Extension properties, fields and operators

[ghost]

A long time ago Extension Methods were added to C# and VB.
I propose to add extension properties and extension fields too.

[reduckted]

#73

[ghost]

#114 would be easy if Extension Operators are implemented.

[ghost]

#204 might be unnecessary when everything can be extended by extensions, but it should then be possible to shadow an existing method, property, etc with an extension method.

[Bill-McC]

IIRC the design for extension methods is they are not to shadow methods in the type. This is important so that importing a library with extensions doesn't hijack and change methods intrinsic to the type. Extensions extend but not break encapsulation. Get Outlook for Android<https://aka.ms/ghei36>

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[reduckted]

That's correct. You will never ever be able to shadow an instance method by using an extension method.

When an in-scope instance method has a signature that is compatible with the arguments of a calling statement, the instance method is chosen in preference to any extension method. The instance method has precedence even if the extension method is a better match.

From Extension Methods, Instance Methods, and Properties.

[ghost]

And I agree with it; as you describe, the side effects of shadowing extensions are unacceptable.
EDI 3 days later
I thought about it and I think it would be save when a shadowing extension is only allowed when defined as Friend (assembly scope).

[ghost]

dotnet/csharplang#192
dotnet/roslyn#6136

[KathleenDollard]

This is a great idea, and is being discussed. Happily, this has a Roslyn proposal. If that moves forward, extending :-) it to VB should be straightforward.

More recent than dotnet/roslyn#6136 is dotnet/roslyn#11159