1const Foo = extern struct {
 2    f: *const fn () void,
 3};
 4
 5export fn entry() void {
 6    _ = (Foo{}).f;
 7}
 8
 9// error
10//
11// :2:8: error: extern structs cannot contain fields of type '*const fn () void'
12// :2:8: note: extern function must specify calling convention