Change:
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Adding more methods in trait creates more ICE :eyes: <details<summary<strongBacktrace</strong</summary<p</p</details

Discussion:
/// } /// ``` pub fn get_fn_id_for_return_block(self, id: HirId) -> Option<HirId> { <del> let mut iter = self.parent_iter(id).peekable(); let mut ignore_tail = false; if let Node::Expr(Expr { kind: ExprKind::Ret(_), .. }) = self.tcx.hir_node(id) { // When dealing with `return` statements, we don't care about climbing only tail // expressions. ignore_tail = true; } </del> <ins> let enclosing_body_owner = self.tcx.local_def_id_to_hir_id(self.enclosing_body_owner(id)); // Return `None` if the `id` expression is not the returned value of the enclosing body let mut iter = [id].into_iter().chain(self.parent_id_iter(id)).peekable(); while let Some(cur_id) = iter.next() { if enclosing_body_owner == cur_id { break; } // A return statement is always the value returned from the enclosing body regardless of // what the parent expressions are. if let Node::Expr(Expr { kind: ExprKind::Ret(_), .. }) = self.tcx.hir_node(cur_id) { break; } </ins> <del> let mut prev_hir_id = None; while let Some((hir_id, node)) = iter.next() { if let (Some((_, next_node)), false) = (iter.peek(), ignore_tail) { match next_node { Node::Block(Block { expr: None, .. }) => return None, // The current node is not the tail expression of its parent. Node::Block(Block { expr: Some(e), .. }) if hir_id != e.hir_id => return None, </del> <ins> // If the current expression's value doesnt get used as the parent expressions value then return `None` if let Some(&parent_id) = iter.peek() { match self.tcx.hir_node(parent_id) { // The current node is not the tail expression of the block expression parent expr. Node::Block(Block { expr: Some(e), .. }) if cur_id != e.hir_id => return None, </ins> Node::Block(Block { expr: Some(e), .. }) if matches!(e.kind, ExprKind::If(_, _, None)) => { return None; } <ins> // The current expression's value does not pass up through these parent expressions Node::Block(Block { expr: None, .. }) | Node::Expr(Expr { kind: ExprKind::Loop(..), .. }) | Node::LetStmt(..) => return None, </ins> _ => {} } } <del> match node { Node::Item(_) | Node::ForeignItem(_) | Node::TraitItem(_) | Node::Expr(Expr { kind: ExprKind::Closure(_), .. }) | Node::ImplItem(_) // The input node `id` must be enclosed in the method's body as opposed // to some other place such as its return type (fixes #114918). // We verify that indirectly by checking that the previous node is the // current node's body if node.body_id().map(|b| b.hir_id) == prev_hir_id =>  { return Some(hir_id) } // Ignore `return`s on the first iteration Node::Expr(Expr { kind: ExprKind::Loop(..) | ExprKind::Ret(..), .. }) | Node::LetStmt(_) => { return None; } _ => {} } prev_hir_id = Some(hir_id); </del> } <del> None </del> <ins> Some(enclosing_body_owner) </ins> } /// Retrieves the `OwnerId` for `id`'s parent item, or `id` itself if no

<del> //@ known-bug: rust-lang/rust#128810 #![feature(fn_delegation)] use std::marker::PhantomData; pub struct InvariantRef<'a, T: ?Sized>(&'a T, PhantomData<&'a mut &'a T>); impl<'a> InvariantRef<'a, ()> { pub const NEW: Self = InvariantRef::new(&()); } trait Trait { fn foo(&self) -> u8 { 0 } fn bar(&self) -> u8 { 1 } fn meh(&self) -> u8 { 2 } } struct Z(u8); impl Trait for Z { reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } } fn main() { } </del>

<ins> #![feature(fn_delegation)] #![allow(incomplete_features)] use std::marker::PhantomData; pub struct InvariantRef<'a, T: ?Sized>(&'a T, PhantomData<&'a mut &'a T>); impl<'a> InvariantRef<'a, ()> { pub const NEW: Self = InvariantRef::new(&()); //~^ ERROR: no function or associated item named `new` found } trait Trait { fn foo(&self) -> u8 { 0 } fn bar(&self) -> u8 { 1 } fn meh(&self) -> u8 { 2 } } struct Z(u8); impl Trait for Z { reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } //~^ ERROR: use of undeclared lifetime name `'a` //~| ERROR: use of undeclared lifetime name `'a` //~| ERROR: use of undeclared lifetime name `'a` //~| ERROR: the trait bound `u8: Trait` is not satisfied //~| ERROR: the trait bound `u8: Trait` is not satisfied //~| ERROR: the trait bound `u8: Trait` is not satisfied //~| ERROR: mismatched types //~| ERROR: mismatched types //~| ERROR: mismatched types } fn main() { } </ins>

