6 files changed, 138 insertions, 0 deletions
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden.rs b/tests/ui/type-alias-impl-trait/hkl_forbidden.rs
new file mode 100644
index 00000000000..c6d1202ef85
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden.rs
@@ -0,0 +1,39 @@
+#![feature(type_alias_impl_trait)]
+
+fn id(s: &str) -> &str {
+    s
+}
+
+type Opaque<'a> = impl Sized + 'a;
+
+fn test(s: &str) -> (impl Fn(&str) -> Opaque<'_>, impl Fn(&str) -> Opaque<'_>) {
+    (id, id) //~ ERROR expected generic lifetime parameter, found `'_`
+}
+
+fn id2<'a, 'b>(s: (&'a str, &'b str)) -> (&'a str, &'b str) {
+    s
+}
+
+type Opaque2<'a> = impl Sized + 'a;
+
+fn test2() -> impl for<'a, 'b> Fn((&'a str, &'b str)) -> (Opaque2<'a>, Opaque2<'b>) {
+    id2 //~ ERROR expected generic lifetime parameter, found `'a`
+}
+
+type Opaque3<'a> = impl Sized + 'a;
+
+fn test3(s: &str) -> (impl Fn(&str) -> Opaque3<'_>, Opaque3<'_>) {
+    (id, s) //~ ERROR expected generic lifetime parameter, found `'_`
+}
+
+type Opaque4<'a> = impl Sized + 'a;
+fn test4(s: &str) -> (Opaque4<'_>, impl Fn(&str) -> Opaque4<'_>) {
+    (s, id) //~ ERROR expected generic lifetime parameter, found `'_`
+}
+
+type Inner<'a> = impl Sized;
+fn outer_impl() -> impl for<'a> Fn(&'a ()) -> Inner<'a> {
+    |x| x //~ ERROR expected generic lifetime parameter, found `'a`
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden.stderr b/tests/ui/type-alias-impl-trait/hkl_forbidden.stderr
new file mode 100644
index 00000000000..d49be73d94e
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden.stderr
@@ -0,0 +1,48 @@
+error[E0792]: expected generic lifetime parameter, found `'_`
+  --> $DIR/hkl_forbidden.rs:10:5
+   |
+LL | type Opaque<'a> = impl Sized + 'a;
+   |             -- this generic parameter must be used with a generic lifetime parameter
+...
+LL |     (id, id)
+   |     ^^^^^^^^
+
+error[E0792]: expected generic lifetime parameter, found `'a`
+  --> $DIR/hkl_forbidden.rs:20:5
+   |
+LL | type Opaque2<'a> = impl Sized + 'a;
+   |              -- this generic parameter must be used with a generic lifetime parameter
+...
+LL |     id2
+   |     ^^^
+
+error[E0792]: expected generic lifetime parameter, found `'_`
+  --> $DIR/hkl_forbidden.rs:26:5
+   |
+LL | type Opaque3<'a> = impl Sized + 'a;
+   |              -- this generic parameter must be used with a generic lifetime parameter
+...
+LL |     (id, s)
+   |     ^^^^^^^
+
+error[E0792]: expected generic lifetime parameter, found `'_`
+  --> $DIR/hkl_forbidden.rs:31:5
+   |
+LL | type Opaque4<'a> = impl Sized + 'a;
+   |              -- this generic parameter must be used with a generic lifetime parameter
+LL | fn test4(s: &str) -> (Opaque4<'_>, impl Fn(&str) -> Opaque4<'_>) {
+LL |     (s, id)
+   |     ^^^^^^^
+
+error[E0792]: expected generic lifetime parameter, found `'a`
+  --> $DIR/hkl_forbidden.rs:36:5
+   |
+LL | type Inner<'a> = impl Sized;
+   |            -- this generic parameter must be used with a generic lifetime parameter
+LL | fn outer_impl() -> impl for<'a> Fn(&'a ()) -> Inner<'a> {
+LL |     |x| x
+   |     ^^^^^
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden2.rs b/tests/ui/type-alias-impl-trait/hkl_forbidden2.rs
new file mode 100644
index 00000000000..69493f0855f
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden2.rs
@@ -0,0 +1,18 @@
+#![feature(type_alias_impl_trait)]
+//~^ ERROR: expected generic lifetime parameter, found `'a`
+
+type Opaque<'a> = impl Sized + 'a;
+
+trait Trait<'a> {
+    type Assoc;
+}
+
+impl<'a> Trait<'a> for () {
+    type Assoc = ();
+}
+
+fn test() -> &'static dyn for<'a> Trait<'a, Assoc = Opaque<'a>> {
+    &()
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden2.stderr b/tests/ui/type-alias-impl-trait/hkl_forbidden2.stderr
new file mode 100644
index 00000000000..ed0b2085c88
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden2.stderr
@@ -0,0 +1,5 @@
+error[E0792]: expected generic lifetime parameter, found `'a`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden3.rs b/tests/ui/type-alias-impl-trait/hkl_forbidden3.rs
new file mode 100644
index 00000000000..a4148599f77
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden3.rs
@@ -0,0 +1,13 @@
+#![feature(type_alias_impl_trait)]
+
+type Opaque<'a> = impl Sized + 'a;
+
+fn foo<'a>(x: &'a ()) -> &'a () {
+    x
+}
+
+fn test() -> for<'a> fn(&'a ()) -> Opaque<'a> {
+    foo //~ ERROR: mismatched types
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden3.stderr b/tests/ui/type-alias-impl-trait/hkl_forbidden3.stderr
new file mode 100644
index 00000000000..d262177a86b
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden3.stderr
@@ -0,0 +1,15 @@
+error[E0308]: mismatched types
+  --> $DIR/hkl_forbidden3.rs:10:5
+   |
+LL | type Opaque<'a> = impl Sized + 'a;
+   |                   --------------- the expected opaque type
+...
+LL |     foo
+   |     ^^^ one type is more general than the other
+   |
+   = note: expected fn pointer `for<'a> fn(&'a ()) -> Opaque<'a>`
+              found fn pointer `for<'a> fn(&'a ()) -> &'a ()`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.