diff --git a/gen/abi.h b/gen/abi.h
index fd9cb635f0..2aac766b84 100644
--- a/gen/abi.h
+++ b/gen/abi.h
@@ -20,6 +20,7 @@
 #include <vector>
 
 struct Type;
+struct TypeFunction;
 struct IrFuncTyArg;
 struct DValue;