Add new bytecode instructions for vec/dict/keyset
Summary:
Add new bytecode instructions CastDict, CastVec, CastKeyset to cast to
a dict, vec, or keyset. Also add Dict, Vec, and Keyset to generate literal
dicts, vecs, or keysets. Array was previously overloaded to do this, but its
cleaner to have separate instructions to distinguish them. Note that AddElemC
can be used on dicts as well. Make sure the return type is inferred from the
input rather than assuming its always an array.
Reviewed By: paulbiss
Differential Revision:
D3490107
fbshipit-source-id:
54288ef351cdb8a4b6967d205768bb2ee83de77e