Specialize a few tests depending on opt-level.

src/test/ui/polymorphization/predicates.rs

@@ -1,5 +1,6 @@
 // build-fail
-// compile-flags:-Zpolymorphize=on
+// compile-flags: -Copt-level=0 -Zpolymorphize=on
+
 #![feature(rustc_attrs)]
 
 // This test checks that `T` is considered used in `foo`, because it is used in a predicate for

src/test/ui/polymorphization/predicates.stderr

@@ -1,31 +1,17 @@
 error: item has unused generic parameters
-  --> $DIR/predicates.rs:58:4
-   |
-LL | fn quux<A, B, C: Default>() -> usize
-   |    ^^^^ -  - generic parameter `B` is unused
-   |         |
-   |         generic parameter `A` is unused
-
-error: item has unused generic parameters
-  --> $DIR/predicates.rs:75:4
-   |
-LL | fn foobar<F, G>() -> usize
-   |    ^^^^^^ - generic parameter `F` is unused
-
-error: item has unused generic parameters
-  --> $DIR/predicates.rs:14:4
+  --> $DIR/predicates.rs:15:4
    |
 LL | fn foo<I, T>(_: I)
    |    ^^^    - generic parameter `T` is unused
 
 error: item has unused generic parameters
-  --> $DIR/predicates.rs:23:4
+  --> $DIR/predicates.rs:24:4
    |
 LL | fn baz<I, T>(_: I)
    |    ^^^    - generic parameter `T` is unused
 
 error: item has unused generic parameters
-  --> $DIR/predicates.rs:44:19
+  --> $DIR/predicates.rs:45:19
    |
 LL | impl<'a, I, T: 'a, E> Iterator for Foo<'a, I, E>
    |          -         - generic parameter `E` is unused
@@ -36,13 +22,27 @@ LL |         self.find(|_| true)
    |                   ^^^^^^^^
 
 error: item has unused generic parameters
-  --> $DIR/predicates.rs:9:4
+  --> $DIR/predicates.rs:59:4
+   |
+LL | fn quux<A, B, C: Default>() -> usize
+   |    ^^^^ -  - generic parameter `B` is unused
+   |         |
+   |         generic parameter `A` is unused
+
+error: item has unused generic parameters
+  --> $DIR/predicates.rs:76:4
+   |
+LL | fn foobar<F, G>() -> usize
+   |    ^^^^^^ - generic parameter `F` is unused
+
+error: item has unused generic parameters
+  --> $DIR/predicates.rs:10:4
    |
 LL | fn bar<I>() {
    |    ^^^ - generic parameter `I` is unused
 
 note: the above error was encountered while instantiating `fn foo::<std::slice::Iter<u32>, T>`
-  --> $DIR/predicates.rs:85:5
+  --> $DIR/predicates.rs:86:5
    |
 LL |     foo(x.iter());
    |     ^^^^^^^^^^^^^