1 files changed, 28 insertions, 0 deletions
diff --git a/src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original-type-alias-impl-trait.rs b/src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original-type-alias-impl-trait.rs
new file mode 100644
index 000000000..e363fdb36
--- /dev/null
+++ b/src/test/ui/impl-trait/multiple-lifetimes/ordinary-bounds-pick-original-type-alias-impl-trait.rs
@@ -0,0 +1,28 @@
+// edition:2018
+// check-pass
+
+#![feature(type_alias_impl_trait)]
+trait Trait<'a, 'b> {}
+impl<T> Trait<'_, '_> for T {}
+
+// Here we wind up selecting `'a` and `'b` in the hidden type because
+// those are the types that appear in the original values.
+
+type Foo<'a, 'b> = impl Trait<'a, 'b>;
+
+fn upper_bounds<'a, 'b>(a: &'a u8, b: &'b u8) -> Foo<'a, 'b> {
+    // In this simple case, you have a hidden type `(&'0 u8, &'1 u8)` and constraints like
+    //
+    // ```
+    // 'a: '0
+    // 'b: '1
+    // '0 in ['a, 'b]
+    // '1 in ['a, 'b]
+    // ```
+    //
+    // We use the fact that `'a: 0'` must hold (combined with the in
+    // constraint) to determine that `'0 = 'a` must be the answer.
+    (a, b)
+}
+
+fn main() {}