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Two different versions of a crate interacting leads to unhelpful error messages #22750

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huonw opened this issue Feb 24, 2015 · 60 comments · Fixed by #28300
Open

Two different versions of a crate interacting leads to unhelpful error messages #22750

huonw opened this issue Feb 24, 2015 · 60 comments · Fixed by #28300
Labels
A-diagnostics Area: Messages for errors, warnings, and lints C-enhancement Category: An issue proposing an enhancement or a PR with one. D-confusing Diagnostics: Confusing error or lint that should be reworked. D-crate-version-mismatch Diagnostics: Errors or lints caused be the use of two different crate versions. D-newcomer-roadblock Diagnostics: Confusing error or lint; hard to understand for new users. P-medium Medium priority T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@huonw
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huonw commented Feb 24, 2015

https://github.com/huonw/bad-error-messages-a contains a crate a. https://github.com/huonw/bad-error-messages-bc contains two crates, b and c.

  • a contains a trait Foo and a function test that requires that trait.
  • b depends on a specific revision (8b532f5, not the HEAD) of a and contains a type Bar that implements a::Foo.
  • c depends on a's HEAD (happens to be 84cfe230) and b, and tries to use b::Bar with a::test.

c fails to compile despite Bar "clearly" implementing Foo... it's even displayed in the docs!

Cloning https://github.com/huonw/bad-error-messages-bc and running cargo build in the root (which is c) gives

   Compiling a v0.0.1 (https://github.com/huonw/bad-error-messages-a#84cfe230)
   Compiling a v0.0.1 (https://github.com/huonw/bad-error-messages-a?rev=8b532f5#8b532f51)
   Compiling b v0.0.1 (file:///home/huon/projects/test-rust/error-messages/c)
   Compiling c v0.0.1 (file:///home/huon/projects/test-rust/error-messages/c)
src/lib.rs:5:5: 5:12 error: the trait `a::Foo` is not implemented for the type `b::Bar` [E0277]
src/lib.rs:5     a::test(b::Bar);
                 ^~~~~~~
error: aborting due to previous error

There's no indication of the fundamental problem from either rustdoc or rustc: that there's two different versions of a being used, meaning a#84cfe230::Foo and a#8b532f5::Foo are different. Bar only implements the latter, but in c, the name a refers to a#84cfe230 so a::test(...) requires the former. (Using name#rev to represent the crate with that version.)

There is an indication of the difference in the example above, since a is compiled twice, but that comes from cargo, not rustc. This issue is focusing on the fact that rustc itself does not give helpful errors and/or allow tools like cargo to control those errors.

It would be nice if rustc:

  • disambiguated ambiguous names, probably by filepath/name by default
  • allowed cargo to specify semantically relevant info for the disambiguation e.g. pass in the version/revision/..., so that rustc can print foo#0.2.3 instead of the filepath/name
  • detected errors that may be caused by ambiguous names and noted it explicitly, e.g. when there is a error involving an ambiguous crate print (once) some extra lines like "note: there's multiple versions of crate ... in use": along with a listing of the possibilities.

(NB. I've used cargo to construct this example because it is the easiest way I can get two different versions of a crate. This appears in rust-lang/rust's makefiles too, where the std test runner is called "std" internally, but links against another crate called "std", i.e. the conventional standard library.)

@huonw huonw added the A-diagnostics Area: Messages for errors, warnings, and lints label Feb 24, 2015
@Hoverbear
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This bit me today with uuid! It took me a few minutes before I even understood that it wasn't "my" code that was giving this off.

@Kimundi
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Kimundi commented Feb 27, 2015

Related, its also annoying if only crate local paths get emitted, like in backtraces.

We need a way for crates to identify themself uniquely, and not just by an identifier. Maybe a scheme like <crate foo #ef12f212>::bar::baz?

@golddranks
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I was bitten by this too.

