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Misleading message: "error: the trait Foo is not implemented for the type Bar" #32611

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Yoric opened this issue Mar 30, 2016 · 1 comment · Fixed by #128786
Closed

Misleading message: "error: the trait Foo is not implemented for the type Bar" #32611

Yoric opened this issue Mar 30, 2016 · 1 comment · Fixed by #128786
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A-diagnostics Area: Messages for errors, warnings, and lints C-enhancement Category: An issue proposing an enhancement or a PR with one. D-crate-version-mismatch Diagnostics: Errors or lints caused be the use of two different crate versions. S-needs-repro Status: This issue has no reproduction and needs a reproduction to make progress. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@Yoric
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Yoric commented Mar 30, 2016

Consider three crates High, Mid and Low, where:

  • Mid depends on Low;
  • High depends on both Mid and Low.

This is a quite common case.

Now, it sometimes happens that the dependency of Mid is bumped to a more recent version of Low. If, however, the developer fails to bump the dependency of High to a more recent version of Low, surprising error messages arise.

In particular,

"error: the trait `Foo` is not implemented for the type `Bar`"

may arise, without any change to the code of either Foo or Bar.

It would be great if the compiler could detect the error and somehow print something along the liens of

"error: using conflicting versions of the trait `Foo` for type `Bar`. You are probably using two distinct versions of the same library."
@apasel422 apasel422 added the A-diagnostics Area: Messages for errors, warnings, and lints label May 16, 2016
@steveklabnik steveklabnik added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Mar 9, 2017
@Mark-Simulacrum Mark-Simulacrum added the C-enhancement Category: An issue proposing an enhancement or a PR with one. label Jul 24, 2017
@steveklabnik
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Triage: I feel like this has gotten better in certain cases, but not all. It would be nice to make a way to reproduce this more easily, but it's non-trivial.

@estebank estebank added the E-needs-mcve Call for participation: This issue has a repro, but needs a Minimal Complete and Verifiable Example label Oct 20, 2023
@jieyouxu jieyouxu added S-needs-repro Status: This issue has no reproduction and needs a reproduction to make progress. and removed E-needs-mcve Call for participation: This issue has a repro, but needs a Minimal Complete and Verifiable Example labels Feb 28, 2024
@fmease fmease added the D-crate-version-mismatch Diagnostics: Errors or lints caused be the use of two different crate versions. label Apr 22, 2024
tgross35 added a commit to tgross35/rust that referenced this issue Aug 17, 2024
…r=fee1-dead

Detect multiple crate versions on method not found

When a type comes indirectly from one crate version but the imported trait comes from a separate crate version, the called method won't be found. We now show additional context:

```
error[E0599]: no method named `foo` found for struct `dep_2_reexport::Type` in the current scope
 --> multiple-dep-versions.rs:8:10
  |
8 |     Type.foo();
  |          ^^^ method not found in `Type`
  |
note: there are multiple different versions of crate `dependency` in the dependency graph
 --> multiple-dep-versions.rs:4:32
  |
4 | use dependency::{do_something, Trait};
  |                                ^^^^^ `dependency` imported here doesn't correspond to the right crate version
  |
 ::: ~/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-1.rs:4:1
  |
4 | pub trait Trait {
  | --------------- this is the trait that was imported
  |
 ::: ~/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-2.rs:4:1
  |
4 | pub trait Trait {
  | --------------- this is the trait that is needed
5 |     fn foo(&self);
  |        --- the method is available for `dep_2_reexport::Type` here
```

Fix rust-lang#128569, fix rust-lang#110926, fix rust-lang#109161, fix rust-lang#81659, fix rust-lang#51458, fix rust-lang#32611. Follow up to rust-lang#124944.
tgross35 added a commit to tgross35/rust that referenced this issue Aug 17, 2024
…r=fee1-dead

Detect multiple crate versions on method not found

When a type comes indirectly from one crate version but the imported trait comes from a separate crate version, the called method won't be found. We now show additional context:

```
error[E0599]: no method named `foo` found for struct `dep_2_reexport::Type` in the current scope
 --> multiple-dep-versions.rs:8:10
  |
8 |     Type.foo();
  |          ^^^ method not found in `Type`
  |
note: there are multiple different versions of crate `dependency` in the dependency graph
 --> multiple-dep-versions.rs:4:32
  |
4 | use dependency::{do_something, Trait};
  |                                ^^^^^ `dependency` imported here doesn't correspond to the right crate version
  |
 ::: ~/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-1.rs:4:1
  |
4 | pub trait Trait {
  | --------------- this is the trait that was imported
  |
 ::: ~/rust/build/x86_64-unknown-linux-gnu/test/run-make/crate-loading/rmake_out/multiple-dep-versions-2.rs:4:1
  |
4 | pub trait Trait {
  | --------------- this is the trait that is needed
5 |     fn foo(&self);
  |        --- the method is available for `dep_2_reexport::Type` here
```

Fix rust-lang#128569, fix rust-lang#110926, fix rust-lang#109161, fix rust-lang#81659, fix rust-lang#51458, fix rust-lang#32611. Follow up to rust-lang#124944.
@bors bors closed this as completed in 9b318d2 Aug 17, 2024
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Labels
A-diagnostics Area: Messages for errors, warnings, and lints C-enhancement Category: An issue proposing an enhancement or a PR with one. D-crate-version-mismatch Diagnostics: Errors or lints caused be the use of two different crate versions. S-needs-repro Status: This issue has no reproduction and needs a reproduction to make progress. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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