Leak check in impossible_predicates to avoid monomorphizing impossible instances

2 files changed, 79 insertions, 0 deletions

diff --git a/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs
new file mode 100644
index 00000000000..bc433605531
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders-2.rs
@@ -0,0 +1,39 @@
+//@ build-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+#![allow(coherence_leak_check)]
+
+type A = fn(&'static ());
+type B = fn(&());
+
+trait Bound<P: WithAssoc>: From<GetAssoc<P>> {
+}
+impl Bound<B> for String {}
+
+trait Trt<T> {
+    fn __(&self, x: T) where T: Bound<A> {
+        T::from(());
+    }
+}
+
+impl<T, S> Trt<T> for S {}
+
+type GetAssoc<T> = <T as WithAssoc>::Ty;
+
+trait WithAssoc {
+    type Ty;
+}
+
+impl WithAssoc for B {
+    type Ty = String;
+}
+
+impl WithAssoc for A {
+    type Ty = ();
+}
+
+fn main() {
+    let x: &'static dyn Trt<String> = &();
+}
diff --git a/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs
new file mode 100644
index 00000000000..63ad1c0a060
--- /dev/null
+++ b/tests/ui/traits/trait-upcasting/impossible-method-modulo-binders.rs
@@ -0,0 +1,40 @@
+//@ build-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+trait Foo {}
+impl Foo for fn(&'static ()) {}
+
+trait Bar {
+    type Assoc: Default;
+}
+impl<T: Foo> Bar for T {
+    type Assoc = usize;
+}
+impl Bar for fn(&()) {
+    type Assoc = ();
+}
+
+fn needs_foo<T: Foo>() -> usize {
+    needs_bar::<T>()
+}
+
+fn needs_bar<T: Bar>() -> <T as Bar>::Assoc {
+    Default::default()
+}
+
+trait Evil<T> {
+    fn bad(&self)
+    where
+        T: Foo,
+    {
+        needs_foo::<T>();
+    }
+}
+
+impl Evil<fn(&())> for () {}
+
+fn main() {
+    let x: &dyn Evil<fn(&())> = &();
+}