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Rollup merge of #101556 - compiler-errors:tweak-generator-print, r=jackh726

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Tweak future opaque ty pretty printing

1. The `Return` type of a generator doesn't need to be a lang item just for diagnostic printing of types
2. We shouldn't suppress the `Output = Ty` of a opaque future if the type is a int or float var.
This commit is contained in:
Matthias Krüger 2022-09-09 07:02:32 +02:00 • committed by GitHub
commit bdfbc3597b
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5 changed files with 7 additions and 7 deletions
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1
compiler/rustc_hir/src/lang_items.rs
View file

@ -238,7 +238,6 @@ language_item_table! {
Future, sym::future_trait, future_trait, Target::Trait, GenericRequirement::Exact(0); Future, sym::future_trait, future_trait, Target::Trait, GenericRequirement::Exact(0);
GeneratorState, sym::generator_state, gen_state, Target::Enum, GenericRequirement::None; GeneratorState, sym::generator_state, gen_state, Target::Enum, GenericRequirement::None;
Generator, sym::generator, gen_trait, Target::Trait, GenericRequirement::Minimum(1); Generator, sym::generator, gen_trait, Target::Trait, GenericRequirement::Minimum(1);
GeneratorReturn, sym::generator_return, generator_return, Target::AssocTy, GenericRequirement::None;
Unpin, sym::unpin, unpin_trait, Target::Trait, GenericRequirement::None; Unpin, sym::unpin, unpin_trait, Target::Trait, GenericRequirement::None;
Pin, sym::pin, pin_type, Target::Struct, GenericRequirement::None; Pin, sym::pin, pin_type, Target::Struct, GenericRequirement::None;

8
compiler/rustc_middle/src/ty/print/pretty.rs
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@ -916,12 +916,14 @@ pub trait PrettyPrinter<'tcx>:
// Skip printing `<[generator@] as Generator<_>>::Return` from async blocks, // Skip printing `<[generator@] as Generator<_>>::Return` from async blocks,
// unless we can find out what generator return type it comes from. // unless we can find out what generator return type it comes from.
let term = if let Some(ty) = term.skip_binder().ty() let term = if let Some(ty) = term.skip_binder().ty()
&& let ty::Projection(ty::ProjectionTy { item_def_id, substs }) = ty.kind() && let ty::Projection(proj) = ty.kind()
&& Some(*item_def_id) == tcx.lang_items().generator_return() && let assoc = tcx.associated_item(proj.item_def_id)
&& assoc.trait_container(tcx) == tcx.lang_items().gen_trait()
&& assoc.name == rustc_span::sym::Return
{ {
if let ty::Generator(_, substs, _) = substs.type_at(0).kind() { if let ty::Generator(_, substs, _) = substs.type_at(0).kind() {
let return_ty = substs.as_generator().return_ty(); let return_ty = substs.as_generator().return_ty();
if !return_ty.is_ty_infer() { if !return_ty.is_ty_var() {
return_ty.into() return_ty.into()
} else { } else {
continue; continue;

1
compiler/rustc_span/src/symbol.rs
View file

@ -763,7 +763,6 @@ symbols! {
gen_future, gen_future,
gen_kill, gen_kill,
generator, generator,
generator_return,
generator_state, generator_state,
generators, generators,
generic_arg_infer, generic_arg_infer,

2
library/core/src/ops/generator.rs
View file

@ -83,7 +83,7 @@ pub trait Generator<R = ()> {
/// `return` statement or implicitly as the last expression of a generator /// `return` statement or implicitly as the last expression of a generator
/// literal. For example futures would use this as `Result<T, E>` as it /// literal. For example futures would use this as `Result<T, E>` as it
/// represents a completed future. /// represents a completed future.
#[lang = "generator_return"] #[cfg_attr(bootstrap, lang = "generator_return")]
type Return; type Return;
/// Resumes the execution of this generator. /// Resumes the execution of this generator.

2
src/test/ui/suggestions/expected-boxed-future-isnt-pinned.stderr
View file

@ -91,7 +91,7 @@ LL | pub const fn from_generator<T>(gen: T) -> impl Future<Output = T::Return>
| ------------------------------- the found opaque type | ------------------------------- the found opaque type
| |
= note: expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>` = note: expected struct `Pin<Box<(dyn Future<Output = i32> + Send + 'static)>>`
found opaque type `impl Future` found opaque type `impl Future<Output = {integer}>`
help: you need to pin and box this expression help: you need to pin and box this expression
| |
LL ~ Box::pin(async { LL ~ Box::pin(async {