Skip const-eval if evaluatable predicate is trivial#127242
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dingxiangfei2009 wants to merge 1 commit intorust-lang:masterfrom
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Skip const-eval if evaluatable predicate is trivial#127242dingxiangfei2009 wants to merge 1 commit intorust-lang:masterfrom
dingxiangfei2009 wants to merge 1 commit intorust-lang:masterfrom
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Some changes occurred in cc @BoxyUwU |
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I think there is not much point in landing this for a few reasons:
generic_const_exprsis very unstable and this is likely to not be the final design so investing time (and code complexity) into small performance optimizations does not seem worth it to me- Logic for equating consts already has a similar special case to this that will check for
==and short circuit and returnOkif its true. - I would expect that this method of solving that ICE is masking an underlying issue, but I would have to poke at the example a bit more to figure out exactly what's going on
Regardless thanks for the interest in const generics :3
| if tcx.features().generic_const_exprs { | ||
| let ct = tcx.expand_abstract_consts(unexpanded_ct); | ||
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| if trivially_satisfied_from_param_env(ct, param_env) { |
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This would have had to go before the expand_abstract_consts call as otherwise its never going to find any matches in the env since abstract consts arent expanded in the ParamEnv :3
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☔ The latest upstream changes (presumably #125915) made this pull request unmergeable. Please resolve the merge conflicts. |
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Closing this so it's not in my list of assigned PRs anymore 😅 Feel free to reopen if you disagree with my comments and would like to continue this |
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It appears that
ConstEvaluatablepredicate is given already inParamEnvduring type-checking in well-formness checks. This is an attempt at simplifying the checks.Fix #123959