Kimundi: Agreed for the need to unique identification. But then again, in some cases the local path tells more directly where the problem is. I wonder if there are cases where path is better and cases where a hash is better. Or maybe some kind of hybrid: If version information from cargo is available, use that. If not, if version control information is available, use commit SSH, and if no other information exists, use a path...?

@huonw
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huonw commented Sep 8, 2015

Nominating for high priority. I think this is one of the main pain points people have when using cargo, and one of the major reasons for people complaining about cargo allowing multiple versions of a crate. It's usually easy to identify once you've seen it a few times, but it is a horribly confusing and annoying experience.

(Tagged with both compiler and tools since cargo presumably plays into this, but this is probably most relevant to the compiler subteam.)

@golddranks: the question of connecting semantically relevant info to crates is discussed a little in the issue. I think the best plan would external tools to pass in arbitrary strings connected to each crate, defaulting to the path, meaning rustc doesn't have to actually understand anything, just print strings (the compiler already has an --extern NAME=PATH argument that tools like cargo use, it could be extended to also allow --extern NAME#"ID"=PATH or something).

@steveklabnik
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I've also seen an increasing number of IRC questions about this.

On Sep 7, 2015, at 20:58, Huon Wilson [email protected] wrote:

Nominating for high priority. I think this is one of the main pain points people have when using cargo, and one of the major reasons for people complaining about cargo allowing multiple versions of a crate. It's usually easy to identify once you've seen it a few times, but it is a horribly confusing and annoying experience.

(Tagged with both compiler and tools since cargo presumably plays into this, but this is probably most relevant to the compiler subteam.)

@golddranks: the question of connecting semantically relevant info to crates is discussed a little in the issue. I think the best plan would external tools to pass in arbitrary strings connected to each crate, defaulting to the path, meaning rustc doesn't have to actually understand anything, just print strings (the compiler already has an --extern NAME=PATH argument that tools like cargo use, it could be extended to also allow --extern NAME#"ID"=PATH or something).


Reply to this email directly or view it on GitHub.

@Manishearth Manishearth self-assigned this Sep 8, 2015
@Manishearth
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I'll take a crack at this

@Manishearth
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I think at the very least, for mismatched type and unimplemented trait errors, if we detect a crate mismatch, we should mention it. Any other such errors?

@steveklabnik
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Mismatched type is the big one.

Being able to understand this would also help Rustdoc a lot, I think there are bugs open. (That way, we could know if something is a re-export or not)

Manishearth added a commit to Manishearth/rust that referenced this issue Sep 8, 2015
bors added a commit that referenced this issue Sep 9, 2015
Partially fixes #22750

I'll write a test for this when I figure out how to.

r? @eddyb

cc @steveklabnik
@Manishearth
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No no no github, I said "partial fix"

@Manishearth Manishearth reopened this Sep 9, 2015
@Manishearth
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Anyway, #28300 fixes the error when there's a type mismatch. "Can't find trait" will be a tad trickier

@hexsel
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hexsel commented Sep 9, 2015

I had a corner-case posted on Reddit that was even more confusing:

src/main.rs:9:45: 9:47 error: mismatched types:
 expected `&cookie::jar::CookieJar<'_>`,
 found `&cookie::jar::CookieJar<'_>`

I was using Hyper with the latest cookie crate. I did it because even though 'hyper' depends on 'cookie=0.1.21' or somesuch, I couldn't use 'cookie' on my program. I'll suggest a change on cargo if it doesn't yet exist.

@Manishearth
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Yeah, this should be fixed but the just-landed PR.

@nikomatsakis
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triage: P-medium -- we think that the most important cases here have been covered. If this issue continues to arise frequently on IRC, we could bump up the priority to high.

@rust-highfive rust-highfive added P-medium Medium priority and removed I-nominated labels Sep 17, 2015
@alexcrichton alexcrichton removed the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jan 27, 2016
@gilescope
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I would have loved to get a "Perhaps two different versions of crate crate_a2 are being used?" error message but didn't. In my case I had a derived impl for a different version of the trait. Took me a long while to figure out what was going on. A better error message would be most appreciated.

