FIR2IR: apply SAM conversion to arguments if needed

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/ConversionUtils.kt

@@ -459,3 +459,10 @@ fun FirClass<*>.irOrigin(firProvider: FirProvider): IrDeclarationOrigin = when {
     origin == FirDeclarationOrigin.Java -> IrDeclarationOrigin.IR_EXTERNAL_JAVA_DECLARATION_STUB
     else -> IrDeclarationOrigin.IR_EXTERNAL_DECLARATION_STUB
 }
+
+val IrType.isSamType: Boolean
+    get() {
+        val irClass = classOrNull ?: return false
+        val am = irClass.functions.singleOrNull { it.owner.modality == Modality.ABSTRACT }
+        return am != null
+    }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/CallAndReferenceGenerator.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.backend.generators
 
 import org.jetbrains.kotlin.fir.backend.*
+import org.jetbrains.kotlin.fir.declarations.FirAnonymousFunction
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirValueParameter
 import org.jetbrains.kotlin.fir.expressions.*
@@ -16,6 +17,7 @@ import org.jetbrains.kotlin.fir.references.FirReference
 import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
 import org.jetbrains.kotlin.fir.references.FirSuperReference
 import org.jetbrains.kotlin.fir.render
+import org.jetbrains.kotlin.fir.resolve.inference.isBuiltinFunctionalType
 import org.jetbrains.kotlin.fir.resolve.toSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
@@ -28,6 +30,7 @@ import org.jetbrains.kotlin.ir.declarations.IrProperty
 import org.jetbrains.kotlin.ir.expressions.IrErrorCallExpression
 import org.jetbrains.kotlin.ir.expressions.IrExpression
 import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
+import org.jetbrains.kotlin.ir.expressions.IrTypeOperator
 import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.types.*
@@ -325,22 +328,22 @@ internal class CallAndReferenceGenerator(
                 val argumentsCount = call.arguments.size
                 if (argumentsCount <= valueArgumentsCount) {
                     apply {
-                        val argumentMapping = call.argumentMapping
-                        if (argumentMapping != null && argumentMapping.isNotEmpty()) {
                         val calleeReference = when (call) {
                             is FirFunctionCall -> call.calleeReference
                             is FirDelegatedConstructorCall -> call.calleeReference
-                                else -> throw IllegalArgumentException("Unsupported call: ${call.render()}")
+                            else -> null
                         } as? FirResolvedNamedReference
                         val function = (calleeReference?.resolvedSymbol as? FirFunctionSymbol<*>)?.fir
                         val valueParameters = function?.valueParameters
-
+                        val argumentMapping = call.argumentMapping
+                        if (argumentMapping != null && argumentMapping.isNotEmpty()) {
                             if (valueParameters != null) {
                                 return applyArgumentsWithReorderingIfNeeded(argumentMapping, valueParameters)
                             }
                         }
                         for ((index, argument) in call.arguments.withIndex()) {
-                            val argumentExpression = visitor.convertToIrExpression(argument)
+                            val argumentExpression =
+                                visitor.convertToIrExpression(argument).applySamConversionIfNeeded(argument, valueParameters?.get(index))
                             putValueArgument(index, argumentExpression)
                         }
                     }
@@ -373,7 +376,7 @@ internal class CallAndReferenceGenerator(
             return IrBlockImpl(startOffset, endOffset, type, IrStatementOrigin.ARGUMENTS_REORDERING_FOR_CALL).apply {
                 for ((argument, parameter) in argumentMapping) {
                     val parameterIndex = valueParameters.indexOf(parameter)
-                    val irArgument = visitor.convertToIrExpression(argument)
+                    val irArgument = visitor.convertToIrExpression(argument).applySamConversionIfNeeded(argument, parameter)
                     if (irArgument.hasNoSideEffects()) {
                         putValueArgument(parameterIndex, irArgument)
                     } else {
@@ -388,7 +391,7 @@ internal class CallAndReferenceGenerator(
             }
         } else {
             for ((argument, parameter) in argumentMapping) {
-                val argumentExpression = visitor.convertToIrExpression(argument)
+                val argumentExpression = visitor.convertToIrExpression(argument).applySamConversionIfNeeded(argument, parameter)
                 putValueArgument(valueParameters.indexOf(parameter), argumentExpression)
             }
             return this
@@ -410,6 +413,21 @@ internal class CallAndReferenceGenerator(
         return false
     }
 
+    private fun IrExpression.applySamConversionIfNeeded(
+        argument: FirExpression,
+        parameter: FirValueParameter?
+    ): IrExpression {
+        if (parameter == null ||
+            parameter.returnTypeRef.coneTypeSafe<ConeKotlinType>()?.isBuiltinFunctionalType(session) == true
+        ) return this
+        if (argument !is FirLambdaArgumentExpression) return this
+        if (argument.expression !is FirAnonymousFunction) return this
+        if (argument.expression.typeRef == parameter.returnTypeRef) return this
+        val samType = parameter.returnTypeRef.toIrType()
+        if (!samType.isSamType) return this
+        return IrTypeOperatorCallImpl(this.startOffset, this.endOffset, samType, IrTypeOperator.SAM_CONVERSION, samType, this)
+    }
+
     private fun IrExpression.applyTypeArguments(access: FirQualifiedAccess): IrExpression {
         return when (this) {
             is IrMemberAccessExpressionBase -> {

compiler/testData/codegen/box/funInterface/basicFunInterfaceConversion.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
-// IGNORE_BACKEND_FIR: JVM_IR
 // SKIP_DCE_DRIVEN
 
 fun interface Foo {

compiler/testData/codegen/box/funInterface/equality/simpleLambdas.kt

@@ -1,5 +1,4 @@
 // IGNORE_BACKEND: JS_IR
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun interface FunInterface {
     fun invoke()

compiler/testData/ir/irText/expressions/funInterface/basicFunInterfaceConversion.fir.txt

