source_map.self_param_syntax()
+                                    {
+                                        Some(s) => s.map(|it| it.into()),
+                                        None => continue,
+                                    },
                                     mir::MirSpan::Unknown => continue,
                                 };
                                 acc.push(NeedMut { local, span }.into());
@@ -2127,8 +2136,11 @@ impl Param {
     pub fn as_local(&self, db: &dyn HirDatabase) -> Option<Local> {
         let parent = DefWithBodyId::FunctionId(self.func.into());
         let body = db.body(parent);
-        let pat_id = body.params[self.idx];
-        if let Pat::Bind { id, .. } = &body[pat_id] {
+        if let Some(self_param) = body.self_param.filter(|_| self.idx == 0) {
+            Some(Local { parent, binding_id: self_param })
+        } else if let Pat::Bind { id, .. } =
+            &body[body.params[self.idx - body.self_param.is_some() as usize]]
+        {
             Some(Local { parent, binding_id: *id })
         } else {
             None
@@ -2143,7 +2155,7 @@ impl Param {
         let InFile { file_id, value } = self.func.source(db)?;
         let params = value.param_list()?;
         if params.self_param().is_some() {
-            params.params().nth(self.idx.checked_sub(1)?)
+            params.params().nth(self.idx.checked_sub(params.self_param().is_some() as usize)?)
         } else {
             params.params().nth(self.idx)
         }
@@ -3134,35 +3146,59 @@ impl Local {
     /// All definitions for this local. Example: `let (a$0, _) | (_, a$0) = it;`
     pub fn sources(self, db: &dyn HirDatabase) -> Vec<LocalSource> {
         let (body, source_map) = db.body_with_source_map(self.parent);
-        self.sources_(db, &body, &source_map).collect()
+        match body.self_param.zip(source_map.self_param_syntax()) {
+            Some((param, source)) if param == self.binding_id => {
+                let root = source.file_syntax(db.upcast());
+                vec![LocalSource {
+                    local: self,
+                    source: source.map(|ast| Either::Right(ast.to_node(&root))),
+                }]
+            }
+            _ => body[self.binding_id]
+                .definitions
+                .iter()
+                .map(|&definition| {
+                    let src = source_map.pat_syntax(definition).unwrap(); // Hmm...
+                    let root = src.file_syntax(db.upcast());
+                    LocalSource {
+                        local: self,
+                        source: src.map(|ast| match ast.to_node(&root) {
+                            ast::Pat::IdentPat(it) => Either::Left(it),
+                            _ => unreachable!("local with non ident-pattern"),
+                        }),
+                    }
+                })
+                .collect(),
+        }
     }
 
     /// The leftmost definition for this local. Example: `let (a$0, _) | (_, a) = it;`
     pub fn primary_source(self, db: &dyn HirDatabase) -> LocalSource {
         let (body, source_map) = db.body_with_source_map(self.parent);
-        let src = self.sources_(db, &body, &source_map).next().unwrap();
-        src
-    }
-
-    fn sources_<'a>(
-        self,
-        db: &'a dyn HirDatabase,
-        body: &'a hir_def::body::Body,
-        source_map: &'a hir_def::body::BodySourceMap,
-    ) -> impl Iterator<Item = LocalSource> + 'a {
-        body[self.binding_id]
-            .definitions
-            .iter()
-            .map(|&definition| {
-                let src = source_map.pat_syntax(definition).unwrap(); // Hmm...
-                let root = src.file_syntax(db.upcast());
-                src.map(|ast| match ast.to_node(&root) {
-                    Either::Left(ast::Pat::IdentPat(it)) => Either::Left(it),
-                    Either::Left(_) => unreachable!("local with non ident-pattern"),
-                    Either::Right(it) => Either::Right(it),
+        match body.self_param.zip(source_map.self_param_syntax()) {
+            Some((param, source)) if param == self.binding_id => {
+                let root = source.file_syntax(db.upcast());
+                LocalSource {
+                    local: self,
+                    source: source.map(|ast| Either::Right(ast.to_node(&root))),
+                }
+            }
+            _ => body[self.binding_id]
+                .definitions
+                .first()
+                .map(|&definition| {
+                    let src = source_map.pat_syntax(definition).unwrap(); // Hmm...
+                    let root = src.file_syntax(db.upcast());
+                    LocalSource {
+                        local: self,
+                        source: src.map(|ast| match ast.to_node(&root) {
+                            ast::Pat::IdentPat(it) => Either::Left(it),
+                            _ => unreachable!("local with non ident-pattern"),
+                        }),
+                    }
                 })
-            })
-            .map(move |source| LocalSource { local: self, source })
+                .unwrap(),
+        }
     }
 }
 
