Initializer default values in 'tailrec' method in proper order

#KT-31540 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/TailRecursionCodegen.kt

@@ -16,17 +16,14 @@
 
 package org.jetbrains.kotlin.codegen
 
-import com.google.common.collect.Lists
-import org.jetbrains.kotlin.cfg.TailRecursionKind
 import org.jetbrains.kotlin.codegen.context.MethodContext
 import org.jetbrains.kotlin.codegen.coroutines.*
 import org.jetbrains.kotlin.codegen.state.GenerationState
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
-import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtSimpleNameExpression
-import org.jetbrains.kotlin.psi.ValueArgument
 import org.jetbrains.kotlin.resolve.calls.callUtil.*
 import org.jetbrains.kotlin.resolve.calls.model.*
 import org.jetbrains.org.objectweb.asm.Type
@@ -56,7 +53,7 @@ class TailRecursionCodegen(
         val arguments = resolvedCall.valueArgumentsByIndex ?: throw IllegalStateException("Failed to arrange value arguments by index: $fd")
 
         if (fd.isSuspend) {
-            AsmUtil.pop(v, callable.getValueParameters()[callable.getValueParameters().size - 1].asmType)
+            AsmUtil.pop(v, callable.getValueParameters().last().asmType)
         }
 
         assignParameterValues(fd, callable, arguments)
@@ -81,6 +78,9 @@ class TailRecursionCodegen(
         callableMethod: CallableMethod,
         valueArguments: List<ResolvedValueArgument>
     ) {
+        val properDefaultInitialization =
+            state.languageVersionSettings.supportsFeature(LanguageFeature.ProperComputationOrderOfTailrecDefaultParameters)
+
         val types = callableMethod.valueParameterTypes
         loop@ for (parameterDescriptor in fd.valueParameters.asReversed()) {
             val arg = valueArguments[parameterDescriptor.index]
@@ -102,7 +102,12 @@ class TailRecursionCodegen(
                 }
                 is DefaultValueArgument -> {
                     AsmUtil.pop(v, type)
-                    DefaultParameterValueLoader.DEFAULT.genValue(parameterDescriptor, codegen).put(type, v)
+                    if (properDefaultInitialization) {
+                        //Initialization in proper order is performed in loop below
+                        continue@loop
+                    } else {
+                        DefaultParameterValueLoader.DEFAULT.genValue(parameterDescriptor, codegen).put(type, v)
+                    }
                 }
                 is VarargValueArgument -> {
                     // assign the parameter below
@@ -112,6 +117,18 @@ class TailRecursionCodegen(
 
             store(parameterDescriptor, type)
         }
+
+        if (properDefaultInitialization) {
+            for (parameterDescriptor in fd.valueParameters) {
+                val arg = valueArguments[parameterDescriptor.index]
+                val type = types[parameterDescriptor.index]
+
+                if (arg is DefaultValueArgument) {
+                    DefaultParameterValueLoader.DEFAULT.genValue(parameterDescriptor, codegen).put(type, v)
+                    store(parameterDescriptor, type)
+                }
+            }
+        }
     }
 
     private fun store(parameterDescriptor: ValueParameterDescriptor, type: Type) {

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsSmokeTestGenerated.java

@@ -469,6 +469,11 @@ public class FirDiagnosticsSmokeTestGenerated extends AbstractFirDiagnosticsSmok
         runTest("compiler/testData/diagnostics/tests/ProjectionsInSupertypes.kt");
     }
 
+    @TestMetadata("properDefaultInitializationInTailrec.kt")
+    public void testProperDefaultInitializationInTailrec() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/properDefaultInitializationInTailrec.kt");
+    }
+
     @TestMetadata("Properties.kt")
     public void testProperties() throws Exception {
         runTest("compiler/testData/diagnostics/tests/Properties.kt");
@@ -689,6 +694,11 @@ public class FirDiagnosticsSmokeTestGenerated extends AbstractFirDiagnosticsSmok
         runTest("compiler/testData/diagnostics/tests/UnitValue.kt");
     }
 
