Account for ownership mismatch on argument that doesn't meet bound by estebank · Pull Request #153749 · rust-lang/rust

estebank · 2026-03-11T23:37:36Z

error[E0277]: the trait bound `needs_borrow::Hello: needs_borrow::Tr` is not satisfied
  --> $DIR/ownership-mismatch-on-arg.rs:42:13
   |
LL |             foo(hi, hi, hi);
   |             ^^^ --  -- `needs_borrow::Hello` doesn't satisfy the trait bound
   |             |   |
   |             |   `needs_borrow::Hello` doesn't satisfy the trait bound
   |             unsatisfied trait bound
   |
help: the trait `needs_borrow::Tr` is not implemented for `needs_borrow::Hello`
  --> $DIR/ownership-mismatch-on-arg.rs:27:5
   |
LL |     struct Hello;
   |     ^^^^^^^^^^^^
help: the trait `needs_borrow::Tr` is implemented for `&needs_borrow::Hello`
  --> $DIR/ownership-mismatch-on-arg.rs:30:5
   |
LL |     impl Tr for &Hello {}
   |     ^^^^^^^^^^^^^^^^^^
note: required by a bound in `needs_borrow::foo`
  --> $DIR/ownership-mismatch-on-arg.rs:32:15
   |
LL |     fn foo<T: Tr, K: std::fmt::Debug>(_v: T, _w: T, _k: K) {}
   |               ^^ required by this bound in `foo`
help: consider borrowing these argument
   |
LL |             foo(&hi, &hi, hi);
   |                 +    +

Fix #134805.

rustbot · 2026-03-11T23:37:41Z

r? @JonathanBrouwer

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estebank · 2026-03-11T23:40:23Z

+mod needs_deref {
+    #[derive(Clone, Copy, Debug)]
+    struct Hello;
+
+    trait Tr: Clone + Copy {}
+    impl Tr for Hello {}
+
+    fn foo<T: Tr, K: std::fmt::Debug>(_v: T, _w: T, _k: K) {}
+
+    struct S;
+    impl S {
+        fn foo<K: std::fmt::Debug, T: Tr>(&self, _v: T, _w: T, _k: K) {}
+    }
+
+    fn bar() {
+        let hellos = [Hello; 3];
+        for hi in hellos.iter() {
+            foo(hi, hi, hi); //~ ERROR: the trait bound `&needs_deref::Hello: needs_deref::Tr` is not satisfied
+            S.foo(hi, hi, hi); //~ ERROR: the trait bound `&needs_deref::Hello: needs_deref::Tr` is not satisfied
+        }
+    }
+}


@arferreira This case I was mentioning that would be nice to handle after this PR (plus one other test for Hello not being Copy but still being Clone) is what still needs to be handled. We should suggest

foo(*hi, *hi, hi); S.foo(*hi, *hi, hi);

for the case above and

foo(hi.clone(), hi.clone(), hi); S.foo(hi.clone(), hi.clone(), hi);

if possible.

Sounds good, I'll pick up that. Thanks for the context!

JonathanBrouwer · 2026-03-12T12:15:17Z

r? types

lcnr · 2026-03-30T11:48:11Z

sry for not getting to this for so long, currently cleaning up my notification backlog

r? types

jackh726

I'd be okay to land as-is, but have some minor comments.

View changes since this review

jackh726 · 2026-03-30T19:24:10Z

                }
                c
            }
+            ObligationCauseCode::WhereClauseInExpr(def_id, _, hir_id, idx)


A lot of this code is duplicated...any way to deduplicate?

