Don't emit the feature error if it's an invalid self type

Author: mikeyhew

src/librustc_typeck/check/wfcheck.rs

@@ -505,7 +505,7 @@ impl<'a, 'gcx> CheckTypeWellFormedVisitor<'a, 'gcx> {
                 .help("consider changing to `self`, `&self`, `&mut self`, or `self: Box<Self>`")
                 .code(DiagnosticId::Error("E0307".into()))
                 .emit();
-                break
+                return
             }
         }
 

src/test/compile-fail/issue-26194.rs

@@ -13,7 +13,6 @@ struct S(String);
 impl S {
     fn f(self: *mut S) -> String { self.0 }
     //~^ ERROR invalid `self` type
-    //~| ERROR arbitrary `self` types are unstable
 }
 
 fn main() { S("".to_owned()).f(); }

src/test/compile-fail/ufcs-explicit-self-bad.rs

@@ -17,7 +17,6 @@ struct Foo {
 impl Foo {
     fn foo(self: isize, x: isize) -> isize {
         //~^ ERROR invalid `self` type
-        //~| ERROR arbitrary `self` types are unstable
         self.f + x
     }
 }
@@ -29,12 +28,10 @@ struct Bar<T> {
 impl<T> Bar<T> {
     fn foo(self: Bar<isize>, x: isize) -> isize {
         //~^ ERROR invalid `self` type
-        //~| ERROR arbitrary `self` types are unstable
         x
     }
     fn bar(self: &Bar<usize>, x: isize) -> isize {
         //~^ ERROR invalid `self` type
-        //~| ERROR arbitrary `self` types are unstable
         x
     }
 }

src/test/ui/span/issue-27522.stderr

@@ -7,14 +7,5 @@ error[E0307]: invalid `self` type: &SomeType
    = note: type must be `Self` or a type that dereferences to it`
    = help: consider changing to `self`, `&self`, `&mut self`, or `self: Box<Self>`
 
-error: arbitrary `self` types are unstable (see issue #44874)
-  --> $DIR/issue-27522.rs:16:22
-   |
-16 |     fn handler(self: &SomeType);
-   |                      ^^^^^^^^^
-   |
-   = help: add #![feature(arbitrary_self_types)] to the crate attributes to enable
-   = help: consider changing to `self`, `&self`, `&mut self`, or `self: Box<Self>`
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error