diff --git a/crates/hir/src/semantics/source_to_def.rs b/crates/hir/src/semantics/source_to_def.rs
index 4733ea5a35..d4d6f0b243 100644
--- a/crates/hir/src/semantics/source_to_def.rs
+++ b/crates/hir/src/semantics/source_to_def.rs
@@ -101,7 +101,7 @@ use hir_def::{
 use hir_expand::{attrs::AttrId, name::AsName, HirFileId, HirFileIdExt, MacroCallId};
 use rustc_hash::FxHashMap;
 use smallvec::SmallVec;
-use stdx::{impl_from, never};
+use stdx::impl_from;
 use syntax::{
     ast::{self, HasName},
     AstNode, SyntaxNode,
@@ -253,14 +253,8 @@ impl SourceToDefCtx<'_, '_> {
         src: InFile<ast::SelfParam>,
     ) -> Option<(DefWithBodyId, BindingId)> {
         let container = self.find_pat_or_label_container(src.syntax())?;
-        let (body, source_map) = self.db.body_with_source_map(container);
-        let pat_id = source_map.node_self_param(src.as_ref())?;
-        if let crate::Pat::Bind { id, .. } = body[pat_id] {
-            Some((container, id))
-        } else {
-            never!();
-            None
-        }
+        let body = self.db.body(container);
+        Some((container, body.self_param?))
     }
     pub(super) fn label_to_def(
         &mut self,
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index f87e0a3897..dc96a1b03d 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -219,11 +219,10 @@ impl SourceAnalyzer {
     pub(crate) fn type_of_self(
         &self,
         db: &dyn HirDatabase,
-        param: &ast::SelfParam,
+        _param: &ast::SelfParam,
     ) -> Option<Type> {
-        let src = InFile { file_id: self.file_id, value: param };
-        let pat_id = self.body_source_map()?.node_self_param(src)?;
-        let ty = self.infer.as_ref()?[pat_id].clone();
+        let binding = self.body()?.self_param?;
+        let ty = self.infer.as_ref()?[binding].clone();
         Some(Type::new_with_resolver(db, &self.resolver, ty))
     }
 
diff --git a/crates/ide/src/inlay_hints/implicit_drop.rs b/crates/ide/src/inlay_hints/implicit_drop.rs
index 8d9ad5bda1..5ba4e514e1 100644
--- a/crates/ide/src/inlay_hints/implicit_drop.rs
+++ b/crates/ide/src/inlay_hints/implicit_drop.rs
@@ -74,6 +74,10 @@ pub(super) fn hints(
                     Ok(s) => s.value.text_range(),
                     Err(_) => continue,
                 },
+                MirSpan::SelfParam => match source_map.self_param_syntax() {
+                    Some(s) => s.value.text_range(),
+                    None => continue,
+                },
                 MirSpan::Unknown => continue,
             };
             let binding = &hir.bindings[*binding];
diff --git a/crates/rust-analyzer/src/main_loop.rs b/crates/rust-analyzer/src/main_loop.rs
index bca6db19dc..e106a85c6e 100644
--- a/crates/rust-analyzer/src/main_loop.rs
+++ b/crates/rust-analyzer/src/main_loop.rs
@@ -488,20 +488,22 @@ impl GlobalState {
 