<ins> error[E0261]: use of undeclared lifetime name `'a` --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:68 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |                                                                    ^^ undeclared lifetime | help: consider introducing lifetime `'a` here | LL |     reuse <u8 as Trait>::{foo'a, , bar, meh} { &const { InvariantRef::<'a>::NEW } } |                              +++ help: consider introducing lifetime `'a` here | LL | impl<'a> Trait for Z { |     ++++ error[E0261]: use of undeclared lifetime name `'a` --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:68 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |                                                                    ^^ undeclared lifetime | help: consider introducing lifetime `'a` here | LL |     reuse <u8 as Trait>::{foo, bar'a, , meh} { &const { InvariantRef::<'a>::NEW } } |                                   +++ help: consider introducing lifetime `'a` here | LL | impl<'a> Trait for Z { |     ++++ error[E0261]: use of undeclared lifetime name `'a` --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:68 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |                                                                    ^^ undeclared lifetime | help: consider introducing lifetime `'a` here | LL |     reuse <u8 as Trait>::{foo, bar, meh'a, } { &const { InvariantRef::<'a>::NEW } } |                                        +++ help: consider introducing lifetime `'a` here | LL | impl<'a> Trait for Z { |     ++++ error[E0599]: no function or associated item named `new` found for struct `InvariantRef` in the current scope --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:9:41 | LL | pub struct InvariantRef<'a, T: ?Sized>(&'a T, PhantomData<&'a mut &'a T>); | -------------------------------------- function or associated item `new` not found for this struct ... LL |     pub const NEW: Self = InvariantRef::new(&()); |                                         ^^^ function or associated item not found in `InvariantRef<'_, _>` error[E0308]: mismatched types --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:53 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |                                                     ^^^^^^^^^^^^^^^^^^^^^^^ expected `u8`, found `InvariantRef<'_, ()>` | = note: expected type `u8` found struct `InvariantRef<'_, ()>` error[E0277]: the trait bound `u8: Trait` is not satisfied --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:12 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |            ^^ the trait `Trait` is not implemented for `u8` | = help: the trait `Trait` is implemented for `Z` error[E0308]: mismatched types --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:53 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |                                                     ^^^^^^^^^^^^^^^^^^^^^^^ expected `u8`, found `InvariantRef<'_, ()>` | = note: expected type `u8` found struct `InvariantRef<'_, ()>` = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` error[E0277]: the trait bound `u8: Trait` is not satisfied --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:12 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |            ^^ the trait `Trait` is not implemented for `u8` | = help: the trait `Trait` is implemented for `Z` = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` error[E0308]: mismatched types --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:53 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |                                                     ^^^^^^^^^^^^^^^^^^^^^^^ expected `u8`, found `InvariantRef<'_, ()>` | = note: expected type `u8` found struct `InvariantRef<'_, ()>` = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` error[E0277]: the trait bound `u8: Trait` is not satisfied --> $DIR/correct_body_owner_parent_found_in_diagnostics.rs:22:12 | LL |     reuse <u8 as Trait>::{foo, bar, meh} { &const { InvariantRef::<'a>::NEW } } |            ^^ the trait `Trait` is not implemented for `u8` | = help: the trait `Trait` is implemented for `Z` = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` error: aborting due to 10 previous errors Some errors have detailed explanations: E0261, E0277, E0308, E0599. For more information about an error, try `rustc --explain E0261`. </ins>

<ins> fn generic<const N: u32>() {} trait Collate<const A: u32> { type Pass; fn collate(self) -> Self::Pass; } impl<const B: u32> Collate<B> for i32 { type Pass = (); fn collate(self) -> Self::Pass { generic::<{ true }>() //~^ ERROR: mismatched types } } fn main() {} </ins>

<ins> error[E0308]: mismatched types --> $DIR/const-in-fn-call-generics.rs:11:21 | LL |         generic::<{ true }>() |                     ^^^^ expected `u32`, found `bool` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0308`. </ins>