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Rollup merge of #122564 - Bryanskiy:delegation-fixes, r=compiler-errors

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Delegation: fix ICE on duplicated associative items

Currently, functions delegation is only supported for delegation items with early resolved paths e.g. free functions and trait methods. During name resolution, information about function signatures is collected, including the number of parameters and whether there are self arguments. This information is then used when lowering from a delegation item into a regular function(`rustc_ast_lowering/src/delegation.rs`). The signature is usually inherited from path resolution id(`path_id`). However, in the case of trait impls `path_id` and `item_id` may be different:

```rust
trait Trait {
    fn foo(&self) -> u32 { 0 }
}

struct S;

mod to_reuse {
    use crate::S;

    pub fn foo(_: &S) -> u32 { 0 }
}

impl Trait for S {
    reuse to_reuse::foo { self }
    //~^ The signature should be inherited from item id instead of resolution id
}

```

Let's now consider an example from [issue](https://github.com/rust-lang/rust/issues/119920). Due to duplicated associative elements partial resolution for one of them will not be recorded:

9023f908cf/compiler/rustc_resolve/src/late.rs (L3153-L3162)

Which leads to an incorrect `is_in_trait_impl`

9023f908cf/compiler/rustc_ast_lowering/src/item.rs (L981-L986)

Which leads to an incorrect id for signature inheritance

9023f908cf/compiler/rustc_ast_lowering/src/delegation.rs (L99-L105)

Which lead to an ICE from original issue.

This patch fixes wrong `is_in_trait_impl`  calculation.

fixes https://github.com/rust-lang/rust/issues/119920
This commit is contained in:
León Orell Valerian Liehr 2024-03-16 23:28:48 +01:00 • committed by GitHub
commit 7b7a7fc891
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3 changed files with 52 additions and 8 deletions
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14
compiler/rustc_ast_lowering/src/item.rs
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@ -373,6 +373,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
(trait_ref, lowered_ty)
});
self.is_in_trait_impl = trait_ref.is_some();
let new_impl_items = self
.arena
.alloc_from_iter(impl_items.iter().map(|item| self.lower_impl_item_ref(item)));
@ -978,13 +979,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
}
fn lower_impl_item_ref(&mut self, i: &AssocItem) -> hir::ImplItemRef {
let trait_item_def_id = self
.resolver
.get_partial_res(i.id)
.map(|r| r.expect_full_res().opt_def_id())
.unwrap_or(None);
self.is_in_trait_impl = trait_item_def_id.is_some();
hir::ImplItemRef {
id: hir::ImplItemId { owner_id: hir::OwnerId { def_id: self.local_def_id(i.id) } },
ident: self.lower_ident(i.ident),
@ -1000,7 +994,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
},
AssocItemKind::MacCall(..) => unimplemented!(),
},
trait_item_def_id,
trait_item_def_id: self
.resolver
.get_partial_res(i.id)
.map(|r| r.expect_full_res().opt_def_id())
.unwrap_or(None),
}
}