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Tracking issue for future-incompatbility lint ambiguous_associated_items #57644

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2 of 3 tasks
petrochenkov opened this issue Jan 15, 2019 · 1 comment
Open
2 of 3 tasks

Tracking issue for future-incompatbility lint ambiguous_associated_items #57644

petrochenkov opened this issue Jan 15, 2019 · 1 comment
Labels
A-associated-items Area: Associated items (types, constants & functions) A-lint Area: Lints (warnings about flaws in source code) such as unused_mut. C-future-incompatibility Category: Future-incompatibility lints C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-lang Relevant to the language team, which will review and decide on the PR/issue.

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@petrochenkov
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petrochenkov commented Jan 15, 2019 •
edited by Centril
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What is this lint about

With variants being resolved as inherent associated items (rust-lang/rfcs#2338) code like this become ambiguous:

enum E {
    V
}

trait Tr {
    type V;
    fn f() -> Self::V;
}

impl Tr for E {
    type V = u8;
    fn f() -> Self::V { 0 } // `Self::V` in type namespace may refer to both variant and associated type
}

This is not a problem right now, because variants cannot be used in type positions, but it may become a problem in the future if rust-lang/rfcs#2593 is accepted.
So this lints warns against cases like this and recommends to rewrite them as <Self as Tr>::V.

How to fix this warning/error

Explicitly disambiguate in favor of associated types from traits: <Type as Trait>::Ambiguous.

Current status
@petrochenkov petrochenkov added A-lint Area: Lints (warnings about flaws in source code) such as unused_mut. T-lang Relevant to the language team, which will review and decide on the PR/issue. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. C-future-incompatibility Category: Future-incompatibility lints labels Jan 15, 2019
@Centril Centril mentioned this issue Jan 18, 2019
Merged
3 tasks
@CAD97 CAD97 mentioned this issue Feb 6, 2019
Closed
@petrochenkov petrochenkov mentioned this issue Apr 12, 2019
Merged
This was referenced Apr 30, 2019
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kennytm added a commit to kennytm/rust that referenced this issue May 2, 2019
@kennytm
Rollup merge of rust-lang#59928 - petrochenkov:denyambass, r=varkor
50be6df 
Make deprecation lint `ambiguous_associated_items` deny-by-default

As requested by r? @Centril

cc rust-lang#57644
Centril added a commit to Centril/rust that referenced this issue May 2, 2019
@Centril
Rollup merge of rust-lang#59928 - petrochenkov:denyambass, r=varkor
7d7787d 
Make deprecation lint `ambiguous_associated_items` deny-by-default

As requested by r? @Centril

cc rust-lang#57644
Centril added a commit to Centril/rust that referenced this issue May 3, 2019
@Centril
Rollup merge of rust-lang#59928 - petrochenkov:denyambass, r=varkor
e9509f8 
Make deprecation lint `ambiguous_associated_items` deny-by-default

As requested by r? @Centril

cc rust-lang#57644
@jebrosen jebrosen mentioned this issue May 9, 2019
Closed
@Centril Centril mentioned this issue Jun 9, 2019
Merged
illicitonion pushed a commit to illicitonion/num_enum that referenced this issue Jun 30, 2019
@rgiot @illicitonion
Fix ambiguous_associated_items case (#4)
5f15458 
Hello,

my enum looks like that:

```rust
#[derive(IntoPrimitive, TryFromPrimitive, Copy, Clone, PartialEq, Debug)]
#[repr(u8)]
pub enum BasicTokenNoPrefix {
    EndOfTokenisedLine = 0,
    StatementSeparator = 1,

    [...]
    Error,
    [...]
}
```

and I obtain this compilation error when using it:

```
error: ambiguous associated item
 --> src/basic/tokens.rs:7:10
  |
7 | #[derive(IntoPrimitive, TryFromPrimitive, Copy, Clone, PartialEq, Debug)]
  |          ^^^^^^^^^^^^^^^^
  |
  = note: #[deny(ambiguous_associated_items)] on by default
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = note: for more information, see issue #57644 <rust-lang/rust#57644>
note: `Error` could refer to variant defined here
 --> src/basic/tokens.rs:145:5
  |
14|     Error,
  |     ^^^^^
note: `Error` could also refer to associated type defined here
```


This patch allows to fix this issue.
@mkpankov
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Self::V in type namespace may refer to both variant and associated type

How is a variant present in type namespace? Syntactically only type is possible in that position, a function can't return a variant of an enum.

tylerwhall added a commit to tylerwhall/strum that referenced this issue Nov 18, 2021
@tylerwhall
Disambiguate associated items in trait impls
8410f95 
The addition of TryFrom<&str> for EnumString breaks for enums that have
a variant called "Error". Rewrite as <Self as Trait> where associated
types are used as the return type for trait functions.