@@ -26,7 +26,8 @@ FILE fqName:<root> fileName:/basicFunInterfaceConversion.kt
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun test (): kotlin.String declared in <root>'
         CALL 'public final fun foo (f: <root>.Foo): kotlin.String declared in <root>' type=kotlin.String origin=null
-          f: FUN_EXPR type=kotlin.Function0<kotlin.String> origin=LAMBDA
+          f: TYPE_OP type=<root>.Foo origin=SAM_CONVERSION typeOperand=<root>.Foo
+            FUN_EXPR type=kotlin.Function0<kotlin.String> origin=LAMBDA
               FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.String
                 BLOCK_BODY
                   RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.String declared in <root>.test'

compiler/testData/ir/irText/expressions/funInterface/partialSam.fir.txt

@@ -139,7 +139,8 @@ FILE fqName:<root> fileName:/partialSam.kt
       CALL 'public final fun runConversion (f1: <root>.Fn<kotlin.String, kotlin.Int>, f2: <root>.Fn<kotlin.Int, kotlin.String>): kotlin.Int declared in <root>.J' type=kotlin.Int origin=null
         $this: GET_VAR 'j: <root>.J declared in <root>.test' type=<root>.J origin=null
         f1: CALL 'public final fun <get-fsi> (): <root>.fsi.<no name provided> declared in <root>' type=<root>.fsi.<no name provided> origin=GET_PROPERTY
-        f2: FUN_EXPR type=kotlin.Function3<kotlin.String, kotlin.Int, kotlin.Int, kotlin.String> origin=LAMBDA
+        f2: TYPE_OP type=<root>.Fn<kotlin.Int, kotlin.String> origin=SAM_CONVERSION typeOperand=<root>.Fn<kotlin.Int, kotlin.String>
+          FUN_EXPR type=kotlin.Function3<kotlin.String, kotlin.Int, kotlin.Int, kotlin.String> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (s:kotlin.String, i:kotlin.Int, ti:kotlin.Int) returnType:kotlin.String
               VALUE_PARAMETER name:s index:0 type:kotlin.String
               VALUE_PARAMETER name:i index:1 type:kotlin.Int

compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.txt

@@ -94,7 +94,8 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
                       $this: GET_VAR '<this>: <root>.ProducerScope<kotlin.Any> declared in <root>.asFairChannel.<anonymous>' type=<root>.ProducerScope<kotlin.Any> origin=null
                 CALL 'public abstract fun collect (collector: <root>.FlowCollector<T of <root>.Flow>): kotlin.Unit [suspend] declared in <root>.Flow' type=kotlin.Unit origin=null
                   $this: GET_VAR 'flow: <root>.Flow<*> declared in <root>.asFairChannel' type=<root>.Flow<*> origin=null
-                  collector: FUN_EXPR type=kotlin.Function1<kotlin.Any?, kotlin.Unit> origin=LAMBDA
+                  collector: TYPE_OP type=<root>.FlowCollector<kotlin.Any?> origin=SAM_CONVERSION typeOperand=<root>.FlowCollector<kotlin.Any?>
+                    FUN_EXPR type=kotlin.Function1<kotlin.Any?, kotlin.Unit> origin=LAMBDA
                       FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (value:kotlin.Any?) returnType:kotlin.Unit
                         VALUE_PARAMETER name:value index:0 type:kotlin.Any?
                         BLOCK_BODY
@@ -128,7 +129,8 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
               BLOCK_BODY
                 CALL 'public abstract fun collect (collector: <root>.FlowCollector<T of <root>.Flow>): kotlin.Unit [suspend] declared in <root>.Flow' type=kotlin.Unit origin=null
                   $this: GET_VAR 'flow: <root>.Flow<*> declared in <root>.asChannel' type=<root>.Flow<*> origin=null
-                  collector: FUN_EXPR type=kotlin.Function1<kotlin.Any?, kotlin.Unit> origin=LAMBDA
+                  collector: TYPE_OP type=<root>.FlowCollector<kotlin.Any?> origin=SAM_CONVERSION typeOperand=<root>.FlowCollector<kotlin.Any?>
+                    FUN_EXPR type=kotlin.Function1<kotlin.Any?, kotlin.Unit> origin=LAMBDA
                       FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (value:kotlin.Any?) returnType:kotlin.Unit
                         VALUE_PARAMETER name:value index:0 type:kotlin.Any?
                         BLOCK_BODY