Suggest fully qualified path on method name collision by estebank · Pull Request #153662 · rust-lang/rust

estebank · 2026-03-10T15:51:55Z

Provide suggestion for using a fully qualified path when method names collide between traits and inherent impl.

error[E0061]: this method takes 0 arguments but 1 argument was supplied
  --> $DIR/shadowed-intrinsic-method.rs:20:7
   |
LL |     a.borrow(());
   |       ^^^^^^ -- unexpected argument of type `()`
   |
note: the `borrow` call is resolved to the method in `std::borrow::Borrow`, shadowing the method of the same name on the inherent impl for `A`
  --> $DIR/shadowed-intrinsic-method.rs:20:7
   |
LL | use std::borrow::Borrow;
   |     ------------------- `std::borrow::Borrow` imported here
...
LL |     a.borrow(());
   |       ^^^^^^ refers to `std::borrow::Borrow::borrow`
note: method defined here
  --> $SRC_DIR/core/src/borrow.rs:LL:COL
help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly
   |
LL -     a.borrow(());
LL +     A::borrow(&mut a, ());
   |
help: remove the extra argument
   |
LL -     a.borrow(());
LL +     a.borrow();
   |

Fix #54103.

rustbot · 2026-03-10T15:52:01Z

r? @davidtwco

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estebank · 2026-03-10T17:06:00Z

compiler/rustc_hir_typeck/src/demand.rs

-                        ),
-                    ),
+                let fn_sig = self.tcx.fn_sig(m.def_id);
+                if fn_sig.skip_binder().inputs().skip_binder().len() != args.len() + 1 {


We should be running this logic 3 times: one for "all of the arguments apply", "the number of arguments match" and "only the name matches", in order. If any of the cases happens, break (as we get less and less confident the further away we get from things matching).

Detect inherent method behind deref being shadowed by trait method ``` error[E0277]: the trait bound `Rc<RefCell<S>>: Borrow<S>` is not satisfied --> $DIR/shadowed-intrinsic-method-deref.rs:16:22 | LL | let sb : &S = &s.borrow(); | ^^^^^^ the trait `Borrow<S>` is not implemented for `Rc<RefCell<S>>` | help: the trait `Borrow<S>` is not implemented for `Rc<RefCell<S>>` but trait `Borrow<RefCell<S>>` is implemented for it --> $SRC_DIR/alloc/src/rc.rs:LL:COL = help: for that trait implementation, expected `RefCell<S>`, found `S` = note: there's an inherent method on `RefCell<S>` of the same name, which can be auto-dereferenced from `&RefCell<T>` help: to access the inherent method on `RefCell<S>`, use the fully-qualified path | LL - let sb : &S = &s.borrow(); LL + let sb : &S = &RefCell::borrow(&s); | ``` In the example above, method `borrow` is available both on `<RefCell<S> as Borrow<S>>` *and* on `RefCell<S>`. Adding the import `use std::borrow::Borrow;` causes `s.borrow()` to find the former instead of the latter. We now point out that the other exists, and provide a suggestion on how to call it. Fix rust-lang#41906. CC rust-lang#153662.

Detect inherent method behind deref being shadowed by trait method ``` error[E0277]: the trait bound `Rc<RefCell<S>>: Borrow<S>` is not satisfied --> $DIR/shadowed-intrinsic-method-deref.rs:16:22 | LL | let sb : &S = &s.borrow(); | ^^^^^^ the trait `Borrow<S>` is not implemented for `Rc<RefCell<S>>` | help: the trait `Borrow<S>` is not implemented for `Rc<RefCell<S>>` but trait `Borrow<RefCell<S>>` is implemented for it --> $SRC_DIR/alloc/src/rc.rs:LL:COL = help: for that trait implementation, expected `RefCell<S>`, found `S` = note: there's an inherent method on `RefCell<S>` of the same name, which can be auto-dereferenced from `&RefCell<T>` help: to access the inherent method on `RefCell<S>`, use the fully-qualified path | LL - let sb : &S = &s.borrow(); LL + let sb : &S = &RefCell::borrow(&s); | ``` In the example above, method `borrow` is available both on `<RefCell<S> as Borrow<S>>` *and* on `RefCell<S>`. Adding the import `use std::borrow::Borrow;` causes `s.borrow()` to find the former instead of the latter. We now point out that the other exists, and provide a suggestion on how to call it. Fix rust-lang/rust#41906. CC rust-lang/rust#153662.

davidtwco

LGTM

View changes since this review

davidtwco · 2026-03-25T14:07:28Z

@bors r+ rollup

rust-bors · 2026-03-25T14:07:31Z

📌 Commit 67036af has been approved by davidtwco

It is now in the queue for this repository.

