Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix an ICE with TAITs and Future #89946

Merged
merged 1 commit into from
Oct 17, 2021
Merged
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Fix an ICE with TAITs and Future
  • Loading branch information
JohnTitor committed Oct 16, 2021

Verified

This commit was created on GitHub.com and signed with GitHub’s verified signature. The key has expired.
commit f001e8c519c68a2233e56ea64b4bfe8c7fedf0ea
15 changes: 10 additions & 5 deletions compiler/rustc_middle/src/ty/error.rs
Original file line number Diff line number Diff line change
@@ -769,11 +769,16 @@ fn foo(&self) -> Self::T { String::new() }
) -> bool {
let assoc = self.associated_item(proj_ty.item_def_id);
if let ty::Opaque(def_id, _) = *proj_ty.self_ty().kind() {
let opaque_local_def_id = def_id.expect_local();
let opaque_hir_id = self.hir().local_def_id_to_hir_id(opaque_local_def_id);
let opaque_hir_ty = match &self.hir().expect_item(opaque_hir_id).kind {
hir::ItemKind::OpaqueTy(opaque_hir_ty) => opaque_hir_ty,
_ => bug!("The HirId comes from a `ty::Opaque`"),
let opaque_local_def_id = def_id.as_local();
let opaque_hir_ty = if let Some(opaque_local_def_id) = opaque_local_def_id {
let hir = self.hir();
let opaque_hir_id = hir.local_def_id_to_hir_id(opaque_local_def_id);
match &hir.expect_item(opaque_hir_id).kind {
hir::ItemKind::OpaqueTy(opaque_hir_ty) => opaque_hir_ty,
_ => bug!("The HirId comes from a `ty::Opaque`"),
}
} else {
return false;
};

let (trait_ref, assoc_substs) = proj_ty.trait_ref_and_own_substs(self);
24 changes: 24 additions & 0 deletions src/test/ui/type-alias-impl-trait/issue-89686.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
// edition:2018

#![feature(type_alias_impl_trait)]

use std::future::Future;

type G<'a, T> = impl Future<Output = ()>;
//~^ ERROR: type mismatch resolving `<impl Future as Future>::Output == ()`
//~| ERROR: the trait bound `T: Trait` is not satisfied

trait Trait {
type F: Future<Output = ()>;

fn f(&self) -> Self::F;

fn g<'a>(&'a self) -> G<'a, Self>
where
Self: Sized,
{
async move { self.f().await }
}
}

fn main() {}
34 changes: 34 additions & 0 deletions src/test/ui/type-alias-impl-trait/issue-89686.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,34 @@
error[E0271]: type mismatch resolving `<impl Future as Future>::Output == ()`
--> $DIR/issue-89686.rs:7:17
|
LL | type G<'a, T> = impl Future<Output = ()>;
| ^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found associated type
...
LL | async move { self.f().await }
| ------------------ the found `async` block
|
::: $SRC_DIR/core/src/future/mod.rs:LL:COL
|
LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
| ------------------------------- the found opaque type
|
= note: expected unit type `()`
found associated type `<impl Future as Future>::Output`
= help: consider constraining the associated type `<impl Future as Future>::Output` to `()`
= note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html

error[E0277]: the trait bound `T: Trait` is not satisfied
--> $DIR/issue-89686.rs:7:17
|
LL | type G<'a, T> = impl Future<Output = ()>;
| ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for `T`
|
help: consider restricting type parameter `T`
|
LL | type G<'a, T: Trait> = impl Future<Output = ()>;
| +++++++

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0271, E0277.
For more information about an error, try `rustc --explain E0271`.