+    @TestMetadata("unproperDefaultInitializationInTailrec.kt")
+    public void testUnproperDefaultInitializationInTailrec() throws Exception {
+        runTest("compiler/testData/diagnostics/tests/unproperDefaultInitializationInTailrec.kt");
+    }
+
     @TestMetadata("Unresolved.kt")
     public void testUnresolved() throws Exception {
         runTest("compiler/testData/diagnostics/tests/Unresolved.kt");

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/checkers/DefaultCheckerInTailrec.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve.jvm.checkers
+
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.psi.KtConstantExpression
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.KtParameter
+import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
+import org.jetbrains.kotlin.resolve.checkers.DeclarationChecker
+import org.jetbrains.kotlin.resolve.checkers.DeclarationCheckerContext
+import org.jetbrains.kotlin.resolve.constants.evaluate.ConstantExpressionEvaluator
+import org.jetbrains.kotlin.resolve.descriptorUtil.module
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
+import org.jetbrains.kotlin.resolve.jvm.getCompileTimeConstant
+import org.jetbrains.kotlin.types.typeUtil.isPrimitiveNumberOrNullableType
+
+object DefaultCheckerInTailrec : DeclarationChecker {
+    override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
+        if (declaration !is KtNamedFunction || descriptor !is FunctionDescriptor || !descriptor.isTailrec) return
+
+        if (context.languageVersionSettings.supportsFeature(LanguageFeature.ProperComputationOrderOfTailrecDefaultParameters)) return
+
+        val defaultValues = descriptor.valueParameters.filter { it.declaresDefaultValue() }.filter {
+            val parameterDeclaration = DescriptorToSourceUtils.descriptorToDeclaration(it)
+            if (parameterDeclaration is KtParameter) {
+                parameterDeclaration.defaultValue?.let {
+                    getCompileTimeConstant(
+                        it,
+                        context.trace.bindingContext,
+                        false,
+                        context.languageVersionSettings.supportsFeature(LanguageFeature.InlineConstVals)
+                    )?.let { const ->
+                        val type = const.getType(descriptor.module)
+                        return@filter !(KotlinBuiltIns.isPrimitiveTypeOrNullablePrimitiveType(type) ||
+                                KotlinBuiltIns.isStringOrNullableString(type))
+                    }
+                }
+            }
+
+            true
+        }
+
+        if (defaultValues.size > 1) {
+            context.trace.report(ErrorsJvm.TAILREC_WITH_DEFAULTS.on(declaration))
+        }
+    }
+}

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/DefaultErrorMessagesJvm.java

@@ -151,6 +151,7 @@ public class DefaultErrorMessagesJvm implements DefaultErrorMessages.Extension {
                 "See https://youtrack.jetbrains.com/issue/KT-18053 for more details";
         MAP.put(CONCURRENT_HASH_MAP_CONTAINS_OPERATOR, MESSAGE_FOR_CONCURRENT_HASH_MAP_CONTAINS);
         MAP.put(CONCURRENT_HASH_MAP_CONTAINS_OPERATOR_ERROR, MESSAGE_FOR_CONCURRENT_HASH_MAP_CONTAINS);
+        MAP.put(TAILREC_WITH_DEFAULTS, "Computation order of non-constant default arguments in tail-recursive functions will change in 1.4. See KT-31540 for more details");
     }
 
