diff --git a/src/core/inttypes.c b/src/core/inttypes.c
index f6f07c13..78c39fe0 100644
--- a/src/core/inttypes.c
+++ b/src/core/inttypes.c
@@ -580,7 +580,7 @@ DIVMETHODINVERT(uint64_t, u64, mod, %)
 OPMETHOD(uint64_t, u64, and, &)
 OPMETHOD(uint64_t, u64, or, |)
 OPMETHOD(uint64_t, u64, xor, ^)
-UNARYMETHOD(int64_t, u64, not, ~)
+UNARYMETHOD(uint64_t, u64, not, ~)
 OPMETHOD(uint64_t, u64, lshift, <<)
 OPMETHOD(uint64_t, u64, rshift, >>)