Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Document answered questions for field keyword #8528

Merged
merged 1 commit into from
Nov 25, 2024
Merged

Document answered questions for field keyword #8528

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
34 changes: 23 additions & 11 deletions proposals/field-keyword.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -734,16 +734,6 @@ When the backing field is considered *read-only*, the field emitted to metadata

Recommendation is accepted.

## Open LDM questions

### Feature name

Some options for the name of the feature:
1. semi-auto properties
1. field access for auto properties [LDM-2023-07-17](https://github.com/dotnet/csharplang/blob/main/meetings/2023/LDM-2023-07-17.md#compiler-check-in)
1. field-backed properties
1. field keyword

### Readonly context and `set`

Should a `set` accessor be allowed in a `readonly` context for a property that uses `field`?
Expand All @@ -766,6 +756,10 @@ struct S2
}
```

#### Answer

There could be scenarios for this where you're implementing a `set` accessor on a `readonly` struct and either passing it through, or throwing. We will allow this.

### `[Conditional]` code

Should the synthesized field be generated when `field` is used only in omitted calls to [*conditional methods*](https://github.com/dotnet/csharpstandard/blob/standard-v7/standard/attributes.md#22532-conditional-methods)?
Expand All @@ -789,6 +783,10 @@ For reference, fields for *primary constructor parameters* are generated in simi

**Recommendation**: The backing field is generated when `field` is used only in omitted calls to *conditional methods*.

#### Answer

`Conditional` code can have effects on non-conditional code, such as `Debug.Assert` changing nullability. It would be strange if `field` didn't have similar impacts. It is also unlikely to come up in most code, so we'll do the simple thing and accept the recommendation.

### Interface properties and auto-accessors

Is a combination of manually- and auto-implemented accessors recognized for an `interface` property where the auto-implemented accessor refers to a synthesized backing field?
Expand All @@ -806,4 +804,18 @@ interface I
}
```

**Recommendation**: Auto-accessors are recognized in `interface` properties, and the auto-accessors refer to a synthesized backing field. For an instance property, an error is reported that instance fields are not supported.
**Recommendation**: Auto-accessors are recognized in `interface` properties, and the auto-accessors refer to a synthesized backing field. For an instance property, an error is reported that instance fields are not supported.

#### Answer

Standardizing around the instance field itself being the cause of the error is consistent with partial properties in classes, and we like that outcome. The recommendation is accepted.

## Open LDM questions

### Feature name

Some options for the name of the feature:
1. semi-auto properties
1. field access for auto properties [LDM-2023-07-17](https://github.com/dotnet/csharplang/blob/main/meetings/2023/LDM-2023-07-17.md#compiler-check-in)
1. field-backed properties
1. field keyword