diff --git a/ccan/check_type/check_type.h b/ccan/check_type/check_type.h
index 837aef7b1..9df25a970 100644
--- a/ccan/check_type/check_type.h
+++ b/ccan/check_type/check_type.h
@@ -49,8 +49,12 @@
 #define check_type(expr, type)			\
 	((typeof(expr) *)0 != (type *)0)
 
-#define check_types_match(expr1, expr2)		\
+#define _check_types_match(expr1, expr2)		\
 	((typeof(expr1) *)0 != (typeof(expr2) *)0)
+
+#define check_types_match(expr1, expr2)                         \
+	_check_types_match((const typeof(expr1) *)0,            \
+			   (const typeof(expr2) *)0)
 #else
 #include <ccan/build_assert/build_assert.h>
 /* Without typeof, we can only test the sizes. */
diff --git a/ccan/container_of/test/compile_fail-bad-void-type.c b/ccan/container_of/test/compile_fail-bad-void-type.c
new file mode 100644
index 000000000..1faa8955d
--- /dev/null
+++ b/ccan/container_of/test/compile_fail-bad-void-type.c
@@ -0,0 +1,26 @@
+#include <ccan/container_of/container_of.h>
+#include <stdlib.h>
+
+struct foo {
+	int *a;
+	char b;
+};
+
+int main(void)
+{
+	struct foo foo = { .a = NULL, .b = 2 };
+	void *voidp = &foo.a;
+	const char *ccharp = &foo.b;
+	char *charp = &foo.b;
+	struct foo *p;
+
+#ifdef FAIL
+	/* voidp is a void * but b is an int */
+	p = container_of(voidp, struct foo, a);
+#else
+	p = voidp;
+	p = container_of(ccharp, struct foo, b);
+	p = container_of(charp, struct foo, b);
+#endif
+	return p == NULL;
+}