mapError

1 {
2     assert(ok(42).mapError!(e => e).value == 42);
3     assert(err("foo").mapError!(e => 42).error == 42);
4     version (D_Exceptions) assert(err("foo").mapError!(e => new Exception(e)).error.msg == "foo");
5 }
6 
7 // remap hook
8 {
9     static struct Hook {}
10     auto res = ok(42).mapError!(e => e, Hook);
11     assert(res == 42);
12     static assert(is(typeof(res) == Expected!(int, string, Hook)));
13 
14     auto res2 = err!int("foo").mapError!(e => "bar", Hook);
15     assert(res2.error == "bar");
16     static assert(is(typeof(res2) == Expected!(int, string, Hook)));
17 }