Warn on erased definitions with ???

Compiler version

3.0.0-RC1

Minimized example

erased given CanThrow[Ex1] = ???

Expectation

It should emit a warning suggesting the code

import scala.compiletime.erasedValue

erased given CanThrow[Ex1] = erasedValue

[nicolasstucki]

I have been considering something even more drastic. In this system the RHSs of definitions have no meaning at all, we only put some body as a placeholder. It also does not seem to be important if the definition is abstract or not. My suggestion would be to just not have an implementation. Make all of them look like abstract method. We would just need to define the signature which is all we care about.

erased given CanThrow[Ex1]

Furthermore with the erased classes idea we could just write

given CanThrow[Ex1]

[nicolasstucki]

The issue with that approach is that erased is a soft modifier. This would require changing it to a proper keyword or having some more complex syntactical rules.