From 7892cc3c5f6532a18338ce989ea1639af5e417b4 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 31 Jan 2023 02:59:36 +0000
Subject: [PATCH] Do not depend on Generator trait when deducing closure
signature
---
compiler/rustc_hir_typeck/src/closure.rs | 20 +++++++++---------
.../lang-items/lang-item-missing-generator.rs | 21 -------------------
.../lang-item-missing-generator.stderr | 15 -------------
3 files changed, 10 insertions(+), 46 deletions(-)
delete mode 100644 tests/ui/lang-items/lang-item-missing-generator.rs
delete mode 100644 tests/ui/lang-items/lang-item-missing-generator.stderr
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs
index 329b69eff54..90c4e5b6540 100644
--- a/compiler/rustc_hir_typeck/src/closure.rs
+++ b/compiler/rustc_hir_typeck/src/closure.rs
@@ -15,6 +15,7 @@ use rustc_middle::ty::visit::TypeVisitable;
use rustc_middle::ty::{self, Ty, TypeSuperVisitable, TypeVisitor};
use rustc_span::def_id::LocalDefId;
use rustc_span::source_map::Span;
+use rustc_span::sym;
use rustc_target::spec::abi::Abi;
use rustc_trait_selection::traits;
use rustc_trait_selection::traits::error_reporting::ArgKind;
@@ -288,21 +289,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let trait_def_id = projection.trait_def_id(tcx);
let is_fn = tcx.is_fn_trait(trait_def_id);
- let gen_trait = tcx.require_lang_item(LangItem::Generator, cause_span);
- let is_gen = gen_trait == trait_def_id;
+
+ let gen_trait = tcx.lang_items().gen_trait();
+ let is_gen = gen_trait == Some(trait_def_id);
+
if !is_fn && !is_gen {
debug!("not fn or generator");
return None;
}
- if is_gen {
- // Check that we deduce the signature from the `<_ as std::ops::Generator>::Return`
- // associated item and not yield.
- let return_assoc_item = self.tcx.associated_item_def_ids(gen_trait)[1];
- if return_assoc_item != projection.projection_def_id() {
- debug!("not return assoc item of generator");
- return None;
- }
+ // Check that we deduce the signature from the `<_ as std::ops::Generator>::Return`
+ // associated item and not yield.
+ if is_gen && self.tcx.associated_item(projection.projection_def_id()).name != sym::Return {
+ debug!("not `Return` assoc item of `Generator`");
+ return None;
}
let input_tys = if is_fn {
diff --git a/tests/ui/lang-items/lang-item-missing-generator.rs b/tests/ui/lang-items/lang-item-missing-generator.rs
deleted file mode 100644
index 9b9aff38e52..00000000000
--- a/tests/ui/lang-items/lang-item-missing-generator.rs
+++ /dev/null
@@ -1,21 +0,0 @@
-// error-pattern: requires `generator` lang_item
-#![feature(no_core, lang_items, unboxed_closures, tuple_trait)]
-#![no_core]
-
-#[lang = "sized"] pub trait Sized { }
-
-#[lang = "tuple_trait"] pub trait Tuple { }
-
-#[lang = "fn_once"]
-#[rustc_paren_sugar]
-pub trait FnOnce<Args: Tuple> {
- type Output;
-
- extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
-}
-
-pub fn abc() -> impl FnOnce(f32) {
- |_| {}
-}
-
-fn main() {}
diff --git a/tests/ui/lang-items/lang-item-missing-generator.stderr b/tests/ui/lang-items/lang-item-missing-generator.stderr
deleted file mode 100644
index a24fdb5fb65..00000000000
--- a/tests/ui/lang-items/lang-item-missing-generator.stderr
+++ /dev/null
@@ -1,15 +0,0 @@
-error[E0635]: unknown feature `tuple_trait`
- --> $DIR/lang-item-missing-generator.rs:2:51
- |
-LL | #![feature(no_core, lang_items, unboxed_closures, tuple_trait)]
- | ^^^^^^^^^^^
-
-error: requires `generator` lang_item
- --> $DIR/lang-item-missing-generator.rs:17:17
- |
-LL | pub fn abc() -> impl FnOnce(f32) {
- | ^^^^^^^^^^^^^^^^
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0635`.