Don't normalize xform_ret_ty during method candidate assembly #86506
Merged
bors merged 2 commits intorust-lang:masterfrom Oct 9, 2021
Merged
Don't normalize xform_ret_ty during method candidate assembly #86506bors merged 2 commits intorust-lang:masterfrom
bors merged 2 commits intorust-lang:masterfrom
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Fixes #85671
Normalizing the return type of a method candidate together with the expected receiver type of the method can lead to valid method candidates being rejected during probing. Specifically in the example of the fixed issue we have a
self_tyof the form&A<&[Coef]>whereas theimpl_tyof the method would be&A<_>, if we normalize the projection in the return type we unify the inference variable withCont, which will lead us to reject the candidate in the sup type check inconsider_probe. Since we don't actually need the normalized return type during candidate assembly, we postpone the normalization until we consider candidates inconsider_probe.