correct various error messages that changed

The new messages seem universally better. I think these result because
we recognize that we are in an invariant context more often.

src/test/compile-fail/region-invariant-static-error-reporting.rs

@@ -13,9 +13,8 @@
 // over time, but this test used to exhibit some pretty bogus messages
 // that were not remotely helpful.
 
-// error-pattern:cannot infer
-// error-pattern:cannot outlive the lifetime 'a
-// error-pattern:must be valid for the static lifetime
+// error-pattern:the lifetime 'a
+// error-pattern:the static lifetime
 
 struct Invariant<'a>(Option<&'a mut &'a mut ()>);
 

src/test/compile-fail/regions-trait-object-subtyping.rs

@@ -22,7 +22,7 @@ fn foo2<'a:'b,'b>(x: &'b mut (Dummy+'a)) -> &'b mut (Dummy+'b) {
 
 fn foo3<'a,'b>(x: &'a mut Dummy) -> &'b mut Dummy {
     // Without knowing 'a:'b, we can't coerce
-    x //~ ERROR cannot infer an appropriate lifetime
+    x //~ ERROR lifetime bound not satisfied
      //~^ ERROR cannot infer an appropriate lifetime
 }
 

src/test/compile-fail/variance-contravariant-arg-object.rs

@@ -21,15 +21,15 @@ fn get_min_from_max<'min, 'max>(v: Box<Get<&'max i32>>)
                                 -> Box<Get<&'min i32>>
     where 'max : 'min
 {
-    v //~ ERROR cannot infer an appropriate lifetime
+    v //~ ERROR mismatched types
 }
 
 fn get_max_from_min<'min, 'max, G>(v: Box<Get<&'min i32>>)
                                    -> Box<Get<&'max i32>>
     where 'max : 'min
 {
     // Previously OK:
-    v //~ ERROR cannot infer an appropriate lifetime
+    v //~ ERROR mismatched types
 }
 
 fn main() { }

src/test/compile-fail/variance-covariant-arg-object.rs

@@ -22,14 +22,14 @@ fn get_min_from_max<'min, 'max>(v: Box<Get<&'max i32>>)
     where 'max : 'min
 {
     // Previously OK, now an error as traits are invariant.
-    v //~ ERROR cannot infer an appropriate lifetime
+    v //~ ERROR mismatched types
 }
 
 fn get_max_from_min<'min, 'max, G>(v: Box<Get<&'min i32>>)
                                    -> Box<Get<&'max i32>>
     where 'max : 'min
 {
-    v //~ ERROR cannot infer an appropriate lifetime
+    v //~ ERROR mismatched types
 }
 
 fn main() { }

src/test/compile-fail/variance-invariant-arg-object.rs

@@ -18,14 +18,14 @@ fn get_min_from_max<'min, 'max>(v: Box<Get<&'max i32>>)
                                 -> Box<Get<&'min i32>>
     where 'max : 'min
 {
-    v //~ ERROR cannot infer an appropriate lifetime
+    v //~ ERROR mismatched types
 }
 
 fn get_max_from_min<'min, 'max, G>(v: Box<Get<&'min i32>>)
                                    -> Box<Get<&'max i32>>
     where 'max : 'min
 {
-    v //~ ERROR cannot infer an appropriate lifetime
+    v //~ ERROR mismatched types
 }
 
 fn main() { }