Allow trailing commas in import lists. Closes #2582.

src/libsyntax/parse/parser.rs

@@ -2414,7 +2414,7 @@ class parser {
                   token::LBRACE {
                     let idents = self.parse_unspanned_seq(
                         token::LBRACE, token::RBRACE,
-                        seq_sep_trailing_disallowed(token::COMMA),
+                        seq_sep_trailing_allowed(token::COMMA),
                         {|p| p.parse_path_list_ident()});
                     let path = @{span: mk_sp(lo, self.span.hi),
                                  global: false, idents: path,

src/test/run-pass/import-trailing-comma.rs

@@ -0,0 +1,10 @@
+import foo::bar::{baz, quux,};
+
+mod foo {
+    mod bar {
+        fn baz() { }
+        fn quux() { }
+    }
+}
+
+fn main() { baz(); quux(); }