Give autocomplete suggestions for programmatic structural types

[markehammons]

Is your feature request related to a problem? Please describe.

class Structural(map: Map[String, Any]) extends Selectable:
  def selectDynamic(name: String) = map(name)

type Person = Structural{ val: name; val age: Int }

val p = new Structural(Map("name" -> "jacob", "age" -> 5)).asInstanceOf[Person]

p.name //I should see name + age in autocomplete

Describe the solution you'd like

Provide refinement values/definitions in autocomplete options

Describe alternatives you've considered

Going without autocomplete is the alternative

Additional contex

No response

Search terms

programmatic structural types autocomplete

[tgodzik]

Thanks for reporting! This already works in Scala 2, we should remember to add it to Scala 3 support.

[tambonbon]

In mtag/scala2 there are Keyword and Keywords that suggest autocompletion.. Might be a good starting point for Scala 3 support?

[tambonbon]

Found this https://github.com/lampepfl/dotty/blob/master/compiler/src/dotty/tools/dotc/interactive/Completion.scala

[olafurpg]

Is this an mtags issue or something that needs to be fixed in Scala 3? Mtags doesn’t do anything custom for structural types iirc.

[tgodzik]

Is this an mtags issue or something that needs to be fixed in Scala 3? Mtags doesn’t do anything custom for structural types iirc.

I haven't been able to check that exactly, this might well be fixable in the compiler.

[kitlangton]

This would be amazing :) If this existed, generating Selectable types at compile-time could be a decent replacement for annotation macros.

[olafurpg]

Completions work like this with structural types in Scala 2. I’m not 100% familiar with how Metals uses the Scala 3 compiler but this sounds like a feature that is missing from the compiler, not Metals.