How do I check if 2 unions have the same active type?

[cerulean crest]

Given 2 variables of type U (union(enum){ num: i32, str: []const u8 };). How do I check that:

var a = U{.num=3};
var b = U{.str="something"};

// How to check if a and b have the same active type? kinda like this:
// if(a.curType == b.curType)

From what I know types are tagged with an enum(backed by an int) so there should be a way to check this I assume

[severe river]

using switch

switch(a) {
 .num => {},
}

[leaden ember]

if (std.meta.activeTag(a) == b)

[severe river]

Didn't know about it

thanks!

[sand anvil]

Fengb's suggestion comes from the fact that b == .num works - which in turns works because unions have a backing enum with values that correspond to the union variant names.
activeTag(a) returns .num if U.num is set in a.