Opportunistically resolve region var in canonicalizer (instead of resolving root var) #118964
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Rollup of 2 pull requests Successful merges: - rust-lang#118927 (Erase late bound regions from `Instance::fn_sig()` and add a few more details to StableMIR APIs) - rust-lang#118964 (Opportunistically resolve region var in canonicalizer (instead of resolving root var)) r? `@ghost` `@rustbot` modify labels: rollup
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Rollup merge of rust-lang#118964 - compiler-errors:resolve, r=aliemjay Opportunistically resolve region var in canonicalizer (instead of resolving root var) See comment in `compiler/rustc_type_ir/src/infcx.rs`. The **root** infer region for a given region vid may not actually be nameable from the universe of the original vid. That means that the assertion in the canonicalizer was too strict, since the `EagerResolver` that we use before canonicalizing is doing only as much resolving as it can. This replaces `resolve_lt_var` and `probe_lt_var` in the `rustc_type_ir` API with `opportunistic_resolve_lt_var`, which acts as you expect it should. I left a FIXME that complains about the inconsistency. This test is really gnarly, but I have no idea how to minimize it, since it seems to kind of just be coincidental that it triggered this issue. I hope the underlying root cause is easy enough to understand, though. r? `@lcnr` or `@aliemjay` Fixes rust-lang#118950
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See comment in
compiler/rustc_type_ir/src/infcx.rs.The root infer region for a given region vid may not actually be nameable from the universe of the original vid. That means that the assertion in the canonicalizer was too strict, since the
EagerResolverthat we use before canonicalizing is doing only as much resolving as it can.This replaces
resolve_lt_varandprobe_lt_varin therustc_type_irAPI withopportunistic_resolve_lt_var, which acts as you expect it should. I left a FIXME that complains about the inconsistency.This test is really gnarly, but I have no idea how to minimize it, since it seems to kind of just be coincidental that it triggered this issue. I hope the underlying root cause is easy enough to understand, though.
r? @lcnr or @aliemjay
Fixes #118950