…ath, r=davidtwco Suggest fully qualified path on method name collision Provide suggestion for using a fully qualified path when method names collide between traits and inherent impl. ``` error[E0061]: this method takes 0 arguments but 1 argument was supplied --> $DIR/shadowed-intrinsic-method.rs:20:7 | LL | a.borrow(()); | ^^^^^^ -- unexpected argument of type `()` | note: the `borrow` call is resolved to the method in `std::borrow::Borrow`, shadowing the method of the same name on the inherent impl for `A` --> $DIR/shadowed-intrinsic-method.rs:20:7 | LL | use std::borrow::Borrow; | ------------------- `std::borrow::Borrow` imported here ... LL | a.borrow(()); | ^^^^^^ refers to `std::borrow::Borrow::borrow` note: method defined here --> $SRC_DIR/core/src/borrow.rs:LL:COL help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly | LL - a.borrow(()); LL + A::borrow(&mut a, ()); | help: remove the extra argument | LL - a.borrow(()); LL + a.borrow(); | ``` Fix rust-lang#54103.

JonathanBrouwer · 2026-03-25T18:52:15Z

@bors r-
#154378 (comment)

rust-bors · 2026-03-25T18:52:22Z

This pull request was unapproved.

This PR was contained in a rollup (#154378), which was unapproved.

``` error[E0061]: this method takes 0 arguments but 1 argument was supplied --> $DIR/shadowed-intrinsic-method.rs:18:7 | LL | a.borrow(()); | ^^^^^^ -- unexpected argument of type `()` | note: the `borrow` call is resolved to the method in `std::borrow::Borrow`, shadowing the method of the same name on the inherent impl for `A` --> $DIR/shadowed-intrinsic-method.rs:18:7 | LL | use std::borrow::Borrow; | ------------------- `std::borrow::Borrow` imported here ... LL | a.borrow(()); | ^^^^^^ refers to `std::borrow::Borrow::borrow` note: method defined here --> $SRC_DIR/core/src/borrow.rs:LL:COL help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly | LL - a.borrow(()); LL + A::borrow(&mut a, ()); | help: remove the extra argument | LL - a.borrow(()); LL + a.borrow(); | ```

Handle correct gramar in the face of a single other option, or many.

rustbot · 2026-03-25T19:22:19Z

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.

davidtwco · 2026-03-26T15:03:33Z

@bors r+

rust-bors · 2026-03-26T15:03:37Z

📌 Commit 0bd2852 has been approved by davidtwco

It is now in the queue for this repository.

…ath, r=davidtwco Suggest fully qualified path on method name collision Provide suggestion for using a fully qualified path when method names collide between traits and inherent impl. ``` error[E0061]: this method takes 0 arguments but 1 argument was supplied --> $DIR/shadowed-intrinsic-method.rs:20:7 | LL | a.borrow(()); | ^^^^^^ -- unexpected argument of type `()` | note: the `borrow` call is resolved to the method in `std::borrow::Borrow`, shadowing the method of the same name on the inherent impl for `A` --> $DIR/shadowed-intrinsic-method.rs:20:7 | LL | use std::borrow::Borrow; | ------------------- `std::borrow::Borrow` imported here ... LL | a.borrow(()); | ^^^^^^ refers to `std::borrow::Borrow::borrow` note: method defined here --> $SRC_DIR/core/src/borrow.rs:LL:COL help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly | LL - a.borrow(()); LL + A::borrow(&mut a, ()); | help: remove the extra argument | LL - a.borrow(()); LL + a.borrow(); | ``` Fix rust-lang#54103.

Rollup of 7 pull requests Successful merges: - #152457 (Pass -pg to linker when using -Zinstrument-mcount) - #154031 (Remove divergence check from check_expr_array) - #154418 (move many tests out of `ui/unsafe`) - #153662 (Suggest fully qualified path on method name collision) - #153675 (simd_add/sub/mul/neg: document overflow behavior) - #154110 (Change "error finalizing incremental compilation" text and emit it as a note, not a warning) - #154430 (Create GPU target notification group)

…ath, r=davidtwco Suggest fully qualified path on method name collision Provide suggestion for using a fully qualified path when method names collide between traits and inherent impl. ``` error[E0061]: this method takes 0 arguments but 1 argument was supplied --> $DIR/shadowed-intrinsic-method.rs:20:7 | LL | a.borrow(()); | ^^^^^^ -- unexpected argument of type `()` | note: the `borrow` call is resolved to the method in `std::borrow::Borrow`, shadowing the method of the same name on the inherent impl for `A` --> $DIR/shadowed-intrinsic-method.rs:20:7 | LL | use std::borrow::Borrow; | ------------------- `std::borrow::Borrow` imported here ... LL | a.borrow(()); | ^^^^^^ refers to `std::borrow::Borrow::borrow` note: method defined here --> $SRC_DIR/core/src/borrow.rs:LL:COL help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly | LL - a.borrow(()); LL + A::borrow(&mut a, ()); | help: remove the extra argument | LL - a.borrow(()); LL + a.borrow(); | ``` Fix rust-lang#54103.

