outer levels as retained rather than omitting their arguments.
This better reflects what's going on (we're performing a substitution
while still inside a template), and in theory is more correct, but I've
not found a testcase where it matters in practice (largely because we
don't allow alias templates to be declared inside a function).
Fixed AST dumping of SubstNonTypeTemplateParm[Pack]Expr to demonstrate
that we're properly substituting through dependent alias templates. (We
can't deduce properly through these yet, but we can at least produce the
right input to template argument deduction.)
No functionality change intended.
As with regular calls, we want to specialize a call that went through
template instantiation if it has an applicable OpenMP declare variant.
Reviewed By: erichkeane, mikerice
Differential Revision: https://reviews.llvm.org/D77290