Skip to content

Fix trait method resolution on an adjusted never type#156047

Open
JonathanBrouwer wants to merge 2 commits intorust-lang:mainfrom
JonathanBrouwer:never-ty-method
Open

Fix trait method resolution on an adjusted never type#156047
JonathanBrouwer wants to merge 2 commits intorust-lang:mainfrom
JonathanBrouwer:never-ty-method

Conversation

@JonathanBrouwer
Copy link
Copy Markdown
Contributor

@JonathanBrouwer JonathanBrouwer commented May 1, 2026

@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 May 1, 2026
@rustbot
Copy link
Copy Markdown
Collaborator

rustbot commented May 1, 2026

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

JonathanBrouwer
JonathanBrouwer commented May 1, 2026
View reviewed changes
Comment thread tests/ui/never_type/basic/clone-never.rs
Copy link
Copy Markdown
Contributor Author

@JonathanBrouwer JonathanBrouwer May 1, 2026 •
edited by rustbot
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Note that this PR allows more code to compile on stable, for example see this test.

View changes since the review

Copy link
Copy Markdown
Contributor Author

@JonathanBrouwer JonathanBrouwer May 3, 2026 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

If this is a problem we could delay the problem by putting this change behind the never_type feature gate

lcnr
lcnr reviewed May 1, 2026
View reviewed changes
Comment thread compiler/rustc_hir_typeck/src/method/probe.rs Outdated
lcnr
lcnr reviewed May 1, 2026
View reviewed changes
Copy link
Copy Markdown
Contributor

@lcnr lcnr left a comment •
edited by rustbot
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think this a reasonable change, I would expect us to emit a FCW here, I don't want to support this permanently or more importantly, this may overlap with other kinds of inference fallback in the future, so we generally don't want users to rely on this

View changes since this review

@WaffleLapkin WaffleLapkin added the F-never_type `#![feature(never_type)]` label May 1, 2026
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@WaffleLapkin WaffleLapkin added needs-fcp This change is insta-stable, or significant enough to need a team FCP to proceed. T-types Relevant to the types team, which will review and decide on the PR/issue. labels May 1, 2026
@JonathanBrouwer
Copy link
Copy Markdown
Contributor Author

JonathanBrouwer commented May 1, 2026 •
edited
Loading

This PR is now based on #156048, still need to add the FCW lint, I'll do that later.
@rustbot author

Is "Trait method call on adjusted never type" the correct terminology? I'm not super familiar with the type system yet

@JonathanBrouwer JonathanBrouwer mentioned this pull request May 2, 2026
Merged
@rustbot rustbot removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 2, 2026
@rustbot
Copy link
Copy Markdown
Collaborator

rustbot commented May 2, 2026

Reminder, once the PR becomes ready for a review, use @rustbot ready.

@rustbot rustbot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label May 2, 2026
@rust-bors

This comment has been minimized.

Sign in to view
@rustbot
Copy link
Copy Markdown
Collaborator

rustbot commented May 3, 2026

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

JonathanBrouwer
JonathanBrouwer commented May 3, 2026
View reviewed changes
Comment thread compiler/rustc_lint_defs/src/builtin.rs
}

declare_lint! {
/// The `trait_method_on_coerced_never_type` lint detects situations in which a never type, which
Copy link
Copy Markdown
Contributor Author

@JonathanBrouwer JonathanBrouwer May 3, 2026 •
edited by rustbot
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm really unsure of what the correct terminology is, both for the lint definition and the diagnostic, so please give feedback on this

View changes since the review

JonathanBrouwer
JonathanBrouwer commented May 3, 2026
View reviewed changes
Comment thread compiler/rustc_lint_defs/src/builtin.rs
"detects trait method calls on an coerced never type",
@future_incompatible = FutureIncompatibleInfo {
reason: fcw!(FutureReleaseError #156047),
report_in_deps: true,
Copy link
Copy Markdown
Contributor Author

@JonathanBrouwer JonathanBrouwer May 3, 2026 •
edited by rustbot
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I decided on a lint with level Warn with report_in_deps: true. If something else is desired, let me know

View changes since the review

@JonathanBrouwer
Copy link
Copy Markdown
Contributor Author

JonathanBrouwer commented May 3, 2026 •
edited
Loading

@rustbot ready

I rebased on #156079 and #156048 so the diff is nicely small now

@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 May 3, 2026
@rust-log-analyzer

This comment has been minimized.

Sign in to view
@rust-log-analyzer

This comment has been minimized.

Sign in to view
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@lcnr lcnr lcnr left review comments

At least 1 approving review is required to merge this pull request.

Assignees

@lcnr lcnr

@WaffleLapkin WaffleLapkin

Labels

F-never_type `#![feature(never_type)]` needs-fcp This change is insta-stable, or significant enough to need a team FCP to proceed. 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. T-types Relevant to the types team, which will review and decide on the PR/issue.

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

Inconsistent method lookup on never type

5 participants

@JonathanBrouwer @rustbot @rust-log-analyzer @lcnr @WaffleLapkin