Sorry for the delay. I tried moving some of the suggestion logic to a closure, but there's some duplication in the pattern decomposition.

``` error[E0277]: the trait bound `needs_borrow::Hello: needs_borrow::Tr` is not satisfied --> $DIR/ownership-mismatch-on-arg.rs:42:13 | LL | foo(hi, hi, hi); | ^^^ -- -- `needs_borrow::Hello` doesn't satisfy the trait bound | | | | | `needs_borrow::Hello` doesn't satisfy the trait bound | unsatisfied trait bound | help: the trait `needs_borrow::Tr` is not implemented for `needs_borrow::Hello` --> $DIR/ownership-mismatch-on-arg.rs:27:5 | LL | struct Hello; | ^^^^^^^^^^^^ help: the trait `needs_borrow::Tr` is implemented for `&needs_borrow::Hello` --> $DIR/ownership-mismatch-on-arg.rs:30:5 | LL | impl Tr for &Hello {} | ^^^^^^^^^^^^^^^^^^ note: required by a bound in `needs_borrow::foo` --> $DIR/ownership-mismatch-on-arg.rs:32:15 | LL | fn foo<T: Tr, K: std::fmt::Debug>(_v: T, _w: T, _k: K) {} | ^^ required by this bound in `foo` help: consider borrowing these argument | LL | foo(&hi, &hi, hi); | + + ```

rustbot · 2026-07-29T09:14:52Z

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.

jackh726 · 2026-08-03T16:10:37Z

@bors r+

rust-bors · 2026-08-03T16:10:40Z

📌 Commit 1e1a699 has been approved by jackh726

It is now in the queue for this repository.

Account for ownership mismatch on argument that doesn't meet bound ``` error[E0277]: the trait bound `needs_borrow::Hello: needs_borrow::Tr` is not satisfied --> $DIR/ownership-mismatch-on-arg.rs:42:13 | LL | foo(hi, hi, hi); | ^^^ -- -- `needs_borrow::Hello` doesn't satisfy the trait bound | | | | | `needs_borrow::Hello` doesn't satisfy the trait bound | unsatisfied trait bound | help: the trait `needs_borrow::Tr` is not implemented for `needs_borrow::Hello` --> $DIR/ownership-mismatch-on-arg.rs:27:5 | LL | struct Hello; | ^^^^^^^^^^^^ help: the trait `needs_borrow::Tr` is implemented for `&needs_borrow::Hello` --> $DIR/ownership-mismatch-on-arg.rs:30:5 | LL | impl Tr for &Hello {} | ^^^^^^^^^^^^^^^^^^ note: required by a bound in `needs_borrow::foo` --> $DIR/ownership-mismatch-on-arg.rs:32:15 | LL | fn foo<T: Tr, K: std::fmt::Debug>(_v: T, _w: T, _k: K) {} | ^^ required by this bound in `foo` help: consider borrowing these argument | LL | foo(&hi, &hi, hi); | + + ``` Fix rust-lang#134805.

…uwer Rollup of 23 pull requests Successful merges: - #153749 (Account for ownership mismatch on argument that doesn't meet bound) - #159326 (Deny multiple EII impls on a single item) - #159535 (Optimize slice::contains for bytewise types) - #159595 (Promote loongarch32-unknown-none* to Tier 2) - #160007 (allow `-Ldependency` search paths for panic runtimes) - #160184 (Add -Zinstrument-mcount={fentry-nop-record,fentry-record}) - #160320 (point at trait definition when it is used as a derive macro) - #160369 (When suggesting method names, prefer *exact* doc aliases over similar names) - #160406 (`DepKind` cleanups) - #160424 (Use `thread::available_parallelism` as the default limit for backend parallelism) - #159303 (Fix ICE for direct inline const generic defaults) - #159977 (Add regression test for bool indexing codegen) - #160011 (remove InterpError::map_err_info) - #160165 (reject `...` without pattern post-expansion) - #160295 (Fix rustdoc ICE when checking if a generic arg can be elided) - #160305 (Linkify C-SKY targets in `platform-support.md`) - #160314 (fix borrowck ICE for consts with fn pointer type) - #160322 (ElaborateBoxDeref: remove unnecessary projection) - #160338 (Add regression test for supertrait associated type normalization through dyn) - #160340 (Add regression test for unused_parens on contract clauses) - #160371 (Add doc aliases for transpositions `read_exact_buf` and `read_exact_buf_at`) - #160384 (Add PR body notes for Cargo lock file maintenance) - #160435 (bump tracing-tree)

