JVM: move descriptors from DefaultLambda to PsiDefaultLambda

Also, produce more correct results in IrDefaultLambda's
`invokeMethodParameters` and `invokeMethodReturnType`. This affects
whether the inliner inserts inline class boxings/unboxings around lambda
calls; while this doesn't matter now due to KT-46601, it would if the
naming was fixed.

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/LambdaInfo.kt

@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.codegen.inline
 
 import org.jetbrains.kotlin.codegen.AsmUtil
 import org.jetbrains.kotlin.codegen.context.EnclosedValueDescriptor
-import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.resolve.jvm.AsmTypes.*
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.util.OperatorNameConventions
@@ -101,14 +100,6 @@ abstract class DefaultLambda(
     final override lateinit var invokeMethod: Method
         private set
 
-    private lateinit var invokeMethodDescriptor: FunctionDescriptor
-
-    override val invokeMethodParameters: List<KotlinType?>
-        get() = invokeMethodDescriptor.valueParameters.map { it.returnType }
-
-    override val invokeMethodReturnType: KotlinType?
-        get() = invokeMethodDescriptor.returnType
-
     final override lateinit var capturedVars: List<CapturedParamDesc>
         private set
 
@@ -123,10 +114,10 @@ abstract class DefaultLambda(
         val isPropertyReference = superName in PROPERTY_REFERENCE_SUPER_CLASSES
         val isFunctionReference = superName == FUNCTION_REFERENCE.internalName || superName == FUNCTION_REFERENCE_IMPL.internalName
 
-        val descriptor = Type.getMethodDescriptor(Type.VOID_TYPE, *capturedArgs)
-        val constructor = getMethodNode(classBytes, "<init>", descriptor, lambdaClassType)?.node
+        val constructorDescriptor = Type.getMethodDescriptor(Type.VOID_TYPE, *capturedArgs)
+        val constructor = getMethodNode(classBytes, "<init>", constructorDescriptor, lambdaClassType)?.node
         assert(constructor != null || capturedArgs.isEmpty()) {
-            "Can't find non-default constructor <init>$descriptor for default lambda $lambdaClassType"
+            "Can't find non-default constructor <init>$constructorDescriptor for default lambda $lambdaClassType"
         }
         capturedVars =
             if (isFunctionReference || isPropertyReference)
@@ -140,11 +131,12 @@ abstract class DefaultLambda(
                 }?.toList() ?: emptyList()
         isBoundCallableReference = (isFunctionReference || isPropertyReference) && capturedVars.isNotEmpty()
 
-        invokeMethodDescriptor = findInvokeMethodDescriptor(isPropertyReference)
-        val methodName = (if (isPropertyReference) OperatorNameConventions.GET else OperatorNameConventions.INVOKE).asString()
-        val signature = mapAsmSignature(sourceCompiler, invokeMethodDescriptor)
-        node = getMethodNode(classBytes, methodName, signature.descriptor, lambdaClassType, signatureAmbiguity = true)
-            ?: error("Can't find method '$signature' in '${lambdaClassType.internalName}'")
+        val invokeName = (if (isPropertyReference) OperatorNameConventions.GET else OperatorNameConventions.INVOKE).asString()
+        val invokeDescriptor = mapAsmDescriptor(sourceCompiler, isPropertyReference)
+        // TODO: `signatureAmbiguity = true` ignores the argument types from `invokeDescriptor` and only looks at the count.
+        //   This effectively masks incorrect results from `mapAsmDescriptor`, which hopefully won't manifest in another way.
+        node = getMethodNode(classBytes, invokeName, invokeDescriptor, lambdaClassType, signatureAmbiguity = true)
+            ?: error("Can't find method '$invokeName$invokeDescriptor' in '${lambdaClassType.internalName}'")
         invokeMethod = Method(node.node.name, node.node.desc)
         if (needReification) {
             //nested classes could also require reification
@@ -152,10 +144,7 @@ abstract class DefaultLambda(
         }
     }
 
-    protected abstract fun mapAsmSignature(sourceCompiler: SourceCompilerForInline, descriptor: FunctionDescriptor): Method
-
-    // TODO: get rid of this; descriptors should *only* be used by PsiDefaultLambda
-    protected abstract fun findInvokeMethodDescriptor(isPropertyReference: Boolean): FunctionDescriptor
+    protected abstract fun mapAsmDescriptor(sourceCompiler: SourceCompilerForInline, isPropertyReference: Boolean): String
 
     private companion object {
         val PROPERTY_REFERENCE_SUPER_CLASSES =

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/PsiInlineCodegen.kt

@@ -343,14 +343,22 @@ class PsiDefaultLambda(
     offset: Int,
     needReification: Boolean
 ) : DefaultLambda(capturedArgs, parameterDescriptor.isCrossinline, offset, needReification) {
-    override fun mapAsmSignature(sourceCompiler: SourceCompilerForInline, descriptor: FunctionDescriptor): Method =
-        sourceCompiler.state.typeMapper.mapSignatureSkipGeneric(descriptor).asmMethod
+    private lateinit var invokeMethodDescriptor: FunctionDescriptor
 
