Hello we're trying to generate the following class...

# compiler

[Jacob Applin]

Hello we're trying to generate the following class and primary constructor using k2 fir:

// Given this 
@MyAnnotation public class Foo(public val param0: String)

// Generate the following class:
public class FooGenerated(public val param0: String)

Is it possible to do this just by implementing generateConstructors and using buildPrimaryConstructor inside of FirDeclarationGenerationExtension ? Or would we need to instead handle part of this in IR and generate a body that assigns a constructor arg to the class field?

[Jacob Applin]

When trying to do this in just FIR the class is being generated, however when trying to add the val parameter to the primary constructor the following error is happening:

Caused by: java.lang.IllegalStateException: Cannot find variable param0: R|kotlin/String| in local storage

This is the implementation of generateConstructors:

override fun generateConstructors(context: MemberGenerationContext): List<FirConstructorSymbol> {
  val classId = context.owner.classId
  val targetConstructor = toGenerate.getValue(classId)

  return buildPrimaryConstructor {
    origin = Key.origin
    moduleData = session.moduleData
    symbol = FirConstructorSymbol(classId)  
    status = FirResolvedDeclarationStatusImpl(
      visibility = Visibilities.Public,
      modality = Modality.FINAL,
      effectiveVisibility = EffectiveVisibility.Public,
    )
    returnTypeRef = FirImplicitTypeRefImplWithoutSource
    dispatchReceiverType = FirRegularClassSymbol(classId).constructType()
      valueParameters.addAll(
        targetConstructor.valueParameterSymbols.map { param ->
          buildValueParameter {
            name = param.name
            symbol = param
            origin = Key.origin
            moduleData = session.moduleData
            returnTypeRef = param.resolvedReturnType.toFirResolvedTypeRef()
            containingFunctionSymbol = [e-mail]
            isCrossinline = false
            isNoinline = false
            isVararg = false
          }
        },
      )
    }.symbol.let(::toList)
  }
}

[dmitriy.novozhilov]

1. Don't use build... functions to create FIR declarations, use create... ones (link)
2. Yes, it is possible. You need to generate constructor and then generate properties with initializer. For the initializer you need to create FirPropertyAccessExpression node which will point to the corresponding value parameter of the constructor. To udnerstand how to correctly generate this node I recoemmend you to inspect with debugger how the FIR for the same code written manually looks like

[Jacob Applin]

Ah thank you! Will try that and let you know if it works.

[Jacob Applin]

createConstructor call worked for me thanks again for the help