Simplify TypeFreshener methods.
#150239
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Simplify TypeFreshener methods.
#150239
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`freshen_{ty,const}` take a `Result` and just do a fold if the input is
`Ok`. It's simpler to do those folds at the call site, and only call
`freshen_{ty,const}` in the `Err` case. That way we can also avoid
useless fold operations on the results of `new_{int,uint,float}`.
Also, make some `bug!` calls more concise.
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I have always found this confusingly named, because it creates a new freshener rather than returning an existing one. We can remove it and just use `TypeFreshener::new()` at the two call sites, avoiding this confusion.
lcnr
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Dec 22, 2025
lcnr
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Dec 22, 2025
Sometimes we freshen using a new `TypeFreshener`, and sometimes we freshen with an existing `TypeFreshener`. For the former we have the method `InferCtxt::freshen`. For the latter we just call `fold_with`. This asymmetry has been confusing to me. This commit removes `InferCtxt::freshen` so that all the freshening sites consistently use `fold_with` and it's obvious if each one is using a new or existing `TypeFreshener`.
Because `fresh_trait_pred` is the name of the field/argument. The `_ref` suffix appears to be a typo, or left over from earlier versions of the code.
It never happens in practice.
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| #[inline(never)] | ||
| fn fold_infer_ty(&mut self, v: ty::InferTy) -> Option<Ty<'tcx>> { | ||
| match v { | ||
| fn fold_infer_ty(&mut self, ty: ty::InferTy) -> Option<Ty<'tcx>> { |
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Yes! I have added a commit to remove the Option.
It's no longer needed.
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Thanks for the suggestions, this has ended up much nicer than the first version. |
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@bors try @rust-timer queue freshening should be at least somewhat hot? |
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Awaiting bors try build completion. @rustbot label: +S-waiting-on-perf |
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⌛ Trying commit ec5e96e with merge 1f5b4d4… To cancel the try build, run the command Workflow: https://github.com/rust-lang/rust/actions/runs/20457123989 |
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…=<try> Simplify `TypeFreshener` methods.
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Freshening is definitely hot, but freshening of inference variables is much less so. Local measurements indicated that the perf effects were negligible, but it doesn't hurt to double check. |
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💥 Test timed out after |
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@bors try |
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⌛ Trying commit ec5e96e with merge d1d7c44… To cancel the try build, run the command Workflow: https://github.com/rust-lang/rust/actions/runs/20470354760 |
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…=<try> Simplify `TypeFreshener` methods.
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freshen_{ty,const}take aResultand just do a fold if the input isOk. It's simpler to do those folds at the call site, and only callfreshen_{ty,const}in theErrcase. That way we can also avoid useless fold operations on the results ofnew_{int,uint,float}.Also, make some
bug!calls more concise.r? @lcnr