@robinmoussu
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I was bitten by this today. Since cargo tree has been added recently in stable, it was really easy to understand which version were used where. Maybe it could be possible to suggest using it in a note?

@Kixunil
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Kixunil commented Jun 19, 2020

@robinmoussu I just noticed cargo tree has -d switch. In that case, the switch should be suggested as well.

@edmorley
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I have another "trait not implemented" variation that isn't fixed by #66561 and doesn't seem to be similar to the previously mentioned testcases - I've filed it as #89143.

Dylan-DPC added a commit to Dylan-DPC/rust that referenced this issue Mar 19, 2023
…imulacrum

Add note for mismatched types because of circular dependencies

If you have crate A with a dependency on crate B, and crate B with a dev-dependency on A, then you might see "mismatched types" errors on types that seem to be equal. This PR adds a note that explains that the types are different, because crate B is compiled twice, one time with `cfg(test)` and one time without.

I haven't found a good way to create circular dependencies in UI tests, so I abused the incremental tests instead. As a bonus, incremental tests support "cpass" now.

related to rust-lang#22750
@jyn514 jyn514 added the D-crate-version-mismatch Diagnostics: Errors or lints caused be the use of two different crate versions. label Apr 25, 2023
@Allen-Webb
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I was helping someone troubleshoot a subcase of this and followed up with https://internals.rust-lang.org/t/better-error-when-trait-not-implemented-because-of-different-crate-version/18808. #73560 seems to do a good job of covering the case I ran into and it looks like a subcase of this issue.

@estebank
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cc rust-lang/compiler-team#635

estebank added a commit to estebank/rust that referenced this issue May 9, 2024
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
bors added a commit to rust-lang-ci/rust that referenced this issue May 13, 2024
…fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
estebank added a commit to estebank/rust that referenced this issue Jun 24, 2024
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
estebank added a commit to estebank/rust that referenced this issue Jul 12, 2024
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
estebank added a commit to estebank/rust that referenced this issue Jul 12, 2024
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
bors added a commit to rust-lang-ci/rust that referenced this issue Jul 12, 2024
…<try>

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
workingjubilee added a commit to workingjubilee/rustc that referenced this issue Jul 12, 2024
…r=fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Jul 12, 2024
…r=fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
estebank added a commit to estebank/rust that referenced this issue Aug 6, 2024
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Aug 6, 2024
…r=fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
estebank added a commit to estebank/rust that referenced this issue Aug 6, 2024
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Aug 6, 2024
…r=fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
rust-timer added a commit to rust-lang-ci/rust that referenced this issue Aug 7, 2024
Rollup merge of rust-lang#124944 - estebank:multiple-crate-versions, r=fee1-dead

On trait bound mismatch, detect multiple crate versions in dep tree

When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.

If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.

```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
 --> src/main.rs:4:18
  |
4 |     do_something(Type);
  |     ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
  |     |
  |     required by a bound introduced by this call
  |
help: you have multiple different versions of crate `dependency` in your dependency graph
 --> src/main.rs:1:5
  |
1 | use bar::do_something;
  |     ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
  |     ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
 --> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
  |
 ::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
  |
1 | pub struct Type;
  | ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
  | --------------- this is the required trait
note: required by a bound in `bar::do_something`
 --> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
  |
4 | pub fn do_something<X: Trait>(_: X) {}
  |                        ^^^^^ required by this bound in `do_something`
```

Address rust-lang#22750.
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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-confusing Diagnostics: Confusing error or lint that should be reworked. D-crate-version-mismatch Diagnostics: Errors or lints caused be the use of two different crate versions. D-newcomer-roadblock Diagnostics: Confusing error or lint; hard to understand for new users. P-medium Medium priority T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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