const fn: allow use of trait impls from bounds

src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.rs

@@ -0,0 +1,26 @@
+// FIXME(jschievink): this is not rejected correctly (only when the non-const impl is actually used)
+// ignore-test
+
+#![feature(const_fn)]
+#![feature(const_trait_impl)]
+#![allow(incomplete_features)]
+
+struct S;
+
+impl PartialEq for S {
+    fn eq(&self, _: &S) -> bool {
+        true
+    }
+}
+
+const fn equals_self<T: PartialEq>(t: &T) -> bool {
+    true
+}
+
+// Calling `equals_self` with something that has a non-const impl should throw an error, despite
+// it not using the impl.
+
+pub const EQ: bool = equals_self(&S);
+//~^ ERROR
+
+fn main() {}