Fix a failing test due to increased collection laziness

Author: varkor

src/test/ui/feature-gate/stability-attribute-consistency.rs

@@ -11,6 +11,12 @@
 #![stable(feature = "stable_test_feature", since = "1.0.0")]
 
 #![feature(staged_api)]
+// Right now, stability attributes are only checked for consistency if we're
+// collecting lib feature attributes, for performance. We collect lib
+// feature attributes if there are non-lang feature attributes, or a crate
+// that depends on the current one has non-lang feature attributes. Thus,
+// we're enabling an arbitrary lib feature to force the check to kick in.
+#![feature(rustc_private)]
 
 #[stable(feature = "foo", since = "1.0.0")]
 fn foo_stable_1_0_0() {}

src/test/ui/feature-gate/stability-attribute-consistency.stderr

@@ -1,11 +1,11 @@
 error[E0711]: feature `foo` is declared stable since 1.29.0, but was previously declared stable since 1.0.0
-  --> $DIR/stability-attribute-consistency.rs:18:1
+  --> $DIR/stability-attribute-consistency.rs:24:1
    |
 LL | #[stable(feature = "foo", since = "1.29.0")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0711]: feature `foo` is declared unstable, but was previously declared stable
-  --> $DIR/stability-attribute-consistency.rs:22:1
+  --> $DIR/stability-attribute-consistency.rs:28:1
    |
 LL | #[unstable(feature = "foo", issue = "0")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^