An empty element in a List Literal causes it to fail

(Bug, Closed -> Fixed, Priority: Critical, Test Status: Unit tested , Reported By Bad Link: Thing 3y284oe not found, )
Functions, QL
Summary: The simple reproducer is <_if(false, 1), 2, 3> -- I expect that to display 2 3, but it actually shows Expecting type Unknown Type, but actually got type Whole Number Type.
The problem is that List Literals are very strict about requiring all elements to have the same Type -- and no Type is still a Type.
It's worth noting that _concat() is more sophisticated about this, and produces the right answer. Can/should we just turn List Literals into syntax sugar for the _concat() function?