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Rollup merge of #116039 - estebank:nested-tait, r=compiler-errors

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Account for nested `impl Trait` in TAIT

Fix #116031.

r? `@compiler-errors`
This commit is contained in:
Matthias Krüger 2023-09-22 12:15:27 +02:00 • committed by GitHub
commit fc4cfe01f6
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3 changed files with 63 additions and 2 deletions
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9
compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs
View file

@ -1,7 +1,7 @@
use rustc_errors::StashKey;
use rustc_hir::def_id::LocalDefId;
use rustc_hir::intravisit::{self, Visitor};
use rustc_hir::{self as hir, Expr, ImplItem, Item, Node, TraitItem};
use rustc_hir::{self as hir, def, Expr, ImplItem, Item, Node, TraitItem};
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt};
use rustc_span::DUMMY_SP;
@ -74,9 +74,14 @@ pub(super) fn find_opaque_ty_constraints_for_tait(tcx: TyCtxt<'_>, def_id: Local
hidden.ty
} else {
let mut parent_def_id = def_id;
while tcx.def_kind(parent_def_id) == def::DefKind::OpaqueTy {
// Account for `type Alias = impl Trait<Foo = impl Trait>;` (#116031)
parent_def_id = tcx.local_parent(parent_def_id);
}
let reported = tcx.sess.emit_err(UnconstrainedOpaqueType {
span: tcx.def_span(def_id),
name: tcx.item_name(tcx.local_parent(def_id).to_def_id()),
name: tcx.item_name(parent_def_id.to_def_id()),
what: match tcx.hir().get(scope) {
_ if scope == hir::CRATE_HIR_ID => "module",
Node::Item(hir::Item { kind: hir::ItemKind::Mod(_), .. }) => "module",

9
tests/ui/type-alias-impl-trait/nested-impl-trait-in-tait.rs Normal file
View file

@ -0,0 +1,9 @@
#![feature(type_alias_impl_trait)]
pub type Tait = impl Iterator<Item = (&'db Key, impl Iterator)>;
//~^ ERROR use of undeclared lifetime name `'db`
//~| ERROR cannot find type `Key` in this scope
//~| ERROR unconstrained opaque type
//~| ERROR unconstrained opaque type
pub fn main() {}

47
tests/ui/type-alias-impl-trait/nested-impl-trait-in-tait.stderr Normal file
View file

@ -0,0 +1,47 @@
error[E0261]: use of undeclared lifetime name `'db`
--> $DIR/nested-impl-trait-in-tait.rs:3:40
|
LL | pub type Tait = impl Iterator<Item = (&'db Key, impl Iterator)>;
| ^^^ undeclared lifetime
|
= note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the bound lifetime-generic with a new `'db` lifetime
|
LL | pub type Tait = impl for<'db> Iterator<Item = (&'db Key, impl Iterator)>;
| ++++++++
help: consider introducing lifetime `'db` here
|
LL | pub type Tait<'db> = impl Iterator<Item = (&'db Key, impl Iterator)>;
| +++++
error[E0412]: cannot find type `Key` in this scope
--> $DIR/nested-impl-trait-in-tait.rs:3:44
|
LL | pub type Tait = impl Iterator<Item = (&'db Key, impl Iterator)>;
| ^^^ not found in this scope
|
help: consider importing this struct
|
LL + use std::thread::local_impl::Key;
|
error: unconstrained opaque type
--> $DIR/nested-impl-trait-in-tait.rs:3:17
|
LL | pub type Tait = impl Iterator<Item = (&'db Key, impl Iterator)>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `Tait` must be used in combination with a concrete type within the same module
error: unconstrained opaque type
--> $DIR/nested-impl-trait-in-tait.rs:3:49
|
LL | pub type Tait = impl Iterator<Item = (&'db Key, impl Iterator)>;
| ^^^^^^^^^^^^^
|
= note: `Tait` must be used in combination with a concrete type within the same module
error: aborting due to 4 previous errors
Some errors have detailed explanations: E0261, E0412.
For more information about an error, try `rustc --explain E0261`.