pytorch

3fce612c - preserve original tensoriterator behavior when not explicitly promoting (#28231)

preserve original tensoriterator behavior when not explicitly promoting (#28231) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/28231 Fix: https://github.com/pytorch/pytorch/issues/28010 A mixed-type index assignment that would have been an error in 1.2 was unintentionally made possible (with incorrect results) in 1.3. This PR restores the original behavior. This is BC-breaking because: ``` a = torch.ones(5, 2, dtype=torch.double) b = torch.zeros(5, dtype=torch.int) a[:, [1]] = b.unsqueeze(-1) ``` now raises an error (as in 1.2) whereas it did not in 1.3. Test Plan: Imported from OSS Differential Revision: D18049637 Pulled By: nairbv fbshipit-source-id: 11a37dc98364ae70aac0e9dbc090d2a500aa7ccc