Account for ownership mismatch on argument that doesn't meet bound ``` error[E0277]: the trait bound `needs_borrow::Hello: needs_borrow::Tr` is not satisfied --> $DIR/ownership-mismatch-on-arg.rs:42:13 | LL | foo(hi, hi, hi); | ^^^ -- -- `needs_borrow::Hello` doesn't satisfy the trait bound | | | | | `needs_borrow::Hello` doesn't satisfy the trait bound | unsatisfied trait bound | help: the trait `needs_borrow::Tr` is not implemented for `needs_borrow::Hello` --> $DIR/ownership-mismatch-on-arg.rs:27:5 | LL | struct Hello; | ^^^^^^^^^^^^ help: the trait `needs_borrow::Tr` is implemented for `&needs_borrow::Hello` --> $DIR/ownership-mismatch-on-arg.rs:30:5 | LL | impl Tr for &Hello {} | ^^^^^^^^^^^^^^^^^^ note: required by a bound in `needs_borrow::foo` --> $DIR/ownership-mismatch-on-arg.rs:32:15 | LL | fn foo<T: Tr, K: std::fmt::Debug>(_v: T, _w: T, _k: K) {} | ^^ required by this bound in `foo` help: consider borrowing these argument | LL | foo(&hi, &hi, hi); | + + ``` Fix rust-lang#134805.

…uwer Rollup of 26 pull requests Successful merges: - #153749 (Account for ownership mismatch on argument that doesn't meet bound) - #158727 (std: use `readdir` on nearly all UNIX platforms) - #159130 (a bit optimize four-digit chunks in integer formatting) - #159326 (Deny multiple EII impls on a single item) - #159535 (Optimize slice::contains for bytewise types) - #159595 (Promote loongarch32-unknown-none* to Tier 2) - #160184 (Add -Zinstrument-mcount={fentry-nop-record,fentry-record}) - #160320 (point at trait definition when it is used as a derive macro) - #160369 (When suggesting method names, prefer *exact* doc aliases over similar names) - #160406 (`DepKind` cleanups) - #160424 (Use `thread::available_parallelism` as the default limit for backend parallelism) - #159303 (Fix ICE for direct inline const generic defaults) - #159977 (Add regression test for bool indexing codegen) - #160011 (remove InterpError::map_err_info) - #160165 (reject `...` without pattern post-expansion) - #160295 (Fix rustdoc ICE when checking if a generic arg can be elided) - #160305 (Linkify C-SKY targets in `platform-support.md`) - #160314 (fix borrowck ICE for consts with fn pointer type) - #160322 (ElaborateBoxDeref: remove unnecessary projection) - #160338 (Add regression test for supertrait associated type normalization through dyn) - #160340 (Add regression test for unused_parens on contract clauses) - #160371 (Add doc aliases for transpositions `read_exact_buf` and `read_exact_buf_at`) - #160384 (Add PR body notes for Cargo lock file maintenance) - #160412 (Move duplicate-names check for #[rustc_must_implement_one_of] to attribute parser) - #160435 (bump tracing-tree) - #160449 (Fix lookup of object files)

rustbot assigned JonathanBrouwer Mar 11, 2026

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 Mar 11, 2026

estebank commented Mar 11, 2026

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estebank force-pushed the issue-134805 branch from d697693 to 9f64596 Compare March 11, 2026 23:44

rustbot added the T-types Relevant to the types team, which will review and decide on the PR/issue. label Mar 12, 2026

rustbot assigned lcnr and unassigned JonathanBrouwer Mar 12, 2026

rustbot assigned jackh726 and unassigned lcnr Mar 30, 2026

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estebank force-pushed the issue-134805 branch from 9f64596 to 6251629 Compare July 29, 2026 08:48

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estebank added 2 commits July 29, 2026 09:08

deduplicate method/function call "point at arg" logic

1e1a699

estebank force-pushed the issue-134805 branch from 6251629 to 1e1a699 Compare July 29, 2026 09:14

rust-bors Bot 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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Aug 3, 2026

JonathanBrouwer mentioned this pull request Aug 3, 2026

Rollup of 23 pull requests #160455

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JonathanBrouwer mentioned this pull request Aug 3, 2026

Rollup of 26 pull requests #160469

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