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Merged
merged 1 commit into from
Aug 15, 2025

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Kivooeo
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@Kivooeo Kivooeo commented Aug 6, 2025

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rustbot commented Aug 6, 2025

WaffleLapkin is not on the review rotation at the moment.
They may take a while to respond.

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Aug 6, 2025
@Kivooeo Kivooeo changed the title fixed diagnostic Tail call diagnostics to include lifetime info Aug 6, 2025
@Kivooeo Kivooeo force-pushed the fun-problem-fun-fix branch 2 times, most recently from 9260c5d to 9a9f300 Compare August 6, 2025 17:07
@rustbot rustbot added the F-explicit_tail_calls `#![feature(explicit_tail_calls)]` label Aug 6, 2025
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This doesn't fix the issue in the other direction, like:

fn foo(_: fn(&())) {
    become bar(dummy);
}

fn bar<'a>(_: fn(&'a ())) {}

fn dummy(_: &()) {}

self.report_arguments_mismatch(expr.span, caller_sig, callee_sig);
self.report_arguments_mismatch(
expr.span,
self.caller_ty.fn_sig(self.tcx).skip_binder(),
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Suggested change
self.caller_ty.fn_sig(self.tcx).skip_binder(),
self.caller_ty.fn_sig(self.tcx).instantiate_identity(),

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It does not work for me

error[E0599]: no method named `instantiate_identity` found for struct `Binder` in the current scope
   --> compiler/rustc_mir_build/src/check_tail_calls.rs:137:53
    |
137 |                     self.caller_ty.fn_sig(self.tcx).instantiate_identity(),
    |                                                     ^^^^^^^^^^^^^^^^^^^^ method not found in `Binder<TyCtxt<'_>, FnSig<TyCtxt<'_>>>`

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oh, it's a binder, not an early binder. that should be liberated then probably, use tcx.liberate_late_bound_regions instead.

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I'd love to hear why current approach is not best just to learn things

Also about 'static yes it shows, should I include this in test?

4 |     become bar(dummy);
  |     ^^^^^^^^^^^^^^^^^
  |
  = note: -Ztrack-diagnostics: created at compiler/rustc_mir_build/src/check_tail_calls.rs:368:14
  = note: `become` requires caller and callee to have matching signatures
  = note: caller signature: `fn(for<'a> fn(&'a ()))`
  = note: callee signature: `fn(fn(&'static ()))`

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I did tcx.liberate_late_bound_regions it works but I did not found a better way to obtain DefId rather than do this

Update TailCallCkVisitor with adding a field that will contain def id

struct TailCallCkVisitor<'a, 'tcx> {
    ... // existed fields
    def: DefId,
}

And create it like this

    let mut visitor = TailCallCkVisitor {
        ... // eixsted fields
        def: def.to_def_id(),
    };

This might be a bad solution to pass DefId like this?

    self.report_arguments_mismatch(
        expr.span,
        self.tcx.liberate_late_bound_regions(self.def, self.caller_ty.fn_sig(self.tcx)),
        self.tcx.liberate_late_bound_regions(self.def, ty.fn_sig(self.tcx)),
    );

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Hey @compiler-errors, when you have a moment, could you take another look and let me know which approach you think works better?

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It doesn't actually matter what def id you pass. Can you just pass CRATE_DEF_ID for now?

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yeah, CRATE_DEF_ID works, didn't knew about this one

@Kivooeo Kivooeo force-pushed the fun-problem-fun-fix branch from 9a9f300 to b2997d5 Compare August 6, 2025 18:08
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Kivooeo commented Aug 6, 2025

I fixed other direction, and make test description lesser (not want to shrink it to one liner tho)

If we have a better way to do so, I'm open for suggestions because it's literally first time me opening anything related to tail call

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You should probably check if this also mentions regions like 'static since those may show up in the signature.

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r? compiler-errors

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rustbot commented Aug 13, 2025

compiler-errors is not on the review rotation at the moment.
They may take a while to respond.

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@rustbot rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 14, 2025
@rust-cloud-vms rust-cloud-vms bot force-pushed the fun-problem-fun-fix branch from b2997d5 to 409125b Compare August 14, 2025 17:22
@rust-cloud-vms rust-cloud-vms bot force-pushed the fun-problem-fun-fix branch from 409125b to 51df1da Compare August 14, 2025 17:28
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Kivooeo commented Aug 14, 2025

Added 'static test and used liberate_late_bound_regions, it looks more verbose but works too, so should be fine @rustbot ready

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 14, 2025
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@bors r+ rollup

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bors commented Aug 14, 2025

📌 Commit 51df1da has been approved by compiler-errors

It is now in the queue for this repository.

