fix rust-lang#95310: ICE about async generators

Author: frank-king

compiler/rustc_typeck/src/collect/type_of.rs

@@ -579,6 +579,9 @@ fn find_opaque_ty_constraints(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Ty<'_> {
                 debug!("no constraints in typeck results");
                 return;
             }
+            if matches!(self.tcx.type_of(def_id).kind(), ty::Error(..)) {
+                self.tcx.sess.abort_if_errors();
+            }
             // Use borrowck to get the type with unerased regions.
             let concrete_opaque_types = &self.tcx.mir_borrowck(def_id).concrete_opaque_types;
             debug!(?concrete_opaque_types);

src/test/ui/generator/async-generator-issue-95310.rs

@@ -0,0 +1,28 @@
+#![crate_type="lib"]
+#![feature(generators)]
+#![feature(generic_associated_types)]
+#![feature(type_alias_impl_trait)]
+
+// edition:2021
+
+trait Service {
+    type Future<'f>: std::future::Future + 'f
+    where
+        Self: 'f;
+
+    fn spawn<'f>(&'f mut self) -> Self::Future<'f>;
+}
+
+struct Blah;
+
+impl Service for Blah {
+    type Future<'f> = impl std::future::Future<Output = &'static i32> + 'f;
+
+    fn spawn<'f>(&'f mut self) -> Self::Future<'f> {
+        //~^ ERROR: type mismatch resolving
+        async move {
+            //~^ ERROR: type mismatch resolving 
+            yield &1; //~ ERROR: `async` generators are not yet supported
+        }
+    }
+}

src/test/ui/generator/async-generator-issue-95310.stderr

@@ -0,0 +1,32 @@
+error[E0727]: `async` generators are not yet supported
+  --> $DIR/async-generator-issue-95310.rs:25:13
+   |
+LL |             yield &1;
+   |             ^^^^^^^^
+
+error[E0271]: type mismatch resolving `<[static generator@$DIR/async-generator-issue-95310.rs:23:20: 26:10] as Generator<ResumeTy>>::Yield == ()`
+  --> $DIR/async-generator-issue-95310.rs:23:20
+   |
+LL |           async move {
+   |  ____________________^
+LL | |
+LL | |             yield &1;
+LL | |         }
+   | |_________^ expected `()`, found `&{integer}`
+   |
+note: required by a bound in `from_generator`
+  --> $SRC_DIR/core/src/future/mod.rs:LL:COL
+   |
+LL |     T: Generator<ResumeTy, Yield = ()>,
+   |                            ^^^^^^^^^^ required by this bound in `from_generator`
+
+error[E0271]: type mismatch resolving `<impl Future<Output = [async output]> as Future>::Output == &'static i32`
+  --> $DIR/async-generator-issue-95310.rs:21:35
+   |
+LL |     fn spawn<'f>(&'f mut self) -> Self::Future<'f> {
+   |                                   ^^^^^^^^^^^^^^^^ expected `&i32`, found `()`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0271, E0727.
+For more information about an error, try `rustc --explain E0271`.