Example:

```rust
pub enum Test {
    Error,
}
```

error: ambiguous associated item
   --> src/lib.rs:3:10
    |
3   | #[derive(EnumString)]
    |          ^^^^^^^^^^
    |
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
tylerwhall added a commit to tylerwhall/strum that referenced this issue Nov 18, 2021
@tylerwhall
Disambiguate associated items in trait impls
503380d 
The addition of TryFrom<&str> for EnumString breaks for enums that have
a variant called "Error". Rewrite as <Self as Trait> where associated
types are used as the return type for trait functions.

Example:

```rust
pub enum Test {
    Error,
}
```

error: ambiguous associated item
   --> src/lib.rs:3:10
    |
3   | #[derive(EnumString)]
    |          ^^^^^^^^^^
    |
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
tylerwhall added a commit to tylerwhall/strum that referenced this issue Nov 18, 2021
@tylerwhall
Disambiguate associated items in trait impls
77c854c 
The addition of TryFrom<&str> for EnumString breaks for enums that have
a variant called "Error". Rewrite as <Self as Trait> where associated
types are used as the return type for trait functions.

Example:

```rust
#[derive(EnumString)]
pub enum Test {
    Error,
}
```

error: ambiguous associated item
   --> src/lib.rs:3:10
    |
3   | #[derive(EnumString)]
    |          ^^^^^^^^^^
    |
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
tylerwhall added a commit to tylerwhall/strum that referenced this issue Nov 18, 2021
@tylerwhall
Disambiguate associated items in trait impls
1a946d5 
The addition of TryFrom<&str> for EnumString breaks for enums that have
a variant called "Error". Rewrite as <Self as Trait> where associated
types are used as the return type for trait functions.

Example:

```rust
#[derive(EnumString)]
pub enum Test {
    Error,
}
```

error: ambiguous associated item
   --> src/lib.rs:3:10
    |
3   | #[derive(EnumString)]
    |          ^^^^^^^^^^
    |
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
@tylerwhall tylerwhall mentioned this issue Nov 18, 2021
Merged
tylerwhall added a commit to tylerwhall/strum that referenced this issue Nov 19, 2021
@tylerwhall
Disambiguate associated items in trait impls
a483498 
The addition of TryFrom<&str> for EnumString breaks for enums that have
a variant called "Error". Rewrite as <Self as Trait> where associated
types are used as the return type for trait functions.

Example:

```rust
pub enum Test {
    Error,
}
```

error: ambiguous associated item
   --> src/lib.rs:3:10
    |
3   | #[derive(EnumString)]
    |          ^^^^^^^^^^
    |
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
Peternator7 pushed a commit to Peternator7/strum that referenced this issue Nov 19, 2021
@tylerwhall
Disambiguate associated items in trait impls (#193)
1e3acb6 
The addition of TryFrom<&str> for EnumString breaks for enums that have
a variant called "Error". Rewrite as <Self as Trait> where associated
types are used as the return type for trait functions.

Example:

```rust
pub enum Test {
    Error,
}
```

error: ambiguous associated item
   --> src/lib.rs:3:10
    |
3   | #[derive(EnumString)]
    |          ^^^^^^^^^^
    |
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
hunts pushed a commit to hunts/capnproto-rust that referenced this issue Jan 30, 2023
avoid ambiguous associated item in TryFrom implementations
efe7ee6 
This was previously accepted by the compiler but is being
phased out; it will become a hard error in a future release!

See also: rust-lang/rust#57644
hunts added a commit to hunts/capnproto-rust that referenced this issue Jan 30, 2023
@hunts
avoid ambiguous associated item in TryFrom implementations
991aca3 
This was previously accepted by the compiler but is being
phased out; it will become a hard error in a future release!

See also: rust-lang/rust#57644
hunts added a commit to hunts/capnproto-rust that referenced this issue Jan 30, 2023
@hunts
avoid ambiguous associated item in TryFrom implementations
a5c3f02 
This was previously accepted by the compiler but is being
phased out; it will become a hard error in a future release!

See also: rust-lang/rust#57644
hunts added a commit to hunts/capnproto-rust that referenced this issue Jan 30, 2023
@hunts
avoid ambiguous associated item in TryFrom implementations
790dcdc 
This was previously accepted by the compiler but is being
phased out; it will become a hard error in a future release!

See also: rust-lang/rust#57644
@hunts hunts mentioned this issue Jan 30, 2023
Closed
@mlwilkerson mlwilkerson mentioned this issue Nov 1, 2023
Closed
@cmrschwarz cmrschwarz mentioned this issue Mar 12, 2024
Merged
@github-actions github-actions bot mentioned this issue Apr 9, 2024
Merged
caspermeijn added a commit to caspermeijn/prost that referenced this issue Jul 9, 2024
@caspermeijn
fix: Enum variant named Error causes ambiguous item
62e7a87 
The generated code uses `Self::Error` to refer to `::prost::UnknownEnumValue`, but the term `Error` is not unique when an enum variant is called `Error`. Use the full type name to resolve the ambiguity.

