From c9889b02b92d28ab4b97bd3c57f4fd06e801697d Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Sat, 13 Apr 2024 06:17:07 +0000
Subject: [PATCH 1/2] fix coroutine witness doctest
---
compiler/rustc_type_ir/src/ty_kind.rs | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/compiler/rustc_type_ir/src/ty_kind.rs b/compiler/rustc_type_ir/src/ty_kind.rs
index 56ae7ad9f74..397e104512f 100644
--- a/compiler/rustc_type_ir/src/ty_kind.rs
+++ b/compiler/rustc_type_ir/src/ty_kind.rs
@@ -181,9 +181,9 @@ pub enum TyKind<I: Interner> {
/// Looking at the following example, the witness for this coroutine
/// may end up as something like `for<'a> [Vec<i32>, &'a Vec<i32>]`:
///
- /// ```ignore UNSOLVED (ask @compiler-errors, should this error? can we just swap the yields?)
+ /// ```
/// #![feature(coroutines)]
- /// |a| {
+ /// static |a| {
/// let x = &vec![3];
/// yield a;
/// yield x[0];
From c6a4f810d926d00a176de40ae78288c145f3843d Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Sat, 13 Apr 2024 07:26:47 +0000
Subject: [PATCH 2/2] Replace a `DefiningOpaqueTypes::No` with `Yes` by
asserting that one side of the comparison is a type variable.
Thus there will never be an opaque type involved in a way that constrains its hidden type, as the other side of the comparison is always a generator witness type
---
compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
index da46ed07690..2580179ce5b 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs
@@ -561,9 +561,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// Unify `interior` with `witness` and collect all the resulting obligations.
let span = self.tcx.hir().body(body_id).value.span;
+ let ty::Infer(ty::InferTy::TyVar(_)) = interior.kind() else {
+ span_bug!(span, "coroutine interior witness not infer: {:?}", interior.kind())
+ };
let ok = self
.at(&self.misc(span), self.param_env)
- .eq(DefineOpaqueTypes::No, interior, witness)
+ // Will never define opaque types, as all we do is instantiate a type variable.
+ .eq(DefineOpaqueTypes::Yes, interior, witness)
.expect("Failed to unify coroutine interior type");
let mut obligations = ok.obligations;