1const Foo = enum { A, B, C };
 2export fn entry(foo: Foo) void {
 3    _ = foo;
 4}
 5
 6// error
 7// target=x86_64-linux
 8//
 9// :2:17: error: parameter of type 'tmp.Foo' not allowed in function with calling convention 'x86_64_sysv'
10// :2:17: note: enum tag type 'u2' is not extern compatible
11// :2:17: note: only integers with 0, 8, 16, 32, 64 and 128 bits are extern compatible
12// :1:13: note: enum declared here