let predicates_of = tcx.predicates_of(def_id);
debug!("instantiate_opaque_types: predicates={:#?}", predicates_of,);
let bounds = predicates_of.instantiate(tcx, substs);
+
+ let param_env = tcx.param_env(def_id);
+ let InferOk { value: bounds, obligations } =
+ infcx.partially_normalize_associated_types_in(span, self.body_id, param_env, &bounds);
+ self.obligations.extend(obligations);
+
debug!("instantiate_opaque_types: bounds={:?}", bounds);
let required_region_bounds = tcx.required_region_bounds(ty, bounds.predicates.clone());
&declared_ret_ty,
decl.output.span(),
);
+ debug!("check_fn: declared_ret_ty: {}, revealed_ret_ty: {}", declared_ret_ty, revealed_ret_ty);
fcx.ret_coercion = Some(RefCell::new(CoerceMany::new(revealed_ret_ty)));
fn_sig = fcx.tcx.mk_fn_sig(
fn_sig.inputs().iter().cloned(),
--- /dev/null
+// check-pass
+// edition:2018
+
+#![feature(async_await)]
+
+// See issue 60414
+
+trait Trait {
+ type Assoc;
+}
+
+async fn foo<T: Trait<Assoc=()>>() -> T::Assoc {
+ ()
+}
+
+fn main() {}
--- /dev/null
+// compile-fail
+// edition:2018
+
+#![feature(async_await)]
+#![feature(existential_type)]
+#![feature(impl_trait_in_bindings)]
+//~^ WARNING the feature `impl_trait_in_bindings` is incomplete
+
+// See issue 60414
+
+/////////////////////////////////////////////
+// Reduction to `impl Trait`
+
+struct Foo<T>(T);
+
+trait FooLike { type Output; }
+
+impl<T> FooLike for Foo<T> {
+ type Output = T;
+}
+
+mod impl_trait {
+ use super::*;
+
+ trait Trait {
+ type Assoc;
+ }
+
+ /// `T::Assoc` can't be normalized any further here.
+ fn foo_fail<T: Trait>() -> impl FooLike<Output=T::Assoc> {
+ //~^ ERROR: type mismatch
+ Foo(())
+ }
+}
+
+/////////////////////////////////////////////
+// Same with lifetimes in the trait
+
+mod lifetimes {
+ use super::*;
+
+ trait Trait<'a> {
+ type Assoc;
+ }
+
+ /// Missing bound constraining `Assoc`, `T::Assoc` can't be normalized further.
+ fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike<Output=T::Assoc> {
+ //~^ ERROR: type mismatch
+ Foo(())
+ }
+}
+
+fn main() {}
--- /dev/null
+warning: the feature `impl_trait_in_bindings` is incomplete and may cause the compiler to crash
+ --> $DIR/bound-normalization-fail.rs:6:12
+ |
+LL | #![feature(impl_trait_in_bindings)]
+ | ^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0271]: type mismatch resolving `<Foo<()> as FooLike>::Output == <T as impl_trait::Trait>::Assoc`
+ --> $DIR/bound-normalization-fail.rs:30:32
+ |
+LL | fn foo_fail<T: Trait>() -> impl FooLike<Output=T::Assoc> {
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected (), found associated type
+ |
+ = note: expected type `()`
+ found type `<T as impl_trait::Trait>::Assoc`
+ = note: the return type of a function must have a statically known size
+
+error[E0271]: type mismatch resolving `<Foo<()> as FooLike>::Output == <T as lifetimes::Trait<'static>>::Assoc`
+ --> $DIR/bound-normalization-fail.rs:47:41
+ |
+LL | fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike<Output=T::Assoc> {
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected (), found associated type
+ |
+ = note: expected type `()`
+ found type `<T as lifetimes::Trait<'static>>::Assoc`
+ = note: the return type of a function must have a statically known size
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0271`.
--- /dev/null
+// check-pass
+// edition:2018
+
+#![feature(async_await)]
+#![feature(existential_type)]
+#![feature(impl_trait_in_bindings)]
+//~^ WARNING the feature `impl_trait_in_bindings` is incomplete
+
+// See issue 60414
+
+/////////////////////////////////////////////
+// Reduction to `impl Trait`
+
+struct Foo<T>(T);
+
+trait FooLike { type Output; }
+
+impl<T> FooLike for Foo<T> {
+ type Output = T;
+}
+
+mod impl_trait {
+ use super::*;
+
+ trait Trait {
+ type Assoc;
+ }
+
+ /// `T::Assoc` should be normalized to `()` here.
+ fn foo_pass<T: Trait<Assoc=()>>() -> impl FooLike<Output=T::Assoc> {
+ Foo(())
+ }
+}
+
+/////////////////////////////////////////////
+// Same with lifetimes in the trait
+
+mod lifetimes {
+ use super::*;
+
+ trait Trait<'a> {
+ type Assoc;
+ }
+
+ /// Like above.
+ ///
+ /// FIXME(#51525) -- the shorter notation `T::Assoc` winds up referencing `'static` here
+ fn foo2_pass<'a, T: Trait<'a, Assoc=()> + 'a>(
+ ) -> impl FooLike<Output=<T as Trait<'a>>::Assoc> + 'a {
+ Foo(())
+ }
+
+ /// Normalization to type containing bound region.
+ ///
+ /// FIXME(#51525) -- the shorter notation `T::Assoc` winds up referencing `'static` here
+ fn foo2_pass2<'a, T: Trait<'a, Assoc=&'a ()> + 'a>(
+ ) -> impl FooLike<Output=<T as Trait<'a>>::Assoc> + 'a {
+ Foo(&())
+ }
+}
+
+/////////////////////////////////////////////
+// Reduction using `impl Trait` in bindings
+
+mod impl_trait_in_bindings {
+ struct Foo;
+
+ trait FooLike { type Output; }
+
+ impl FooLike for Foo {
+ type Output = u32;
+ }
+
+ trait Trait {
+ type Assoc;
+ }
+
+ fn foo<T: Trait<Assoc=u32>>() {
+ let _: impl FooLike<Output=T::Assoc> = Foo;
+ }
+}
+
+/////////////////////////////////////////////
+// The same applied to `existential type`s
+
+mod existential_types {
+ trait Implemented {
+ type Assoc;
+ }
+ impl<T> Implemented for T {
+ type Assoc = u8;
+ }
+
+ trait Trait {
+ type Out;
+ }
+
+ impl Trait for () {
+ type Out = u8;
+ }
+
+ existential type Ex: Trait<Out = <() as Implemented>::Assoc>;
+
+ fn define() -> Ex {
+ ()
+ }
+}
+
+fn main() {}
--- /dev/null
+warning: the feature `impl_trait_in_bindings` is incomplete and may cause the compiler to crash
+ --> $DIR/bound-normalization-pass.rs:6:12
+ |
+LL | #![feature(impl_trait_in_bindings)]
+ | ^^^^^^^^^^^^^^^^^^^^^^
+
projects / rust.git / commitdiff