JVM_IR: support function references with default parameters

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt

@@ -231,7 +231,8 @@ private fun IrTypeParameter.copySuperTypesFrom(source: IrTypeParameter) {
 fun IrFunction.copyValueParametersToStatic(
     source: IrFunction,
     origin: IrDeclarationOrigin,
-    dispatchReceiverType: IrType? = source.dispatchReceiverParameter?.type
+    dispatchReceiverType: IrType? = source.dispatchReceiverParameter?.type,
+    numValueParametersToCopy: Int = source.valueParameters.size
 ) {
     val target = this
     assert(target.valueParameters.isEmpty())
@@ -266,6 +267,7 @@ fun IrFunction.copyValueParametersToStatic(
     }
 
     for (oldValueParameter in source.valueParameters) {
+        if (oldValueParameter.index >= numValueParametersToCopy) break
         target.valueParameters.add(
             oldValueParameter.copyTo(
                 target,

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/JvmLower.kt

@@ -141,7 +141,7 @@ private val defaultArgumentInjectorPhase = makeIrFilePhase(
     ::JvmDefaultParameterInjector,
     name = "DefaultParameterInjector",
     description = "Transform calls with default arguments into calls to stubs",
-    prerequisite = setOf(defaultArgumentStubPhase, callableReferencePhase)
+    prerequisite = setOf(defaultArgumentStubPhase, callableReferencePhase, inlineCallableReferenceToLambdaPhase)
 )
 
 private val interfacePhase = makeIrFilePhase(

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/InlineCallableReferenceToLambda.kt

@@ -27,8 +27,11 @@ import org.jetbrains.kotlin.ir.builders.declarations.buildFun
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.IrFunctionReferenceImpl
-import org.jetbrains.kotlin.ir.util.defaultType
+import org.jetbrains.kotlin.ir.types.IrSimpleType
-import org.jetbrains.kotlin.ir.util.parentAsClass
+import org.jetbrains.kotlin.ir.types.classOrNull
+import org.jetbrains.kotlin.ir.types.isSubtypeOf
+import org.jetbrains.kotlin.ir.types.isSubtypeOfClass
+import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.name.Name
 
@@ -141,7 +144,24 @@ internal class InlineCallableReferenceToLambdaPhase(val context: JvmBackendConte
         val irBuilder =
             context.createIrBuilder(scope.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset)
 
+
         val boundReceiver = expression.dispatchReceiver ?: expression.extensionReceiver
+
+        val expectedType = expression.type
+        var expectedNumValueParameters: Int
+        if (expectedType.isFunctionOrKFunction() || expectedType.isSuspendFunction() || expectedType.isKSuspendFunction()) { // TODO: handle subtypes
+            expectedNumValueParameters = (expectedType as IrSimpleType).arguments.size - 1  // In ...Function classes, the last argument is return type
+            referencedFunction.dispatchReceiverParameter?.let { expectedNumValueParameters-- }
+            referencedFunction.extensionReceiverParameter?.let { expectedNumValueParameters-- }
+            boundReceiver?.let { expectedNumValueParameters++ }
+            assert(referencedFunction.valueParameters.subList(expectedNumValueParameters, referencedFunction.valueParameters.size).all {
+                it.defaultValue != null
+            })
+        } else {
+            assert(expectedType.classOrNull?.isSubtypeOfClass(context.irBuiltIns.kPropertyClass) == true)
+            expectedNumValueParameters = 0
+        }
+
         return irBuilder.irBlock(expression, IrStatementOrigin.LAMBDA) {
             lateinit var variableForBoundReceiver: IrVariable
             if (boundReceiver != null) {
@@ -161,9 +181,10 @@ internal class InlineCallableReferenceToLambdaPhase(val context: JvmBackendConte
                 }
                 copyTypeParametersFrom(referencedFunction)
                 if (boundReceiver == null) {
-                    copyValueParametersToStatic(referencedFunction, origin)
+                    copyValueParametersToStatic(referencedFunction, origin, numValueParametersToCopy = expectedNumValueParameters)
                 } else {
                     for (oldValueParameter in referencedFunction.valueParameters) {
+                        if (oldValueParameter.index >= expectedNumValueParameters) break
                         valueParameters.add(
                             oldValueParameter.copyTo(
                                 this,
@@ -197,6 +218,7 @@ internal class InlineCallableReferenceToLambdaPhase(val context: JvmBackendConte
                             }
 
                             for (it in referencedFunction.valueParameters.indices) {
+                                if (it >= expectedNumValueParameters) break
                                 call.putValueArgument(it, irGet(valueParameters[shift++]))
                             }
                         }

compiler/testData/codegen/box/defaultArguments/referenceAsArg.kt

@@ -0,0 +1,8 @@
+// !LANGUAGE: +NewInference +FunctionReferenceWithDefaultValueAsOtherType
+// IGNORE_BACKEND: JS_IR
+
+inline fun String.app(f: (String) -> String) = f(this)
+
+fun fff(s: String, n: Int = 42) = s
+
+fun box() = "OK".app(::fff)

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -8982,6 +8982,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/defaultArguments/protected.kt");
         }
 
+        @TestMetadata("referenceAsArg.kt")
+        public void testReferenceAsArg() throws Exception {
+            runTest("compiler/testData/codegen/box/defaultArguments/referenceAsArg.kt");
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             runTest("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -8982,6 +8982,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/defaultArguments/protected.kt");
         }
 
+        @TestMetadata("referenceAsArg.kt")
+        public void testReferenceAsArg() throws Exception {
+            runTest("compiler/testData/codegen/box/defaultArguments/referenceAsArg.kt");
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             runTest("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -7867,6 +7867,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/defaultArguments/protected.kt");
         }
 
+        @TestMetadata("referenceAsArg.kt")
+        public void testReferenceAsArg() throws Exception {
+            runTest("compiler/testData/codegen/box/defaultArguments/referenceAsArg.kt");
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             runTest("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -6717,6 +6717,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/defaultArguments/protected.kt");
         }
 
+        @TestMetadata("referenceAsArg.kt")
+        public void testReferenceAsArg() throws Exception {
+            runTest("compiler/testData/codegen/box/defaultArguments/referenceAsArg.kt");
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             runTest("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -7802,6 +7802,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/defaultArguments/protected.kt");
         }
 
+        @TestMetadata("referenceAsArg.kt")
+        public void testReferenceAsArg() throws Exception {
+            runTest("compiler/testData/codegen/box/defaultArguments/referenceAsArg.kt");
+        }
+
         @TestMetadata("simpleFromOtherFile.kt")
         public void testSimpleFromOtherFile() throws Exception {
             runTest("compiler/testData/codegen/box/defaultArguments/simpleFromOtherFile.kt");