Support cleanup actions in class completers#23515
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odersky merged 1 commit intoscala:mainfrom Jul 14, 2025
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Needed to break the loop between completion of class and companion object. If we try to complete the class first, and completion needs the companion object (for instance for processing an import) then the companion object completion would consult the companion class info for constructor that need a constructor proxy in the object. This can lead to a cyclic reference. We now break the cycle by delaying adding constructor proxies in this case to be the last completion action of the companion class.
mbovel
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Jul 14, 2025
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What happens if we actually do need the constructor proxy symbol while we complete the class?
I tried:
object ProtocolTransport
class MyAnnotation(arg: () => ProtocolTransport) extends scala.annotation.StaticAnnotation
import ProtocolTransport.*
@MyAnnotation(apply)
class ProtocolTransport()and was surprised to see it actually sees the symbol and then complains that the constructor proxy cannot be used as a value:
-- [E195] Type Error: defs.scala:7:14 ------------------------------------------
7 |@MyAnnotation(apply)
| ^^^^^
| constructor proxy method apply cannot be used as a value
|
| longer explanation available when compiling with `-explain`
So in that case that seems to be okay.
And in any case, we probably only enable more code to compile with this PR 👍
This was referenced Jul 23, 2025
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Needed to break the loop between completion of class and companion object. If we try to complete the class first, and completion needs the companion object (for instance for processing an import) then the companion object completion would consult the companion class info for constructor that need a constructor proxy in the object. This can lead to a cyclic reference.
We now break the cycle by delaying adding constructor proxies in this case to be the last completion action of the companion class.