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-rw-r--r--tests/ui/impl-trait/hidden-type-is-opaque-2.rs45
1 files changed, 45 insertions, 0 deletions
diff --git a/tests/ui/impl-trait/hidden-type-is-opaque-2.rs b/tests/ui/impl-trait/hidden-type-is-opaque-2.rs
new file mode 100644
index 000000000..970d84120
--- /dev/null
+++ b/tests/ui/impl-trait/hidden-type-is-opaque-2.rs
@@ -0,0 +1,45 @@
+// This doesn't work, because we don't flow information from opaque types
+// into function arguments via the function's generic parameters
+// FIXME(oli-obk): make `expected_inputs_for_expected_output` support this
+
+#![feature(type_alias_impl_trait)]
+
+fn reify_as() -> Thunk<impl FnOnce(Continuation) -> Continuation> {
+ Thunk::new(|mut cont| {
+ cont.reify_as(); //~ ERROR type annotations needed
+ cont
+ })
+}
+
+type Tait = impl FnOnce(Continuation) -> Continuation;
+
+fn reify_as_tait() -> Thunk<Tait> {
+ Thunk::new(|mut cont| {
+ cont.reify_as(); //~ ERROR type annotations needed
+ cont
+ })
+}
+
+#[must_use]
+struct Thunk<F>(F);
+
+impl<F> Thunk<F> {
+ fn new(f: F) -> Self
+ where
+ F: ContFn,
+ {
+ Thunk(f)
+ }
+}
+
+trait ContFn {}
+
+impl<F: FnOnce(Continuation) -> Continuation> ContFn for F {}
+
+struct Continuation;
+
+impl Continuation {
+ fn reify_as(&mut self) {}
+}
+
+fn main() {}