The compiler reported:
```
error: ambiguous associated item
   --> /home/ircdev/src/prost/target/debug/build/tests-no-std-e27db7197924752f/out/enum_keyword_variant.rs:2:68
    |
2   | #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
    |                                                                    ^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
note: `Error` could refer to the variant defined here
   --> /home/ircdev/src/prost/target/debug/build/tests-no-std-e27db7197924752f/out/enum_keyword_variant.rs:10:5
    |
10  |     Error = 4,
    |     ^^^^^
note: `Error` could also refer to the associated type defined here
   --> /home/ircdev/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:682:5
    |
682 |     type Error;
    |     ^^^^^^^^^^
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = note: this error originates in the derive macro `::prost::Enumeration` (in Nightly builds, run with -Z macro-backtrace for more info)
```
github-merge-queue bot pushed a commit to tokio-rs/prost that referenced this issue Jul 9, 2024
@caspermeijn
fix: Enum variant named Error causes ambiguous item (#1098)
26463f4 
The generated code uses `Self::Error` to refer to `::prost::UnknownEnumValue`, but the term `Error` is not unique when an enum variant is called `Error`. Use the full type name to resolve the ambiguity.

The compiler reported:
```
error: ambiguous associated item
   --> /home/ircdev/src/prost/target/debug/build/tests-no-std-e27db7197924752f/out/enum_keyword_variant.rs:2:68
    |
2   | #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
    |                                                                    ^^^^^^^^^^^^^^^^^^^^
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
    = note: for more information, see issue #57644 <rust-lang/rust#57644>
note: `Error` could refer to the variant defined here
   --> /home/ircdev/src/prost/target/debug/build/tests-no-std-e27db7197924752f/out/enum_keyword_variant.rs:10:5
    |
10  |     Error = 4,
    |     ^^^^^
note: `Error` could also refer to the associated type defined here
   --> /home/ircdev/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/convert/mod.rs:682:5
    |
682 |     type Error;
    |     ^^^^^^^^^^
    = note: `#[deny(ambiguous_associated_items)]` on by default
    = note: this error originates in the derive macro `::prost::Enumeration` (in Nightly builds, run with -Z macro-backtrace for more info)
```
@fmease fmease changed the title Tracking issue for ambiguous_associated_items compatibility lint Tracking issue for future-incompatbility lint ambiguous_associated_items Sep 14, 2024
@fmease fmease added C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. A-associated-items Area: Associated items (types, constants & functions) labels Sep 14, 2024
LilyFoote added a commit to PyO3/pyo3 that referenced this issue Nov 21, 2024
@LilyFoote
Fix #4723: ambiguous associated item in #[pyclass]
8aaabb2 
This uses the fix described in rust-lang/rust#57644
LilyFoote added a commit to PyO3/pyo3 that referenced this issue Nov 22, 2024
@LilyFoote
Fix #4723: ambiguous associated item in #[pyclass]
a858c2e 
This uses the fix described in rust-lang/rust#57644
LilyFoote added a commit to PyO3/pyo3 that referenced this issue Nov 22, 2024
@LilyFoote
Fix #4723: ambiguous associated item in #[pyclass]
d7d5b54 
This uses the fix described in rust-lang/rust#57644
LilyFoote added a commit to PyO3/pyo3 that referenced this issue Nov 23, 2024
@LilyFoote
Fix #4723: ambiguous associated item in #[pyclass]
5335b28 
This uses the fix described in rust-lang/rust#57644

Also apply fix to `#[derive(IntoPyObject)]`.
LilyFoote added a commit to PyO3/pyo3 that referenced this issue Nov 23, 2024
@LilyFoote
Fix #4723: ambiguous associated item in #[pyclass]
f82ca32 
This uses the fix described in rust-lang/rust#57644

Also apply fix to `#[derive(IntoPyObject)]`.
github-merge-queue bot pushed a commit to PyO3/pyo3 that referenced this issue Nov 23, 2024
@LilyFoote
Fix ambiguous associated item error (#4725)
9681b54 
* Add test for ambiguous associated item

The `#[pyclass]` macro implements `IntoPyObject` for the annotated enum.
When the enum has any of `Error`, `Output` or `Target` as members, this
clashes with the associated types of `IntoPyObject`.

This also happens when deriving `IntoPyObject` directly.

* Fix #4723: ambiguous associated item in #[pyclass]

This uses the fix described in rust-lang/rust#57644

Also apply fix to `#[derive(IntoPyObject)]`.
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A-associated-items Area: Associated items (types, constants & functions) A-lint Area: Lints (warnings about flaws in source code) such as unused_mut. C-future-incompatibility Category: Future-incompatibility lints C-tracking-issue Category: A tracking issue for an RFC or an unstable feature. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. T-lang Relevant to the language team, which will review and decide on the PR/issue.
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@mkpankov @petrochenkov @fmease