Address @catamorphism's error message grammar nit.

src/librustc/middle/resolve.rs

@@ -3827,7 +3827,7 @@ pub fn resolve_trait_reference(@mut self,
                 let path_str = self.idents_to_str(trait_reference.path.idents);
 
                 let usage_str = match reference_type {
-                    TraitBoundingTypeParameter => "bound type parameter to",
+                    TraitBoundingTypeParameter => "bound type parameter with",
                     TraitImplementation        => "implement",
                     TraitDerivation            => "derive"
                 };

src/test/compile-fail/resolve-unknown-trait.rs

@@ -16,5 +16,5 @@ impl SomeNonExistentTrait for int {}
 //~^ ERROR attempt to implement a nonexistent trait `SomeNonExistentTrait`
 
 fn f<T:SomeNonExistentTrait>() {}
-//~^ ERROR attempt to bound type parameter to a nonexistent trait `SomeNonExistentTrait`
+//~^ ERROR attempt to bound type parameter with a nonexistent trait `SomeNonExistentTrait`