     fn update_diagnostics(&mut self) {
         let db = self.analysis_host.raw_database();
-        let subscriptions = self
-            .mem_docs
-            .iter()
-            .map(|path| self.vfs.read().0.file_id(path).unwrap())
-            .filter(|&file_id| {
-                let source_root = db.file_source_root(file_id);
-                // Only publish diagnostics for files in the workspace, not from crates.io deps
-                // or the sysroot.
-                // While theoretically these should never have errors, we have quite a few false
-                // positives particularly in the stdlib, and those diagnostics would stay around
-                // forever if we emitted them here.
-                !db.source_root(source_root).is_library
-            })
-            .collect::<Vec<_>>();
+        let subscriptions = {
+            let vfs = &self.vfs.read().0;
+            self.mem_docs
+                .iter()
+                .map(|path| vfs.file_id(path).unwrap())
+                .filter(|&file_id| {
+                    let source_root = db.file_source_root(file_id);
+                    // Only publish diagnostics for files in the workspace, not from crates.io deps
+                    // or the sysroot.
+                    // While theoretically these should never have errors, we have quite a few false
+                    // positives particularly in the stdlib, and those diagnostics would stay around
+                    // forever if we emitted them here.
+                    !db.source_root(source_root).is_library
+                })
+                .collect::<Vec<_>>()
+        };
         tracing::trace!("updating notifications for {:?}", subscriptions);
 
         // Diagnostics are triggered by the user typing


Test patch:
diff --git a/crates/hir-ty/src/tests.rs b/crates/hir-ty/src/tests.rs
index 5e159236f4..1cae8eaeac 100644
--- a/crates/hir-ty/src/tests.rs
+++ b/crates/hir-ty/src/tests.rs
@@ -293,20 +293,29 @@ fn infer_with_mismatches(content: &str, include_mismatches: bool) -> String {
         let mut types: Vec<(InFile<SyntaxNode>, &Ty)> = Vec::new();
         let mut mismatches: Vec<(InFile<SyntaxNode>, &TypeMismatch)> = Vec::new();
 
+        if let Some(self_param) = body.self_param {
+            let ty = &inference_result.type_of_binding[self_param];
+            if let Some(syntax_ptr) = body_source_map.self_param_syntax() {
+                let root = db.parse_or_expand(syntax_ptr.file_id);
+                let node = syntax_ptr.map(|ptr| ptr.to_node(&root).syntax().clone());
+                types.push((node.clone(), ty));
+            }
+        }
+
         for (pat, mut ty) in inference_result.type_of_pat.iter() {
             if let Pat::Bind { id, .. } = body.pats[pat] {
                 ty = &inference_result.type_of_binding[id];
             }
-            let syntax_ptr = match body_source_map.pat_syntax(pat) {
+            let node = match body_source_map.pat_syntax(pat) {
                 Ok(sp) => {
                     let root = db.parse_or_expand(sp.file_id);
                     sp.map(|ptr| ptr.to_node(&root).syntax().clone())
                 }
                 Err(SyntheticSyntax) => continue,
             };
-            types.push((syntax_ptr.clone(), ty));
+            types.push((node.clone(), ty));
             if let Some(mismatch) = inference_result.type_mismatch_for_pat(pat) {
-                mismatches.push((syntax_ptr, mismatch));
+                mismatches.push((node, mismatch));
             }
         }
 
diff --git a/crates/hir-ty/src/tests/simple.rs b/crates/hir-ty/src/tests/simple.rs
index ffd6a6051b..917e9f4408 100644
--- a/crates/hir-ty/src/tests/simple.rs
+++ b/crates/hir-ty/src/tests/simple.rs
@@ -2121,6 +2121,7 @@ async fn main() {
         "#,
         expect![[r#"
             16..193 '{     ...2 }; }': ()
+            16..193 '{     ...2 }; }': impl Future<Output = ()>
             26..27 'x': i32
             30..43 'unsafe { 92 }': i32
             39..41 '92': i32
@@ -2131,6 +2132,8 @@ async fn main() {
             73..75 '()': ()
             95..96 'z': ControlFlow<(), ()>
             130..140 'try { () }': ControlFlow<(), ()>
+            130..140 'try { () }': fn from_output<ControlFlow<(), ()>>(<ControlFlow<(), ()> as Try>::Output) -> ControlFlow<(), ()>
+            130..140 'try { () }': ControlFlow<(), ()>
             136..138 '()': ()
             150..151 'w': i32
             154..166 'const { 92 }': i32