diff --git a/parrot/src/metamodel/repr.h b/parrot/src/metamodel/repr.h
index f635feb..d15d9c0 100644
--- a/parrot/src/metamodel/repr.h
+++ b/parrot/src/metamodel/repr.h
@@ -61,5 +61,5 @@ typedef struct {
     STRING * (*get_str) (PARROT_INTERP, PMC *self, PMC *Object);
 
     /* This Parrot-specific addition to the API is used to mark an object. */
-    void * (*gc_mark) (PARROT_INTERP, PMC *self, PMC *Object);
+    void (*gc_mark) (PARROT_INTERP, PMC *self, PMC *Object);
 } Rakudo_Metamodel_Representation;