-    override fun findInvokeMethodDescriptor(isPropertyReference: Boolean): FunctionDescriptor =
-        parameterDescriptor.type.memberScope
+    override val invokeMethodParameters: List<KotlinType?>
+        get() = invokeMethodDescriptor.explicitParameters.map { it.returnType }
+
+    override val invokeMethodReturnType: KotlinType?
+        get() = invokeMethodDescriptor.returnType
+
+    override fun mapAsmDescriptor(sourceCompiler: SourceCompilerForInline, isPropertyReference: Boolean): String {
+        invokeMethodDescriptor = parameterDescriptor.type.memberScope
             .getContributedFunctions(OperatorNameConventions.INVOKE, NoLookupLocation.FROM_BACKEND)
             .single().let {
-                // property reference generates erased 'get' method
+                // Property references only have an erased `get` method, while function references and lambdas
+                // have a non-erased `invoke` with an erased synthetic bridge, and we want to inline the former.
                 if (isPropertyReference) it.original else it
             }
+        return sourceCompiler.state.typeMapper.mapSignatureSkipGeneric(invokeMethodDescriptor).asmMethod.descriptor
+    }
 }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/IrInlineCodegen.kt

@@ -14,17 +14,16 @@ import org.jetbrains.kotlin.codegen.ValueKind
 import org.jetbrains.kotlin.codegen.inline.*
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
-import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.descriptors.*
 import org.jetbrains.kotlin.ir.expressions.*
+import org.jetbrains.kotlin.ir.types.IrSimpleType
 import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.types.classOrNull
+import org.jetbrains.kotlin.ir.types.IrTypeProjection
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.resolve.jvm.AsmTypes
 import org.jetbrains.kotlin.resolve.jvm.jvmSignature.JvmMethodSignature
 import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.org.objectweb.asm.Type
 import org.jetbrains.org.objectweb.asm.commons.Method
 import org.jetbrains.org.objectweb.asm.tree.MethodNode
@@ -234,18 +233,33 @@ class IrExpressionLambdaImpl(
 class IrDefaultLambda(
     override val lambdaClassType: Type,
     capturedArgs: Array<Type>,
-    irValueParameter: IrValueParameter,
+    private val irValueParameter: IrValueParameter,
     offset: Int,
     needReification: Boolean
 ) : DefaultLambda(capturedArgs, irValueParameter.isCrossinline, offset, needReification) {
-    // TODO: this always produces an erased signature, but it should be non-erased if this isn't a property reference
-    private val invoke = irValueParameter.type.classOrNull!!.owner.functions.single { it.name == OperatorNameConventions.INVOKE }
+    private lateinit var typeArguments: List<IrType>
 
-    override fun mapAsmSignature(sourceCompiler: SourceCompilerForInline, descriptor: FunctionDescriptor): Method =
-        (sourceCompiler as IrSourceCompilerForInline).codegen.context.methodSignatureMapper.mapSignatureSkipGeneric(invoke).asmMethod
+    override val invokeMethodParameters: List<KotlinType>
+        get() = typeArguments.dropLast(1).map { it.toIrBasedKotlinType() }
 
-    override fun findInvokeMethodDescriptor(isPropertyReference: Boolean): FunctionDescriptor =
-        invoke.toIrBasedDescriptor()
+    override val invokeMethodReturnType: KotlinType
+        get() = typeArguments.last().toIrBasedKotlinType()
+
+    override fun mapAsmDescriptor(sourceCompiler: SourceCompilerForInline, isPropertyReference: Boolean): String {
+        val context = (sourceCompiler as IrSourceCompilerForInline).codegen.context
+        typeArguments = (irValueParameter.type as IrSimpleType).arguments.let {
+            // Property references only have an erased `get` method, while function references and lambdas
+            // have a non-erased `invoke` with an erased synthetic bridge, and we want to inline the former.
+            if (isPropertyReference) {
+                List(it.size) { context.irBuiltIns.anyNType }
+            } else {
+                it.map { argument -> (argument as IrTypeProjection).type }
+            }
+        }
+        // TODO: while technically only the number of arguments here matters right now (see DefaultLambdaInfo.generateLambdaBody),
+        //       it would be better to map to a non-erased signature if not a property reference.
+        return Type.getMethodDescriptor(AsmTypes.OBJECT_TYPE, *Array(typeArguments.size - 1) { AsmTypes.OBJECT_TYPE })
+    }
 }
 
 fun IrExpression.isInlineIrExpression() =