[Haskell-cafe] wildcards for type variables?

[Evan Laforge]

Occasionally I have a function with an unused argument, whose type I
don't want to restrict.  Thus:

f :: _unused -> A -> B
f _ a = b

Since it's a little unusual, I try to make it clear that the type is
intentionally ignored.  But it makes me wonder, would it make sense to
allow _ as a type variable name, with the same meaning as in pattern
matching?