Every explanation is printed twice with `-explain` and sbt

[mrdziuban]

Compiler version

3.3.1

Minimized code

I'm not sure if this is an issue with Scala or sbt, so please let me know if I should open an issue with sbt instead!

https://github.com/mrdziuban/dotty-explain-issue

val test = nonExistent

Output

[error] -- [E006] Not Found Error: /Users/matt/dotty-explain-test/src/main/scala/example/Test.scala:3:11
[error] 3 |val test = nonExistent
[error]   |           ^^^^^^^^^^^
[error]   |           Not found: nonExistent
[error]   |-----------------------------------------------------------------------------
[error]   | Explanation (enabled by `-explain`)
[error]   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]   | The identifier for `nonExistent` is not bound, that is,
[error]   | no declaration for this identifier can be found.
[error]   | That can happen, for example, if `nonExistent` or its declaration has either been
[error]   | misspelt or if an import is missing.
[error]    -----------------------------------------------------------------------------
[error] Explanation
[error] ===========
[error] The identifier for `nonExistent` is not bound, that is,
[error] no declaration for this identifier can be found.
[error] That can happen, for example, if `nonExistent` or its declaration has either been
[error] misspelt or if an import is missing.

Expectation

The explanation should only be printed once

[som-snytt]

I have to repeat everything to my teenager, and more than twice. They should just call this parent mode.

[som-snytt]

There are a couple of dimensions of freedom -- a previous improvement plus something for metals -- but I think the improvement to render the explanation with the message is preferable to the old big blue explanations header, which is presumptively deprecated.

I don't know how to test if whatever API for metals is satisfied!

[mrdziuban]

Not 100% sure if scastie uses metals (I think it does?), but for what it's worth, it only shows the explanation with the blue header

[som-snytt]

I see I accidentally deprecated the blue explanation; I'll revert that part.

I did not drill thru the API, but Problem distinguishes message and optional rendered, where message gets the blue explanation and rendered gets the boxed explanation. If clients are happy with this division or duplication of labor, then that seems fine to me.