Revise never type fallback algorithm#88804

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bors merged 7 commits intorust-lang:masterfrom

Mark-Simulacrum:never-algo-v2

Sep 24, 2021

Commits on Sep 17, 2021

introduce new fallback algorithm

nikomatsakis
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remove diverging type variables from fn check

nikomatsakis
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Mark-Simulacrum
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remove reliance on "diverging" type variables

nikomatsakis
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Mark-Simulacrum
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stop categorizing inference variables as diverging when created

nikomatsakis
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optimization: use a single DepthFirstSearch instead of hashsets

nikomatsakis
authored and
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Add another case of fallback to () avoid breakage
Mark-Simulacrum
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Add nofallback tests
Mark-Simulacrum
committed