tests: move coherence-subtyping from run-pass to compile-fail

This is the pattern we no longer accept.

src/test/run-pass/coherence/coherence-subtyping.rs → src/test/ui/coherence/coherence-subtyping.rs

-// run-pass
 // Test that two distinct impls which match subtypes of one another
 // yield coherence errors (or not) depending on the variance.
 
@@ -10,6 +9,7 @@ impl Contravariant for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
 }
 
 impl Contravariant for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+    //~^ ERROR
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -22,6 +22,7 @@ impl Covariant for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
 }
 
 impl Covariant for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+    //~^ ERROR
 }
 
 ///////////////////////////////////////////////////////////////////////////
@@ -34,6 +35,7 @@ impl Invariant for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
 }
 
 impl Invariant for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+    //~^ ERROR
 }
 
 fn main() { }

src/test/ui/coherence/coherence-subtyping.stderr

+error[E0119]: conflicting implementations of trait `Contravariant` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
+  --> $DIR/coherence-subtyping.rs:21:1
+   |
+LL | impl Contravariant for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
+   | -------------------------------------------------------------- first implementation here
+...
+LL | impl Contravariant for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
+
+error[E0119]: conflicting implementations of trait `Covariant` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
+  --> $DIR/coherence-subtyping.rs:34:1
+   |
+LL | impl Covariant for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
+   | ---------------------------------------------------------- first implementation here
+...
+LL | impl Covariant for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
+
+error[E0119]: conflicting implementations of trait `Invariant` for type `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`:
+  --> $DIR/coherence-subtyping.rs:47:1
+   |
+LL | impl Invariant for for<'a,'b> fn(&'a u8, &'b u8) -> &'a u8 {
+   | ---------------------------------------------------------- first implementation here
+...
+LL | impl Invariant for for<'a> fn(&'a u8, &'a u8) -> &'a u8 {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `for<'a, 'b> fn(&'a u8, &'b u8) -> &'a u8`
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0119`.