Is it possible to create an extension method for interpolated string handler?

[voroninp]

It seems that compiler infers string in this case:

$"{x} {y} {z}".MyExtension();

If MyExtension's target type is this DefaultInterpolatedStringHandler str compiler does not consider this method as a valid one.

[CyrusNajmabadi]

No. Extensions only operate on things that have types. And the type of the thing is determined first before extensions are considered. This is something we've considered for the future, but that happens over at dotnet/csharplang. Thanks.

[voroninp]

Ok, thanks.

Though C#14 now makes an exception for collections, as it tries to convert them to spans and looks for overloads. ;-)

[CyrusNajmabadi]

I don't know what that means. AFAIK, we do not support extensions on collection expressions.

[voroninp]

I meant that compiler sometimes is indeed deciding on the type of the expression. I did not mean collection expressions though.
Just the fact that it now applies implicit conversion of the collection type to span and looks for the overloads which target span. Even for the extension methods.

[CyrusNajmabadi]

Sure. Just none of that applies to extension methods. I'd like it to, but it will take a language change :-)