     @NotNull

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/ErrorsJvm.java

@@ -10,10 +10,7 @@ import org.jetbrains.kotlin.descriptors.CallableDescriptor;
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
 import org.jetbrains.kotlin.diagnostics.*;
 import org.jetbrains.kotlin.name.FqName;
-import org.jetbrains.kotlin.psi.KtAnnotationEntry;
-import org.jetbrains.kotlin.psi.KtDeclaration;
-import org.jetbrains.kotlin.psi.KtElement;
-import org.jetbrains.kotlin.psi.KtExpression;
+import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.types.KotlinType;
 
 import static org.jetbrains.kotlin.diagnostics.PositioningStrategies.*;
@@ -135,6 +132,8 @@ public interface ErrorsJvm {
     DiagnosticFactory0<PsiElement> CONCURRENT_HASH_MAP_CONTAINS_OPERATOR = DiagnosticFactory0.create(WARNING);
     DiagnosticFactory0<PsiElement> CONCURRENT_HASH_MAP_CONTAINS_OPERATOR_ERROR = DiagnosticFactory0.create(ERROR);
 
+    DiagnosticFactory0<KtNamedFunction> TAILREC_WITH_DEFAULTS = DiagnosticFactory0.create(WARNING, DECLARATION_SIGNATURE);
+
     @SuppressWarnings("UnusedDeclaration")
     Object _initializer = new Object() {
         {

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/platform/JvmPlatformConfigurator.kt

@@ -38,7 +38,8 @@ object JvmPlatformConfigurator : PlatformConfiguratorBase(
         JvmAnnotationsTargetNonExistentAccessorChecker(),
         BadInheritedJavaSignaturesChecker,
         JvmMultifileClassStateChecker,
-        SynchronizedOnInlineMethodChecker
+        SynchronizedOnInlineMethodChecker,
+        DefaultCheckerInTailrec
     ),
 
     additionalCallCheckers = listOf(

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects.kt

@@ -1,5 +1,5 @@
+// !LANGUAGE: +ProperComputationOrderOfTailrecDefaultParameters
 // DONT_RUN_GENERATED_CODE: JS
-// IGNORE_BACKEND: JVM
 
 var counter = 0
 fun inc() = counter++

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects2.kt

@@ -1,3 +1,5 @@
+// !LANGUAGE: +ProperComputationOrderOfTailrecDefaultParameters
+// Flag above doesn't matter cause 1 default value is passed explicitly in tail recursion call
 // DONT_RUN_GENERATED_CODE: JS
 
 var counter = 0

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.kt

@@ -0,0 +1,17 @@
+// !LANGUAGE: -ProperComputationOrderOfTailrecDefaultParameters
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND: JVM_IR
+
+var counter = 0
+fun calc(counter: Int) = if (counter % 2 == 0) "K" else "O"
+
+<!TAILREC_WITH_DEFAULTS!>tailrec fun test(x: Int, y: String = calc(counter++), z: String = calc(counter++)): String<!> {
+    if (x > 0)
+        return y + z
+
+    return test(x + 1)
+}
+
+fun box(): String {
+    return test(0)
+}

compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.txt

@@ -0,0 +1,6 @@
+package
+
+public var counter: kotlin.Int
+public fun box(): kotlin.String
+public fun calc(/*0*/ counter: kotlin.Int): kotlin.String
+public tailrec fun test(/*0*/ x: kotlin.Int, /*1*/ y: kotlin.String = ..., /*2*/ z: kotlin.String = ...): kotlin.String

compiler/testData/diagnostics/tests/properDefaultInitializationInTailrec.kt

@@ -0,0 +1,39 @@
+//!LANGUAGE: +ProperComputationOrderOfTailrecDefaultParameters
+import kotlin.reflect.KClass
+
+fun withEffects(): String = "OK"
+
+const val Z = "123"
+
+enum class EnumA {
+    A
+}
+
+tailrec fun foo(i: Int = 1, c: Char = '2', s: String = "1234", b: Boolean = true, d: Double = 1.0,  l: Long =  1L,  y: String = withEffects()) {
+    foo(i, c, s, b, d, l, y)
+}
+
+
+tailrec fun foo2(x: Int = 1, y: String = withEffects(), z: String = Z) {
+    foo2(x, y, z)
+}
+
+tailrec fun foo3(y: String = withEffects()) {
+    foo3(y)
+}
+
+tailrec fun foo4(x: String = withEffects(), y: String = withEffects()) {
+    foo4(x, y)
+}
+
+tailrec fun foo5(x: String = withEffects(), y: String = withEffects(), z: String = withEffects()) {
+    foo5(x, y, z)
+}
+
+tailrec fun foo6(x: String = withEffects(), y: EnumA = EnumA.A) {
+    foo6(x, y)
+}
+
+tailrec fun foo7(x: String = withEffects(), y: KClass<out EnumA> = EnumA.A::class) {
+    foo7(x, y)
+}

