rustc: feature gates errors should use the new attribute syntax

Author: erickt

src/librustc/front/feature_gate.rs

@@ -16,7 +16,7 @@
 //! enabled.
 //!
 //! Features are enabled in programs via the crate-level attributes of
-//! #[feature(...)] with a comma-separated list of features.
+//! #![feature(...)] with a comma-separated list of features.
 
 use middle::lint;
 
@@ -324,7 +324,7 @@ pub fn check_crate(sess: &Session, krate: &ast::Crate) {
         match attr.meta_item_list() {
             None => {
                 sess.span_err(attr.span, "malformed feature attribute, \
-                                          expected #[feature(...)]");
+                                          expected #![feature(...)]");
             }
             Some(list) => {
                 for &mi in list.iter() {

src/librustc/middle/typeck/astconv.rs

@@ -219,7 +219,7 @@ fn ast_path_substs<AC:AstConv,RS:RegionScope>(
         && !this.tcx().sess.features.default_type_params.get() {
         this.tcx().sess.span_err(path.span, "default type parameters are \
                                              experimental and possibly buggy");
-        this.tcx().sess.span_note(path.span, "add #[feature(default_type_params)] \
+        this.tcx().sess.span_note(path.span, "add #![feature(default_type_params)] \
                                               to the crate attributes to enable");
     }