Skip to content

Extensions: misc validation #9274

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

Merged
jcouv merged 3 commits into from
Apr 3, 2025
Merged

Extensions: misc validation #9274

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
2c2ecad
Extensions: misc validation
jcouv Apr 2, 2025
af00f0d
Document EnumeratorCancellation restriction
jcouv Apr 2, 2025
2462813
Clarify `[EnumeratorCancellation]` attribute usage for receiver param...
Apr 2, 2025
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
16 changes: 13 additions & 3 deletions proposals/extensions.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -98,8 +98,11 @@ public static class Enumerable
The type in the receiver specification is referred to as the _receiver type_ and the parameter name,
if present, is referred to as the _receiver parameter_.

If the _receiver parameter_ has an identifier, the _receiver type_ may not be static.
The _receiver parameter_ is only allowed to have the refness modifiers listed below and `scoped`.
If the _receiver parameter_ is named, the _receiver type_ may not be static.
The _receiver parameter_ is not allowed to have modifiers if it is unnamed, and
it is only allowed to have the refness modifiers listed below and `scoped` otherwise.
The _receiver parameter_ bears the same restrictions as the first parameter of a classic extension method.
The `[EnumeratorCancellation]` attribute is ignored if it is placed on the _receiver parameter_.

### Extension members

Expand Down Expand Up @@ -131,7 +134,10 @@ public static class Enumerable
}
```

It is an error to specify the `partial` modifier on a member of an extension declaration.
It is an error to specify the following modifiers on a member of an extension declaration:
`abstract`, `virtual`, `override`, `new`, `sealed`, `extern`, `partial`, and `protected` (and related accessibility modifiers).
Properties in extension declarations may not have `init` accessors.
The instance members are disallowed if the _receiver parameter_ is unnamed.

### Refness

Expand Down Expand Up @@ -480,6 +486,10 @@ static class CollectionExtensions
}
```

## Breaking changes

Types and aliases may not be named "extensions".

## Open issues

- ~~Confirm `extension` vs. `extensions` as the keyword~~ (answer: `extension`, LDM 2025-03-24)
Expand Down