Using [] or .foo on $$ functions would not raise error but instead crash #2919.

test/test_suite/builtins/builtin_props.c3

@@ -0,0 +1,5 @@
+fn int main()
+{
+	if ($$veccompne.type == int.typeid) // #error:  A builtin has no support for properties
+	return 0;
+}

test/test_suite/builtins/builtin_subscript.c3

@@ -0,0 +1,13 @@
+fn void main()
+{
+	$$veccompgt[1]; // #error: Builtins cannot be subscripted.
+}
+fn void test()
+{
+	$$veccompeq[1] = 33; // #error: Builtins cannot be subscripted.
+}
+
+fn void test2()
+{
+	$$veccomple[..] = 52; // #error: A builtin cannot be sliced.
+}