Handle IrFunctionExpression in SAM conversion.

We will see that case when we will switch to Kotlin 2.0.21.

PiperOrigin-RevId: 688578869

transpiler/java/com/google/j2cl/transpiler/frontend/kotlin/CompilationUnitBuilder.kt

@@ -84,7 +84,6 @@ import com.google.j2cl.transpiler.frontend.common.AbstractCompilationUnitBuilder
 import com.google.j2cl.transpiler.frontend.kotlin.ir.IntrinsicMethods
 import com.google.j2cl.transpiler.frontend.kotlin.ir.findFunctionByName
 import com.google.j2cl.transpiler.frontend.kotlin.ir.getArguments
-import com.google.j2cl.transpiler.frontend.kotlin.ir.getFunctionExpression
 import com.google.j2cl.transpiler.frontend.kotlin.ir.getNameSourcePosition
 import com.google.j2cl.transpiler.frontend.kotlin.ir.getParameters
 import com.google.j2cl.transpiler.frontend.kotlin.ir.getSourcePosition
@@ -98,6 +97,7 @@ import com.google.j2cl.transpiler.frontend.kotlin.ir.isUnitInstanceReference
 import com.google.j2cl.transpiler.frontend.kotlin.ir.javaName
 import com.google.j2cl.transpiler.frontend.kotlin.ir.resolveLabel
 import com.google.j2cl.transpiler.frontend.kotlin.ir.typeSubstitutionMap
+import com.google.j2cl.transpiler.frontend.kotlin.ir.unfoldExpression
 import com.google.j2cl.transpiler.frontend.kotlin.lower.IrForInLoop
 import com.google.j2cl.transpiler.frontend.kotlin.lower.IrForLoop
 import com.google.j2cl.transpiler.frontend.kotlin.lower.IrSwitch
@@ -1289,7 +1289,7 @@ class CompilationUnitBuilder(
   }
 
   private fun convertSamConversion(irTypeOperatorCall: IrTypeOperatorCall): Expression {
-    val expression = irTypeOperatorCall.argument
+    val expression = irTypeOperatorCall.unfoldExpression()
     val functionalTypeDescriptor = environment.getDeclaredTypeDescriptor(irTypeOperatorCall.type)
     return when (expression) {
       is IrFunctionReference -> createFunctionExpression(functionalTypeDescriptor, expression)
@@ -1300,13 +1300,10 @@ class CompilationUnitBuilder(
           convertQualifier(expression),
           expression.getter,
         )
+      is IrFunctionExpression -> createFunctionExpression(functionalTypeDescriptor, expression)
       else ->
-        // TODO(b/225955286): Implement conversion functionality from things that are not
-        // lambdas.
-        createFunctionExpression(
-          functionalTypeDescriptor,
-          irTypeOperatorCall.getFunctionExpression(),
-        )
+        // TODO(b/225955286): Implement conversion functionality from things that are not lambdas.
+        throw IllegalStateException("Unsupported SAM conversion ${irTypeOperatorCall.dump()}")
     }
   }
 

transpiler/java/com/google/j2cl/transpiler/frontend/kotlin/ir/IrUtils.kt

@@ -75,6 +75,7 @@ import org.jetbrains.kotlin.ir.expressions.IrFunctionReference
 import org.jetbrains.kotlin.ir.expressions.IrGetField
 import org.jetbrains.kotlin.ir.expressions.IrLoop
 import org.jetbrains.kotlin.ir.expressions.IrMemberAccessExpression
+import org.jetbrains.kotlin.ir.expressions.IrPropertyReference
 import org.jetbrains.kotlin.ir.expressions.IrSetField
 import org.jetbrains.kotlin.ir.expressions.IrSetValue
 import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
@@ -130,12 +131,14 @@ import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.utils.addIfNotNull
 
 /** Returns the actual function expression from inside a nested type operator. */
-fun IrTypeOperatorCall.getFunctionExpression(): IrFunctionExpression =
+fun IrTypeOperatorCall.unfoldExpression(): IrExpression =
   // TODO(b/225955286): Fix to handle the general case.
   argument.let {
     when (it) {
-      is IrTypeOperatorCall -> it.getFunctionExpression()
-      is IrFunctionExpression -> it
+      is IrTypeOperatorCall -> it.unfoldExpression()
+      is IrFunctionExpression,
+      is IrFunctionReference,
+      is IrPropertyReference -> it
       else -> throw IllegalStateException("Unsupported arguments type")
     }
   }