diagnostics: avoid ICE for undeclared generic parameter in impl#154182

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Unique-Usman wants to merge 1 commit intorust-lang:mainfrom

Unique-Usman:ua/constnotype2

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Unique-Usman commented Mar 21, 2026 •

edited by rustbot

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Avoid an ICE for:

struct A;
impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds tests/ui/missing/undeclared-generic-parameter.rs.

Fixes #154165 and introduced by #152913

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Unique-Usman force-pushed the ua/constnotype2 branch from b88bcb8 to 20d63f9 Compare

March 21, 2026 16:23

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          diagnostics: avoid ICE for undeclared generic parameter in impl

b31dc4a

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Signed-off-by: Usman Akinyemi <usmanakinyemi202@gmail.com>

Unique-Usman force-pushed the ua/constnotype2 branch from 20d63f9 to b31dc4a Compare

March 21, 2026 16:25

Unique-Usman changed the title ~~diagnostics: ICE for undeclared generic parameter in impl~~ diagnostics: avoid ICE for undeclared generic parameter in impl

Unique-Usman mentioned this pull request

[ICE]: diagnostics: index out of bounds let target_param = &struct_generics.params[idx] #154165

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Unique-Usman commented Mar 21, 2026 •

edited

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r? @matthiaskrgr

rustbot assigned matthiaskrgr and unassigned petrochenkov

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Kivooeo commented Mar 21, 2026

Please, don't assign Matthias

r? compiler

rustbot assigned jieyouxu and unassigned matthiaskrgr

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estebank commented Mar 21, 2026

@bors r+ rollup

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rust-bors bot commented Mar 21, 2026

📌 Commit b31dc4a has been approved by estebank

It is now in the queue for this repository.

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

estebank reviewed

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tests/ui/missing/undeclared-generic-parameter.stderr

Comment on lines +1 to +17

    
              error[E0425]: cannot find type `B` in this scope

                --> $DIR/undeclared-generic-parameter.rs:2:8

                 |

              LL | struct A;

                 | --------- similarly named struct `A` defined here

              LL | impl A<B> {}

                 |        ^

                 |

              help: a struct with a similar name exists

                 |

              LL - impl A<B> {}

              LL + impl A<A> {}

                 |

              help: you might be missing a type parameter

                 |

              LL | impl<B> A<B> {}

                 |     +++

Contributor

estebank Mar 21, 2026 •

edited

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(Not for this PR) It'd be nice if we didn't provide any suggestion in this case and instead mentioned that A takes no parameter (at this place, same thing for struct A<T> and impl<T> A<T, K> {} so that we emit a single error instead of two, but this is [p-low].

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

afa0eef

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

JonathanBrouwer mentioned this pull request

Rollup of 4 pull requests #154186

Closed

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

d088150

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

JonathanBrouwer mentioned this pull request

Rollup of 3 pull requests #154187

Closed

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

c3f5200

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

JonathanBrouwer mentioned this pull request

Rollup of 7 pull requests #154192

Closed

rust-bors bot pushed a commit that referenced this pull request


          Auto merge of #154192 - JonathanBrouwer:rollup-TkGjSDo, r=JonathanBro…

1cd6ddd

…uwer

Rollup of 7 pull requests

Successful merges:

 - #122668 (Add APIs for dealing with titlecase)
 - #153312 (Packages as namespaces part 1)
 - #153534 (Remove a flaky `got_timeout` assert from two channel tests)
 - #154094 (add neon load/store assembly test)
 - #154175 (Add new alias for Guillaume Gomez email address)
 - #154182 (diagnostics: avoid ICE for undeclared generic parameter in impl)
 - #154188 (Update the tracking issue for #[diagnostic::on_move])

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

473d823

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

Zalathar mentioned this pull request

Rollup of 6 pull requests #154198

Closed

rust-bors bot pushed a commit that referenced this pull request


          Auto merge of #154198 - Zalathar:rollup-09a81nY, r=Zalathar

0ed4005

Rollup of 6 pull requests

Successful merges:

 - #122668 (Add APIs for dealing with titlecase)
 - #153312 (Packages as namespaces part 1)
 - #153534 (Remove a flaky `got_timeout` assert from two channel tests)
 - #154175 (Add new alias for Guillaume Gomez email address)
 - #154182 (diagnostics: avoid ICE for undeclared generic parameter in impl)
 - #154188 (Update the tracking issue for #[diagnostic::on_move])

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

72cf504

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

Zalathar mentioned this pull request

Rollup of 7 pull requests #154203

Closed

rust-bors bot pushed a commit that referenced this pull request


          Auto merge of #154203 - Zalathar:rollup-tqV88T3, r=Zalathar

fc14dc6

Rollup of 7 pull requests

Successful merges:

