Hint correct extern constant syntax

kornelski · kornelski · commit ff0513c69735 · 2017-08-07T18:23:15.000+01:00
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
@@ -6007,7 +6007,9 @@ impl<'a> Parser<'a> {
         }
 
         if self.check_keyword(keywords::Const) {
-            return Err(self.span_fatal(self.span, "extern items cannot be `const`"));
+            let mut err = self.span_fatal(self.span, "extern items cannot be `const`");
+            err.help("use `static` instead");
+            return Err(err);
         }
 
         // FIXME #5668: this will occur for a macro invocation:

Original file line number	Diff line number	Diff line change
`@@ -6007,7 +6007,9 @@ impl<'a> Parser<'a> {`
`6007`	`6007`	`}`
`6008`	`6008`
`6009`	`6009`	`if self.check_keyword(keywords::Const) {`
`6010`		- return Err(self.span_fatal(self.span, "extern items cannot be `const`"));
	`6010`	+ let mut err = self.span_fatal(self.span, "extern items cannot be `const`");
	`6011`	+ err.help("use `static` instead");
	`6012`	`+ return Err(err);`
`6011`	`6013`	`}`
`6012`	`6014`
`6013`	`6015`	`// FIXME #5668: this will occur for a macro invocation:`