Add codegen test

Author: tiif

tests/ui/internal/auxiliary/unstable_impl_codegen_aux1.rs

@@ -0,0 +1,22 @@
+#![allow(internal_features)]
+#![feature(staged_api)]
+#![feature(impl_stability)]
+#![stable(feature = "a", since = "1.1.1" )]
+
+/// Aux crate for unstable impl codegen test.
+
+#[stable(feature = "a", since = "1.1.1" )]
+trait Trait {
+    fn method(&self);
+}
+
+#[unstable_feature_bound(foo)]
+impl Trait for T { 
+// FIXME: this line above failed with cannot find type `T` in this scope
+    fn method(&self) {
+        println!("hi");
+    }
+}
+
+fn main() {
+}

tests/ui/internal/auxiliary/unstable_impl_codegen_aux2.rs

@@ -0,0 +1,20 @@
+//@ aux-build:unstable_impl_codegen_aux1.rs
+
+#![allow(internal_features)]
+#![feature(staged_api)]
+#![feature(impl_stability)]
+#![stable(feature = "a", since = "1.1.1" )]
+#[feature(foo)]
+
+extern crate unstable_impl_codegen_aux1 as aux;
+
+/// Upstream crate for unstable impl codegen test 
+/// that depends on aux crate in 
+/// unstable_impl_codegen_aux1.rs
+
+fn foo<T>(a:T) {
+    a.method();
+}
+
+fn main() {
+}

tests/ui/internal/unstable_impl_codegen.rs

@@ -0,0 +1,9 @@
+//@ aux-build:unstable_impl_codegen_aux2.rs
+
+/// Downstream crate for unstable impl codegen test 
+/// that depends on upstream crate in 
+/// unstable_impl_codegen_aux2.rs
+
+fn main() {
+    foo(1_u8);
+}