diff --git a/src/lib/cc/ctassert.h b/src/lib/cc/ctassert.h
index bedf0b83a6..d9d3aa40b0 100644
--- a/src/lib/cc/ctassert.h
+++ b/src/lib/cc/ctassert.h
@@ -46,7 +46,7 @@
 
 #define CTASSERT_EXPN(x, a, b) CTASSERT_DECL(x, a, b)
 #define CTASSERT_DECL(x, a, b) \
-  typedef char tor_ctassert_##a##_##b[(x) ? 1 : -1] ATTR_UNUSED
+  typedef char tor_ctassert_##a##_##b[(x) ? 1 : -1] ATTR_UNUSED; EAT_SEMICOLON
 
 #endif /* __STDC_VERSION__ >= 201112L */