compiletime.summonInline should yield the missing implicit error

[soronpo]

Compiler version

v3.0.0-RC3

Minimized code

@annotation.implicitNotFound("Missing")
trait Missing
val x = compiletime.summonInline[Missing] 

Output

3 |val x = compiletime.summonInline[Missing]
  |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |        cannot reduce summonFrom with
  |         patterns :  case given t @ _:Missing

Expectation

expecting "Missing" error.

@nicolasstucki I can take care of this, by implementing summonInline directly in the compiler.
If this is acceptable, I will submit a PR.

[nicolasstucki]

Yes, summonInline should be implemented directly in the compiler. It should share as much logic as possible with summonFrom. Maybe we can even turn it around and implement summonFrom based on summonInline.

[soronpo]

@nicolasstucki I have a related question. As an experiment I implemented

transparent inline def summonOrError[T]: Either[String, T] =

This either enables us to get the error message and possibly pattern match on it as well.
It worked well, but the problem is that within a case statement, we loose refinement:

inline compiletime.summonOrError[Foo] match
  case Right(v : Foo) => v
  case Left(msg) if msg == "Some Message" => compiletime.error("Got my message")
  case Left(msg) => compiletime.error(msg) //not possible to 

Do you think something can be done to allow this concept, or we say "nevermind" as this logic can be implemented in macros?

[nicolasstucki]

Something can be done but it is probably tricky. Macros might be simpler to handle in this case.