Disallow generic arguments in path of a macro invocation
diff --git a/src/mac.rs b/src/mac.rs
index b17a466..2ccc8c9 100644
--- a/src/mac.rs
+++ b/src/mac.rs
@@ -73,7 +73,7 @@
 
     impl Synom for Macro {
         named!(parse -> Self, do_parse!(
-            what: syn!(Path) >>
+            what: call!(Path::parse_mod_style) >>
             bang: punct!(!) >>
             body: call!(tt::delimited) >>
             (Macro {