Combine some tests

Author: tiif

tests/ui/internal/unstable-impl-cannot-use-feature.stderr renamed to tests/ui/internal/unstable-impl-cannot-use-feature.fail.stderr

@@ -1,11 +1,11 @@
 error[E0284]: type annotations needed: cannot satisfy `unstable feature: `feat_foo``
-  --> $DIR/unstable-impl-cannot-use-feature.rs:23:5
+  --> $DIR/unstable-impl-cannot-use-feature.rs:26:5
    |
 LL |     Bar::foo();
    |     ^^^ cannot satisfy `unstable feature: `feat_foo``
    |
 note: required for `Bar` to implement `Foo`
-  --> $DIR/unstable-impl-cannot-use-feature.rs:18:6
+  --> $DIR/unstable-impl-cannot-use-feature.rs:20:6
    |
 LL | #[unstable_feature_bound(feat_foo)]
    | ----------------------------------- unsatisfied trait bound introduced here

tests/ui/internal/unstable-impl-cannot-use-feature.rs

@@ -1,27 +1,30 @@
+//@ revisions: pass fail
+//@[pass] check-pass
+
 #![allow(internal_features)]
 #![feature(staged_api)]
 #![feature(impl_stability)]
 #![allow(dead_code)]
-#![feature(feat_foo)]
+#![cfg_attr(fail, feature(feat_foo))]
 #![unstable(feature = "feat_foo", issue = "none" )]
 
-/// In staged-api crate, impl that is marked with #[unstable_feature_bound(..)]
-/// cannot be enabled with #[feature(..)]
+/// In staged-api crate, using an unstable impl requires
+/// #[unstable_feature_bound(..)], not  #[feature(..)].
 
 pub trait Foo {
     fn foo();
 }
 pub struct Bar;
 
-// Annotate the impl as unstable.
 #[unstable_feature_bound(feat_foo)]
 impl Foo for Bar {
     fn foo() {}
 }
 
+#[cfg_attr(pass, unstable_feature_bound(feat_foo))]
 fn bar() {
     Bar::foo();
-    //~^ ERROR: cannot satisfy `unstable feature: `feat_foo``
+    //[fail]~^ ERROR: cannot satisfy `unstable feature: `feat_foo``
 }
 
 fn main() {}