compiler/testData/diagnostics/tests/properDefaultInitializationInTailrec.txt

@@ -0,0 +1,30 @@
+package
+
+public const val Z: kotlin.String = "123"
+public tailrec fun foo(/*0*/ i: kotlin.Int = ..., /*1*/ c: kotlin.Char = ..., /*2*/ s: kotlin.String = ..., /*3*/ b: kotlin.Boolean = ..., /*4*/ d: kotlin.Double = ..., /*5*/ l: kotlin.Long = ..., /*6*/ y: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo2(/*0*/ x: kotlin.Int = ..., /*1*/ y: kotlin.String = ..., /*2*/ z: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo3(/*0*/ y: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo4(/*0*/ x: kotlin.String = ..., /*1*/ y: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo5(/*0*/ x: kotlin.String = ..., /*1*/ y: kotlin.String = ..., /*2*/ z: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo6(/*0*/ x: kotlin.String = ..., /*1*/ y: EnumA = ...): kotlin.Unit
+public tailrec fun foo7(/*0*/ x: kotlin.String = ..., /*1*/ y: kotlin.reflect.KClass<out EnumA> = ...): kotlin.Unit
+public fun withEffects(): kotlin.String
+
+public final enum class EnumA : kotlin.Enum<EnumA> {
+    enum entry A
+
+    private constructor EnumA()
+    public final override /*1*/ /*fake_override*/ val name: kotlin.String
+    public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
+    protected final override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: EnumA): kotlin.Int
+    public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    protected/*protected and package*/ final override /*1*/ /*fake_override*/ /*isHiddenForResolutionEverywhereBesideSupercalls*/ fun finalize(): kotlin.Unit
+    public final override /*1*/ /*fake_override*/ /*isHiddenForResolutionEverywhereBesideSupercalls*/ fun getDeclaringClass(): java.lang.Class<EnumA!>!
+    public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    // Static members
+    public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): EnumA
+    public final /*synthesized*/ fun values(): kotlin.Array<EnumA>
+}

compiler/testData/diagnostics/tests/unproperDefaultInitializationInTailrec.kt

@@ -0,0 +1,39 @@
+//!LANGUAGE: -ProperComputationOrderOfTailrecDefaultParameters
+
+import kotlin.reflect.KClass
+
+fun withEffects(): String = "OK"
+
+const val Z = "123"
+
+enum class EnumA {
+    A
+}
+
+tailrec fun foo(i: Int = 1, c: Char = '2', s: String = "1234", b: Boolean = true, d: Double = 1.0,  l: Long =  1L,  y: String = withEffects()) {
+    foo(i, c, s, b, d, l, y)
+}
+
+tailrec fun foo2(x: Int = 1, y: String = withEffects(), z: String = Z) {
+    foo2(x, y, z)
+}
+
+tailrec fun foo3(y: String = withEffects()) {
+    foo3(y)
+}
+
+<!TAILREC_WITH_DEFAULTS!>tailrec fun foo4(x: String = withEffects(), y: String = withEffects())<!> {
+    foo4(x, y)
+}
+
+<!TAILREC_WITH_DEFAULTS!>tailrec fun foo5(x: String = withEffects(), y: String = withEffects(), z: String = withEffects())<!> {
+    foo5(x, y, z)
+}
+
+<!TAILREC_WITH_DEFAULTS!>tailrec fun foo6(x: String = withEffects(), y: EnumA = EnumA.A)<!> {
+    foo6(x, y)
+}
+
+<!TAILREC_WITH_DEFAULTS!>tailrec fun foo7(x: String = withEffects(), y: KClass<out EnumA> = EnumA.A::class)<!> {
+    foo7(x, y)
+}

