type a = null;
type b = false;
type c = true;
type d = nonnull;
type e = a|b|c|d;
type f = Closure<(a|b), c|d>;
type g = vec<int>;
type h = Foo<string>|Bar<nonnull>;
type i = Closure<(a|b), g>|Closure<(a|b), h>|Closure<(a|b), a|b|c>|(Foo&Bar);
type j = Closure<(a|b), i>;
type k = dict<int, iterable<int>>;
type l = "bar";
type m = 1;
type n = 1.5;
type o = 1 | 1.5 | 2 | "foo" | 2.5 | "bar";