Split impl-with-default-fn test into a pass test and a fail test

src/test/ui/rfc-2632-const-trait-impl/impl-with-default-fn-fail.rs

@@ -0,0 +1,33 @@
+#![feature(const_trait_impl)]
+#![feature(const_fn_trait_bound)]
+
+trait Tr {
+    fn req(&self);
+
+    fn prov(&self) {
+        println!("lul");
+        self.req();
+    }
+
+    #[default_method_body_is_const]
+    fn default() {}
+}
+
+struct S;
+
+impl const Tr for S {
+    fn req(&self) {}
+} //~^^ ERROR const trait implementations may not use non-const default functions
+
+impl const Tr for u16 {
+    fn prov(&self) {}
+    fn default() {}
+} //~^^^ ERROR not all trait items implemented
+
+
+impl const Tr for u32 {
+    fn req(&self) {}
+    fn default() {}
+} //~^^^ ERROR const trait implementations may not use non-const default functions
+
+fn main() {}