compiler/testData/diagnostics/tests/unproperDefaultInitializationInTailrec.txt

@@ -0,0 +1,30 @@
+package
+
+public const val Z: kotlin.String = "123"
+public tailrec fun foo(/*0*/ i: kotlin.Int = ..., /*1*/ c: kotlin.Char = ..., /*2*/ s: kotlin.String = ..., /*3*/ b: kotlin.Boolean = ..., /*4*/ d: kotlin.Double = ..., /*5*/ l: kotlin.Long = ..., /*6*/ y: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo2(/*0*/ x: kotlin.Int = ..., /*1*/ y: kotlin.String = ..., /*2*/ z: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo3(/*0*/ y: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo4(/*0*/ x: kotlin.String = ..., /*1*/ y: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo5(/*0*/ x: kotlin.String = ..., /*1*/ y: kotlin.String = ..., /*2*/ z: kotlin.String = ...): kotlin.Unit
+public tailrec fun foo6(/*0*/ x: kotlin.String = ..., /*1*/ y: EnumA = ...): kotlin.Unit
+public tailrec fun foo7(/*0*/ x: kotlin.String = ..., /*1*/ y: kotlin.reflect.KClass<out EnumA> = ...): kotlin.Unit
+public fun withEffects(): kotlin.String
+
+public final enum class EnumA : kotlin.Enum<EnumA> {
+    enum entry A
+
+    private constructor EnumA()
+    public final override /*1*/ /*fake_override*/ val name: kotlin.String
+    public final override /*1*/ /*fake_override*/ val ordinal: kotlin.Int
+    protected final override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: EnumA): kotlin.Int
+    public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    protected/*protected and package*/ final override /*1*/ /*fake_override*/ /*isHiddenForResolutionEverywhereBesideSupercalls*/ fun finalize(): kotlin.Unit
+    public final override /*1*/ /*fake_override*/ /*isHiddenForResolutionEverywhereBesideSupercalls*/ fun getDeclaringClass(): java.lang.Class<EnumA!>!
+    public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    // Static members
+    public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): EnumA
+    public final /*synthesized*/ fun values(): kotlin.Array<EnumA>
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -471,6 +471,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
             runTest("compiler/testData/diagnostics/tests/ProjectionsInSupertypes.kt");
         }
 
+        @TestMetadata("properDefaultInitializationInTailrec.kt")
+        public void testProperDefaultInitializationInTailrec() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/properDefaultInitializationInTailrec.kt");
+        }
+
         @TestMetadata("Properties.kt")
         public void testProperties() throws Exception {
             runTest("compiler/testData/diagnostics/tests/Properties.kt");
@@ -691,6 +696,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
             runTest("compiler/testData/diagnostics/tests/UnitValue.kt");
         }
 
+        @TestMetadata("unproperDefaultInitializationInTailrec.kt")
+        public void testUnproperDefaultInitializationInTailrec() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/unproperDefaultInitializationInTailrec.kt");
+        }
+
         @TestMetadata("Unresolved.kt")
         public void testUnresolved() throws Exception {
             runTest("compiler/testData/diagnostics/tests/Unresolved.kt");
@@ -24125,6 +24135,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects2.kt");
                 }
 
+                @TestMetadata("defaultArgsWithSideEffectsOld.kt")
+                public void testDefaultArgsWithSideEffectsOld() throws Exception {
+                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.kt");
+                }
+
                 @TestMetadata("extensionTailCall.kt")
                 public void testExtensionTailCall() throws Exception {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/extensionTailCall.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -471,6 +471,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
             runTest("compiler/testData/diagnostics/tests/ProjectionsInSupertypes.kt");
         }
 
