diff --git a/src/grammar/mod.rs b/src/grammar/mod.rs
index a4275e8..93414a3 100644
--- a/src/grammar/mod.rs
+++ b/src/grammar/mod.rs
@@ -70,7 +70,7 @@ impl Buffer {
 }
 
 macro_rules! string {
-    ($($kind:ty),*) => (
+    ($($kind:path),*) => (
         $(
             impl<'l> $kind for &'l str {
                 #[inline]