Resolve is not detecting out-of-scope type parameters

[nikomatsakis]

There is currently some incorrect code in substitutions attempting to check for out-of-scope type parameters by detecting out-of-bounds indices. This is the wrong phase; this sort of lexical binding stuff is supposed to be handled by resolve. I have a fix coming in a PR today.

Here is a test that incorrectly compiles today as a result:

trait Trait<A> {
    fn outer(self) {
        enum Foo<B> {
            Variance(A)
        }
    }
}

fn main() { }