Summary:
When clang instantiates template function with argument pack, it will
give the same name to all parameters coming from the pack. To avoid
name collisions, always add index of argument's position to mangled part
of the variable.
Seemingly unrelated changes are to make existing tests pass (don't use
simple variable name where it matters)
Reviewed By: dulmarod
Differential Revision: D3503608
fbshipit-source-id: 794093a
Andrzej Kotulski