Forbid trailing attributes in impl blocks

Closes #20711

src/libcore/str/mod.rs

@@ -1616,13 +1616,15 @@ impl<'a> Iterator for Lines<'a> {
     fn next(&mut self) -> Option<&'a str> { self.inner.next() }
     #[inline]
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
+}
 
-#[stable]}
+#[stable]
 impl<'a> DoubleEndedIterator for Lines<'a> {
     #[inline]
     fn next_back(&mut self) -> Option<&'a str> { self.inner.next_back() }
+}
 
-#[stable]}
+#[stable]
 impl<'a> Iterator for LinesAny<'a> {
     type Item = &'a str;
 
@@ -1630,8 +1632,9 @@ impl<'a> Iterator for LinesAny<'a> {
     fn next(&mut self) -> Option<&'a str> { self.inner.next() }
     #[inline]
     fn size_hint(&self) -> (uint, Option<uint>) { self.inner.size_hint() }
+}
 
-#[stable]}
+#[stable]
 impl<'a> DoubleEndedIterator for LinesAny<'a> {
     #[inline]
     fn next_back(&mut self) -> Option<&'a str> { self.inner.next_back() }

src/libsyntax/parse/parser.rs

@@ -4769,8 +4769,12 @@ fn parse_impl_items(&mut self) -> (Vec<ImplItem>, Vec<Attribute>) {
         self.expect(&token::OpenDelim(token::Brace));
         let (inner_attrs, mut method_attrs) =
             self.parse_inner_attrs_and_next();
-        while !self.eat(&token::CloseDelim(token::Brace)) {
+        loop {
             method_attrs.extend(self.parse_outer_attributes().into_iter());
+            if method_attrs.is_empty() && self.eat(&token::CloseDelim(token::Brace)) {
+                break;
+            }
+
             let vis = self.parse_visibility();
             if self.eat_keyword(keywords::Type) {
                 impl_items.push(TypeImplItem(P(self.parse_typedef(
@@ -4781,7 +4785,7 @@ fn parse_impl_items(&mut self) -> (Vec<ImplItem>, Vec<Attribute>) {
                             method_attrs,
                             vis)));
             }
-            method_attrs = self.parse_outer_attributes();
+            method_attrs = vec![];
         }
         (impl_items, inner_attrs)
     }

src/test/compile-fail/issue-20711-2.rs

+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct Foo;
+
+impl Foo {
+    fn foo() {}
+
+    #[stable]
+} //~ ERROR expected `fn`, found `}`
+
+fn main() {}
+

src/test/compile-fail/issue-20711.rs

+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+struct Foo;
+
+impl Foo {
+    #[stable]
+} //~ ERROR expected `fn`, found `}`
+
+fn main() {}