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 14, 2025
Zalathar added a commit to Zalathar/rust that referenced this pull request Aug 15, 2025
…piler-errors

Tail call diagnostics to include lifetime info

Fixes rust-lang#144957

r? `@WaffleLapkin` `@compiler-errors`
bors added a commit that referenced this pull request Aug 15, 2025
Rollup of 22 pull requests

Successful merges:

 - #118087 (Add Ref/RefMut try_map method)
 - #122661 (Change the desugaring of `assert!` for better error output)
 - #140740 (Add `-Zindirect-branch-cs-prefix`)
 - #142640 (Implement autodiff using intrinsics)
 - #143075 (compiler: Allow `extern "interrupt" fn() -> !`)
 - #144865 (Fix tail calls to `#[track_caller]` functions)
 - #144944 (E0793: Clarify that it applies to unions as well)
 - #144947 (Fix description of unsigned `checked_exact_div`)
 - #145004 (Couple of minor cleanups)
 - #145005 (strip prefix of temporary file names when it exceeds filesystem name length limit)
 - #145012 (Tail call diagnostics to include lifetime info)
 - #145065 (resolve: Introduce `RibKind::Block`)
 - #145120 (llvm: Accept new LLVM lifetime format)
 - #145189 (Weekly `cargo update`)
 - #145235 (Minor `[const]` tweaks)
 - #145275 (fix(compiler/rustc_codegen_llvm): apply `target-cpu` attribute)
 - #145322 (Resolve the prelude import in `build_reduced_graph`)
 - #145331 (Make std use the edition 2024 prelude)
 - #145369 (Do not ICE on private type in field of unresolved struct)
 - #145378 (Add `FnContext` in parser for diagnostic)
 - #145389 ([rustdoc] Revert "rustdoc search: prefer stable items in search results")
 - #145392 (coverage: Remove intermediate data structures from mapping creation)

r? `@ghost`
`@rustbot` modify labels: rollup
Zalathar added a commit to Zalathar/rust that referenced this pull request Aug 15, 2025
…piler-errors

Tail call diagnostics to include lifetime info

Fixes rust-lang#144957

r? ``@WaffleLapkin`` ``@compiler-errors``
bors added a commit that referenced this pull request Aug 15, 2025
Rollup of 21 pull requests

Successful merges:

 - #118087 (Add Ref/RefMut try_map method)
 - #122661 (Change the desugaring of `assert!` for better error output)
 - #142640 (Implement autodiff using intrinsics)
 - #143075 (compiler: Allow `extern "interrupt" fn() -> !`)
 - #144865 (Fix tail calls to `#[track_caller]` functions)
 - #144944 (E0793: Clarify that it applies to unions as well)
 - #144947 (Fix description of unsigned `checked_exact_div`)
 - #145004 (Couple of minor cleanups)
 - #145005 (strip prefix of temporary file names when it exceeds filesystem name length limit)
 - #145012 (Tail call diagnostics to include lifetime info)
 - #145065 (resolve: Introduce `RibKind::Block`)
 - #145120 (llvm: Accept new LLVM lifetime format)
 - #145189 (Weekly `cargo update`)
 - #145235 (Minor `[const]` tweaks)
 - #145275 (fix(compiler/rustc_codegen_llvm): apply `target-cpu` attribute)
 - #145322 (Resolve the prelude import in `build_reduced_graph`)
 - #145331 (Make std use the edition 2024 prelude)
 - #145369 (Do not ICE on private type in field of unresolved struct)
 - #145378 (Add `FnContext` in parser for diagnostic)
 - #145389 ([rustdoc] Revert "rustdoc search: prefer stable items in search results")
 - #145392 (coverage: Remove intermediate data structures from mapping creation)

r? `@ghost`
`@rustbot` modify labels: rollup
@bors bors merged commit 711034f into rust-lang:master Aug 15, 2025
10 checks passed
@rustbot rustbot added this to the 1.91.0 milestone Aug 15, 2025
rust-timer added a commit that referenced this pull request Aug 15, 2025
Rollup merge of #145012 - Kivooeo:fun-problem-fun-fix, r=compiler-errors

Tail call diagnostics to include lifetime info

Fixes #144957

r? ```@WaffleLapkin``` ```@compiler-errors```
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tail call diagnostics omit lifetimes
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