1 files changed, 40 insertions, 0 deletions
diff --git a/tests/ui/nll/user-annotations/normalization-infer.rs b/tests/ui/nll/user-annotations/normalization-infer.rs
new file mode 100644
index 00000000000..8bfc272d4ba
--- /dev/null
+++ b/tests/ui/nll/user-annotations/normalization-infer.rs
@@ -0,0 +1,40 @@
+// Annnotations may contain projection types with inference variables as input.
+// Make sure we don't get ambiguities when normalizing them.
+
+// check-fail
+
+// Single impl.
+fn test1<A, B, C, D>(a: A, b: B, c: C) {
+    trait Tr { type Ty; }
+    impl<T: 'static> Tr for (T,) { type Ty = T; }
+
+    let _: <(_,) as Tr>::Ty = a; //~ ERROR type `A`
+    Some::<<(_,) as Tr>::Ty>(b); //~ ERROR type `B`
+    || -> <(_,) as Tr>::Ty { c }; //~ ERROR type `C`
+    |d: <(_,) as Tr>::Ty| -> D { d }; //~ ERROR type `D`
+}
+
+
+// Two impls. The selected impl depends on the actual type.
+fn test2<A, B, C>(a: A, b: B, c: C) {
+    trait Tr { type Ty; }
+    impl<T: 'static> Tr for (u8, T) { type Ty = T; }
+    impl<T>          Tr for (i8, T) { type Ty = T; }
+    type Alias<X, Y> = (<(X, Y) as Tr>::Ty, X);
+
+    fn temp() -> String { todo!() }
+
+    // `u8` impl, requires static.
+    let _: Alias<_, _> = (a, 0u8); //~ ERROR type `A`
+    Some::<Alias<_, _>>((b, 0u8)); //~ ERROR type `B`
+    || -> Alias<_, _> { (c, 0u8) }; //~ ERROR type `C`
+
+    let _: Alias<_, _> = (&temp(), 0u8); //~ ERROR temporary value
+    Some::<Alias<_, _>>((&temp(), 0u8)); //~ ERROR temporary value
+
+    // `i8` impl, no region constraints.
+    let _: Alias<_, _> = (&temp(), 0i8);
+    Some::<Alias<_, _>>((&temp(), 0i8));
+}
+
+fn main() {}