+        @TestMetadata("properDefaultInitializationInTailrec.kt")
+        public void testProperDefaultInitializationInTailrec() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/properDefaultInitializationInTailrec.kt");
+        }
+
         @TestMetadata("Properties.kt")
         public void testProperties() throws Exception {
             runTest("compiler/testData/diagnostics/tests/Properties.kt");
@@ -691,6 +696,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
             runTest("compiler/testData/diagnostics/tests/UnitValue.kt");
         }
 
+        @TestMetadata("unproperDefaultInitializationInTailrec.kt")
+        public void testUnproperDefaultInitializationInTailrec() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/unproperDefaultInitializationInTailrec.kt");
+        }
+
         @TestMetadata("Unresolved.kt")
         public void testUnresolved() throws Exception {
             runTest("compiler/testData/diagnostics/tests/Unresolved.kt");
@@ -24045,6 +24055,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects2.kt");
                 }
 
+                @TestMetadata("defaultArgsWithSideEffectsOld.kt")
+                public void testDefaultArgsWithSideEffectsOld() throws Exception {
+                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.kt");
+                }
+
                 @TestMetadata("extensionTailCall.kt")
                 public void testExtensionTailCall() throws Exception {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/extensionTailCall.kt");

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

@@ -10056,6 +10056,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects2.kt");
                 }
 
+                @TestMetadata("defaultArgsWithSideEffectsOld.kt")
+                public void testDefaultArgsWithSideEffectsOld() throws Exception {
+                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.kt");
+                }
+
                 @TestMetadata("extensionTailCall.kt")
                 public void testExtensionTailCall() throws Exception {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/extensionTailCall.kt");

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

@@ -10023,11 +10023,6 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)
             public static class TailRecursion extends AbstractLightAnalysisModeTest {
-                @TestMetadata("defaultArgsWithSideEffects.kt")
-                public void ignoreDefaultArgsWithSideEffects() throws Exception {
-                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects.kt");
-                }
-
                 private void runTest(String testDataFilePath) throws Exception {
                     KotlinTestUtils.runTest(this::doTest, TargetBackend.JVM, testDataFilePath);
                 }
@@ -10051,11 +10046,21 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsOverridden.kt");
                 }
 
+                @TestMetadata("defaultArgsWithSideEffects.kt")
+                public void testDefaultArgsWithSideEffects() throws Exception {
+                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects.kt");
+                }
+
                 @TestMetadata("defaultArgsWithSideEffects2.kt")
                 public void testDefaultArgsWithSideEffects2() throws Exception {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects2.kt");
                 }
 
+                @TestMetadata("defaultArgsWithSideEffectsOld.kt")
+                public void testDefaultArgsWithSideEffectsOld() throws Exception {
+                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.kt");
+                }
+
                 @TestMetadata("extensionTailCall.kt")
                 public void testExtensionTailCall() throws Exception {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/extensionTailCall.kt");

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

@@ -8941,6 +8941,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffects2.kt");
                 }
 
+                @TestMetadata("defaultArgsWithSideEffectsOld.kt")
+                public void testDefaultArgsWithSideEffectsOld() throws Exception {
+                    runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/defaultArgsWithSideEffectsOld.kt");
+                }
+
                 @TestMetadata("extensionTailCall.kt")
                 public void testExtensionTailCall() throws Exception {
                     runTest("compiler/testData/codegen/box/diagnostics/functions/tailRecursion/extensionTailCall.kt");

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -109,6 +109,7 @@ enum class LanguageFeature(
     AllowBreakAndContinueInsideWhen(KOTLIN_1_4),
     MixedNamedArgumentsInTheirOwnPosition(KOTLIN_1_4),
     ProhibitTailrecOnVirtualMember(KOTLIN_1_4, kind = BUG_FIX),
+    ProperComputationOrderOfTailrecDefaultParameters(KOTLIN_1_4),
 
     ProperVisibilityForCompanionObjectInstanceField(sinceVersion = null, kind = BUG_FIX),
     // Temporarily disabled, see KT-27084/KT-22379