Remove duplicate error about raw underscore lifetime #143280

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xizheyin wants to merge 2 commits into rust-lang:master from xizheyin:143152-1

+30 −1

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xizheyin commented Jul 1, 2025 •

edited by rustbot

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Can you instead use tcx.sess.psess.raw_identifier_spans to look for the raw lifetime span? I think we populate raw_identifier_spans with raw lifetimes too.

If not, then I don't think this hack should land. Using span_to_snippet here seems fragile.

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compiler-errors commented Jul 1, 2025

r? compiler-errors

rustbot assigned compiler-errors and unassigned fee1-dead

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xizheyin commented Jul 1, 2025

Can you instead use tcx.sess.psess.raw_identifier_spans to look for the raw lifetime span? I think we populate raw_identifier_spans with raw lifetimes too.

I have a try on it, and it works.

xizheyin force-pushed the 143152-1 branch from 27d05c0 to edd5a3e Compare

July 1, 2025 16:56

xizheyin commented

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compiler/rustc_resolve/src/late.rs Outdated

Comment on lines 2905 to 2914

+                              // To avoid emitting two duplicate errors, we need to check if the span is a raw underscore lifetime, see issue #143152
+                              let is_raw_underscore = self
+                                  .r
+                                  .tcx
+                                  .sess
+                                  .psess
+                                  .raw_identifier_spans
+                                  .iter()
+                                  .any(|span| span == param.span());
+                              if param.ident.name == kw::UnderscoreLifetime && !is_raw_underscore {

Contributor Author

xizheyin Jul 1, 2025

I'm wondering if I should split it into 2 parts, as this doesn't seem very aesthetically pleasing taking up so many lines. However it seems to give the wrong impression that the variable in the middle will be used multiple times.

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xizheyin force-pushed the 143152-1 branch from edd5a3e to efc35e8 Compare

July 5, 2025 09:32

xizheyin commented

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xizheyin left a comment •

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We may not be able to use emit_unless, because there are other logic in the if block.

                if param.ident.name == kw::UnderscoreLifetime && !is_raw_underscore {
                    self.r
                        .dcx()
                        .emit_err(errors::UnderscoreLifetimeIsReserved { span: param.ident.span });
                    // Record lifetime res, so lowering knows there is something fishy.
                    self.record_lifetime_param(param.id, LifetimeRes::Error);
                    continue;
                }

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We may not be able to use emit_unless, because there are other logic in the if block.

Did you try it?

Just try calling self.record_lifetime_param(param.id, LifetimeRes::Error); unconditionally, it should be fine. We should definitely be delaying a bug.

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xizheyin force-pushed the 143152-1 branch from efc35e8 to 3af14f3 Compare

July 17, 2025 16:25

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xizheyin added 2 commits

July 18, 2025 00:28


          Add test raw-underscore-lifetime.rs

cecf9ea

Signed-off-by: xizheyin <[email protected]>


          Remove similar errors about raw underscore lifetime

848d4a5

Signed-off-by: xizheyin <[email protected]>

xizheyin force-pushed the 143152-1 branch from 3af14f3 to 848d4a5 Compare

July 17, 2025 16:36

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xizheyin left a comment

By the way, emit_unless doesn't seem intuitive and is very misleading, is it possible to give it a new name, e.g. emit_or_delay_as_bug

compiler/rustc_resolve/src/late.rs

Comment on lines 2914 to +2916

    
                                      .dcx()

                                      .emit_err(errors::UnderscoreLifetimeIsReserved { span: param.ident.span });

                                      .create_err(errors::UnderscoreLifetimeIsReserved { span: param.ident.span })

                                      .emit_unless(is_raw_underscore_lifetime);

Contributor Author

xizheyin Jul 17, 2025

Oh my bad, the code now doesn't affect the original logic.

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compiler-errors commented Jul 17, 2025

@bors r+ rollup

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bors commented Jul 17, 2025

📌 Commit 848d4a5 has been approved by compiler-errors

It is now in the queue for this repository.

bors added S-waiting-on-bors and removed S-waiting-on-review labels

jhpratt added a commit to jhpratt/rust that referenced this pull request


          Rollup merge of rust-lang#143280 - xizheyin:143152-1, r=compiler-errors

e62471d

Remove duplicate error about raw underscore lifetime

Fixes rust-lang#143152

r? `@fee1-dead`

jhpratt mentioned this pull request

Rollup of 12 pull requests #144101

Closed

bors added a commit that referenced this pull request


          Auto merge of #144101 - jhpratt:rollup-zkqhgwt, r=jhpratt

30f3706

Rollup of 12 pull requests

Successful merges:

 - #142300 (Disable `tests/run-make/mte-ffi` because no CI runners have MTE extensions enabled)
 - #143271 (Store the type of each GVN value)
 - #143280 (Remove duplicate error about raw underscore lifetime)
 - #143649 (Add test for `default_field_values` and `const_default`)
 - #143699 (Make `AsyncDrop` check that it's being implemented on a local ADT)
 - #143719 (Emit warning when there is no space between `-o` and arg)
 - #143833 (Ban projecting into SIMD types [MCP838])
 - #143891 (Port `#[coverage]` to the new attribute system)
 - #143908 (`tests/ui`: A New Order [0/28] )
 - #143909 (docs(alloc::fmt): Make type optional, instead of matching empty string)
 - #143925 (Make slice comparisons const)
 - #143997 (Use $crate in macros for rustc_public (aka stable_mir))

r? `@ghost`
`@rustbot` modify labels: rollup

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request


          Rollup merge of rust-lang#143280 - xizheyin:143152-1, r=compiler-errors

949a8b9

Remove duplicate error about raw underscore lifetime

Fixes rust-lang#143152

r? ``@fee1-dead``

matthiaskrgr mentioned this pull request

Rollup of 12 pull requests #144110

Open

bors added a commit that referenced this pull request


          Auto merge of #144110 - matthiaskrgr:rollup-y8g1bpr, r=matthiaskrgr

68f07e3

Rollup of 12 pull requests

Successful merges:

 - #143280 (Remove duplicate error about raw underscore lifetime)
 - #143649 (Add test for `default_field_values` and `const_default`)
 - #143699 (Make `AsyncDrop` check that it's being implemented on a local ADT)
 - #143704 (Be a bit more careful around exotic cycles in in the inliner)
 - #143908 (`tests/ui`: A New Order [0/28] )
 - #143909 (docs(alloc::fmt): Make type optional, instead of matching empty string)
 - #143925 (Make slice comparisons const)
 - #143997 (Use $crate in macros for rustc_public (aka stable_mir))
 - #144013 (resolve: Make disambiguators for underscore bindings module-local)
 - #144029 (Fix wrong messages from methods with the same name from different traits)
 - #144063 (Add myself to the `infra-ci` reviewer group and adjust some infra auto-labels)
 - #144069 (ci: use windows 22 for all free runners)

r? `@ghost`
`@rustbot` modify labels: rollup

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