Rollup of 7 pull requests Successful merges: - #152457 (Pass -pg to linker when using -Zinstrument-mcount) - #154031 (Remove divergence check from check_expr_array) - #154418 (move many tests out of `ui/unsafe`) - #154441 (bootstrap: force a CI LLVM stamp bump) - #153662 (Suggest fully qualified path on method name collision) - #153675 (simd_add/sub/mul/neg: document overflow behavior) - #154430 (Create GPU target notification group)

Zalathar · 2026-03-27T06:16:44Z

Failed in rollup in test-various: Rollup of 7 pull requests #154448 (comment)

@bors r-
@bors try jobs=test-various

rust-bors · 2026-03-27T06:16:50Z

This pull request was unapproved.

This PR was contained in a rollup (#154448), which was unapproved.

Suggest fully qualified path on method name collision try-job: test-various

rust-bors · 2026-03-27T07:13:01Z

💔 Test for 7709c37 failed: CI. Failed job:

try - test-various (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-03-27T07:13:05Z

The job test-various failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

Saved the actual stderr to `/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args/diagnostic-method-lookup-returns-sig-with-fewer-args.stderr`
diff of stderr:

16    |
17 LL |     target.get(10.0); // (used to crash here)
18    |            ^^^ refers to `Target::get`
-    = note: additionally, there is 1 other available method that isn't in scope
- help: you might have meant to call one of the other methods; you can use the fully-qualified path to call one of them explicitly
21    |
22 LL -     target.get(10.0); // (used to crash here)
23 LL +     <_ as std::slice::SliceIndex<_>>::get(target, 10.0); // (used to crash here)

24    |
25 LL -     target.get(10.0); // (used to crash here)
- LL +     <_ as object::read::elf::relocation::Relr>::get(&target, 10.0); // (used to crash here)
27    |
28 
29 error: aborting due to 1 previous error


The actual stderr differed from the expected stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args.rs`

error: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2" "--target=wasm32-wasip1" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/wasm32-wasip1/native/rust-test-helpers"
stdout: none
--- stderr -------------------------------
error[E0308]: mismatched types
##[error]  --> /checkout/tests/ui/mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args.rs:4:16
   |
LL |     target.get(10.0); // (used to crash here)
   |            --- ^^^^ expected `i32`, found floating-point number
   |            |
   |            arguments to this method are incorrect
   |
note: method defined here
  --> /checkout/tests/ui/mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args.rs:22:12
   |
LL |     pub fn get(&self, data: i32) {
   |            ^^^        ---------
note: the `get` call is resolved to the method in `Target`, shadowing the method of the same name on trait `RandomTrait`
  --> /checkout/tests/ui/mismatched_types/diagnostic-method-lookup-returns-sig-with-fewer-args.rs:4:12
   |
LL |     target.get(10.0); // (used to crash here)
   |            ^^^ refers to `Target::get`
help: you might have meant to call the other method; you can use the fully-qualified path to call it explicitly
   |
LL -     target.get(10.0); // (used to crash here)
LL +     <_ as std::slice::SliceIndex<_>>::get(target, 10.0); // (used to crash here)
   |

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0308`.

rustbot assigned davidtwco Mar 10, 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 10, 2026

estebank commented Mar 10, 2026

View reviewed changes

estebank mentioned this pull request Mar 10, 2026

Detect inherent method behind deref being shadowed by trait method #153674

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davidtwco approved these changes Mar 25, 2026

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JonathanBrouwer mentioned this pull request Mar 25, 2026

Rollup of 21 pull requests #154378

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estebank added 4 commits March 25, 2026 19:09

Account for inherent methods

0a5a78c

Tweak output

a72d226

Tweak wording on "other methods available" note

0bd2852

Handle correct gramar in the face of a single other option, or many.

estebank force-pushed the suggest-fully-qualified-path branch from 67036af to 0bd2852 Compare March 25, 2026 19:22

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JonathanBrouwer mentioned this pull request Mar 26, 2026

Rollup of 9 pull requests #154438

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matthiaskrgr mentioned this pull request Mar 26, 2026

Rollup of 7 pull requests #154440

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Rollup of 7 pull requests #154448

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Auto merge of #153662 - estebank:suggest-fully-qualified-path, r=<try>

7709c37

Suggest fully qualified path on method name collision try-job: test-various

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