Rollup of 9 pull requests

src/libsyntax/parse/parser.rs

@@ -5985,6 +5985,10 @@ impl<'a> Parser<'a> {
  return Ok(Some(self.parse_item_foreign_fn(visibility, lo, attrs)?));
  }
 
+ if self.check_keyword(keywords::Const) {
+ return Err(self.span_fatal(self.span, "extern items cannot be `const`"));
+ }
+
  // FIXME #5668: this will occur for a macro invocation:
  match self.parse_macro_use_or_failure(attrs, true, false, lo, visibility)? {
  Some(item) => {

src/test/parse-fail/removed-syntax-extern-const.rs

@@ -12,5 +12,5 @@
 
 extern {
  const i: isize;
- //~^ ERROR expected one of `fn`, `pub`, `static`, or `}`, found `const`
+ //~^ ERROR extern items cannot be `const`
 }