1 files changed, 55 insertions, 0 deletions
diff --git a/src/test/ui/traits/project-modulo-regions.rs b/src/test/ui/traits/project-modulo-regions.rs
new file mode 100644
index 000000000..f0c0dd3ed
--- /dev/null
+++ b/src/test/ui/traits/project-modulo-regions.rs
@@ -0,0 +1,55 @@
+// revisions: with_clause without_clause
+// Tests that `EvaluatedToOkModuloRegions` from a projection sub-obligation
+// is correctly propagated
+
+#![feature(rustc_attrs)]
+
+trait MyTrait {
+    type Assoc;
+}
+
+struct MyStruct;
+
+impl MyTrait for MyStruct {
+    // Evaluating this projection will result in `EvaluatedToOkModuloRegions`
+    // (when `with_clause` is enabled)
+    type Assoc = <Bar as MyTrait>::Assoc;
+}
+
+struct Bar;
+
+// The `where` clause on this impl will cause us to produce `EvaluatedToOkModuloRegions`
+// when evaluating a projection involving this impl
+#[cfg(with_clause)]
+impl MyTrait for Bar where for<'b> &'b (): 'b {
+    type Assoc = bool;
+}
+
+// This impl tests that the `EvaluatedToOkModuoRegions` result that we get
+// is really due to the `where` clause on the `with_clause` impl
+#[cfg(without_clause)]
+impl MyTrait for Bar {
+    type Assoc = bool;
+}
+
+// The implementation of `#[rustc_evaluate_where_clauses]` doesn't perform
+// normalization, so we need to place the projection predicate behind a normal
+// trait predicate
+struct Helper {}
+trait HelperTrait {}
+impl HelperTrait for Helper where <MyStruct as MyTrait>::Assoc: Sized {}
+
+// Evaluating this 'where' clause will (recursively) end up evaluating
+// `for<'b> &'b (): 'b`, which will produce `EvaluatedToOkModuloRegions`
+#[rustc_evaluate_where_clauses]
+fn test(val: MyStruct) where Helper: HelperTrait  {
+    panic!()
+}
+
+fn foo(val: MyStruct) {
+    test(val);
+    //[with_clause]~^     ERROR evaluate(Binder(TraitPredicate(<Helper as HelperTrait>, polarity:Positive), [])) = Ok(EvaluatedToOkModuloRegions)
+    //[without_clause]~^^ ERROR evaluate(Binder(TraitPredicate(<Helper as HelperTrait>, polarity:Positive), [])) = Ok(EvaluatedToOk)
+}
+
+fn main() {}