 - #122668 (Add APIs for dealing with titlecase)
 - #153312 (Packages as namespaces part 1)
 - #153534 (Remove a flaky `got_timeout` assert from two channel tests)
 - #154175 (Add new alias for Guillaume Gomez email address)
 - #154182 (diagnostics: avoid ICE for undeclared generic parameter in impl)
 - #154188 (Update the tracking issue for #[diagnostic::on_move])
 - #154201 (Use enums to clarify `DepNodeColorMap` color marking )

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

b7b5bd1

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

Zalathar mentioned this pull request

Rollup of 9 pull requests #154208

Closed

rust-bors bot pushed a commit that referenced this pull request


          Auto merge of #154208 - Zalathar:rollup-7KSCNHC, r=Zalathar

091254f

Rollup of 9 pull requests

Successful merges:

 - #122668 (Add APIs for dealing with titlecase)
 - #153312 (Packages as namespaces part 1)
 - #153534 (Remove a flaky `got_timeout` assert from two channel tests)
 - #153582 (Simplify find_attr! for HirId usage)
 - #154174 (allow `incomplete_features` in most UI tests)
 - #154175 (Add new alias for Guillaume Gomez email address)
 - #154182 (diagnostics: avoid ICE for undeclared generic parameter in impl)
 - #154188 (Update the tracking issue for #[diagnostic::on_move])
 - #154201 (Use enums to clarify `DepNodeColorMap` color marking )

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

f51c744

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

JonathanBrouwer mentioned this pull request

Rollup of 13 pull requests #154219

Closed

Contributor

JonathanBrouwer commented Mar 22, 2026

@bors try jobs=x86_64-gnu-aux
Seeing if the hang in this job is maybe real, since it happened 3 times in a row

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rust-bors bot pushed a commit that referenced this pull request


          Auto merge of #154182 - Unique-Usman:ua/constnotype2, r=<try>

2e70e9a

diagnostics: avoid ICE for undeclared generic parameter in impl


try-job: x86_64-gnu-aux

Contributor

rust-bors bot commented Mar 22, 2026

☀️ Try build successful (CI)
Build commit: 2e70e9a (2e70e9a192e49ab70972cecb316ae79a7487f6e1, parent: 562dee4820c458d823175268e41601d4c060588a)

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

c9b2683

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

JonathanBrouwer mentioned this pull request

Rollup of 23 pull requests #154226

Closed

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


          Rollup merge of rust-lang#154182 - Unique-Usman:ua/constnotype2, r=es…

3eaa73c

…tebank

diagnostics: avoid ICE for undeclared generic parameter in impl

Avoid an ICE for:

    struct A;
    impl A<B> {}

The compiler no longer panics and can proceed to emit existing diagnostics.

Adds `tests/ui/missing/undeclared-generic-parameter.rs`.

Fixes rust-lang#154165 and introduced by rust-lang#152913

JonathanBrouwer mentioned this pull request

Rollup of 22 pull requests #154227

Open

rust-bors bot pushed a commit that referenced this pull request


          Auto merge of #154227 - JonathanBrouwer:rollup-Y3AkxdT, r=JonathanBro…

14b8819

…uwer

Rollup of 22 pull requests

Successful merges:

 - #122668 (Add APIs for dealing with titlecase)
 - #152543 (privacy: Fix type privacy holes in RPITITs)
 - #153107 (Optimize BTreeMap::append() using CursorMut)
 - #153312 (Packages as namespaces part 1)
 - #153534 (Remove a flaky `got_timeout` assert from two channel tests)
 - #153718 (Fix environ on FreeBSD with cdylib targets that use -Wl,--no-undefined .)
 - #153857 (Rename `target.abi` to `target.cfg_abi` and enum-ify llvm_abiname)
 - #153880 (Lifted intersperse and intersperse_with Fused transformation and updated documentation + tests)
 - #153931 (remove usages of to-be-deprecated numeric constants)
 - #150630 (Unknown -> Unsupported compression algorithm)
 - #153491 (Move `freeze_*` methods to `OpenOptionsExt2`)
 - #153582 (Simplify find_attr! for HirId usage)
 - #153623 (std: move `sys::pal::os` to `sys::paths`)
 - #153647 (docs(fs): Clarify That File::lock Coordinates Across Processes)
 - #153936 (Skip stack_start_aligned for immediate-abort)
 - #154011 (implement `BinaryHeap::as_mut_slice`)
 - #154167 (ui/lto: move and rename two tests from issues/)
 - #154174 (allow `incomplete_features` in most UI tests)
 - #154175 (Add new alias for Guillaume Gomez email address)
 - #154182 (diagnostics: avoid ICE for undeclared generic parameter in impl)
 - #154188 (Update the tracking issue for #[diagnostic::on_move])
 - #154201 (Use enums to clarify `DepNodeColorMap` color marking )

jieyouxu assigned estebank and unassigned jieyouxu

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