[FIR] Implement DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE diagnostic

#KT-59409 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -2868,6 +2868,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE) { firDiagnostic ->
+        DefaultValueNotAllowedInOverrideImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.FUN_INTERFACE_CONSTRUCTOR_REFERENCE) { firDiagnostic ->
         FunInterfaceConstructorReferenceImpl(
             firDiagnostic as KtPsiDiagnostic,

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -2032,6 +2032,10 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = DataObjectCustomEqualsOrHashCode::class
     }
 
+    interface DefaultValueNotAllowedInOverride : KtFirDiagnostic<KtElement> {
+        override val diagnosticClass get() = DefaultValueNotAllowedInOverride::class
+    }
+
     interface FunInterfaceConstructorReference : KtFirDiagnostic<KtExpression> {
         override val diagnosticClass get() = FunInterfaceConstructorReference::class
     }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -2439,6 +2439,11 @@ internal class DataObjectCustomEqualsOrHashCodeImpl(
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtNamedFunction>(firDiagnostic, token), KtFirDiagnostic.DataObjectCustomEqualsOrHashCode
 
+internal class DefaultValueNotAllowedInOverrideImpl(
+    firDiagnostic: KtPsiDiagnostic,
+    token: KtLifetimeToken,
+) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.DefaultValueNotAllowedInOverride
+
 internal class FunInterfaceConstructorReferenceImpl(
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -1009,6 +1009,10 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val DATA_OBJECT_CUSTOM_EQUALS_OR_HASH_CODE by error<KtNamedFunction>(PositioningStrategy.OVERRIDE_MODIFIER)
     }
 
+    val PARAMETER_DEFAULT_VALUES by object : DiagnosticGroup("Parameter default values") {
+        val DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE by error<KtElement>()
+    }
+
     val FUN_INTERFACES by object : DiagnosticGroup("Fun interfaces") {
         val FUN_INTERFACE_CONSTRUCTOR_REFERENCE by error<KtExpression>(PositioningStrategy.REFERENCE_BY_QUALIFIED)
         val FUN_INTERFACE_WRONG_COUNT_OF_ABSTRACT_MEMBERS by error<KtClass>(PositioningStrategy.FUN_MODIFIER)

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -527,6 +527,9 @@ object FirErrors {
     val TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED by warning0<PsiElement>(SourceElementPositioningStrategies.REFERENCED_NAME_BY_QUALIFIED)
     val DATA_OBJECT_CUSTOM_EQUALS_OR_HASH_CODE by error0<KtNamedFunction>(SourceElementPositioningStrategies.OVERRIDE_MODIFIER)
 
+    // Parameter default values
+    val DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE by error0<KtElement>()
+
     // Fun interfaces
     val FUN_INTERFACE_CONSTRUCTOR_REFERENCE by error0<KtExpression>(SourceElementPositioningStrategies.REFERENCE_BY_QUALIFIED)
     val FUN_INTERFACE_WRONG_COUNT_OF_ABSTRACT_MEMBERS by error0<KtClass>(SourceElementPositioningStrategies.FUN_MODIFIER)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirOverrideChecker.kt

@@ -217,6 +217,19 @@ object FirOverrideChecker : FirClassChecker() {
         return null
     }
 
+    @OptIn(SymbolInternals::class)
+    private fun FirFunctionSymbol<*>.checkDefaultValues(
+        reporter: DiagnosticReporter,
+        context: CheckerContext,
+    ) {
+        for (valueParameterSymbol in valueParameterSymbols) {
+            val defaultValue = valueParameterSymbol.fir.defaultValue
+            if (defaultValue != null) {
+                reporter.reportOn(defaultValue.source, FirErrors.DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE, context)
+            }
+        }
+    }
+
     private fun checkMember(
         member: FirCallableSymbol<*>,
         containingClass: FirClass,
@@ -299,6 +312,10 @@ object FirOverrideChecker : FirClassChecker() {
 
         member.checkDeprecation(reporter, overriddenMemberSymbols, context)
 
+        if (member is FirFunctionSymbol) {
+            member.checkDefaultValues(reporter, context)
+        }
+
         val restriction = member.checkReturnType(
             overriddenSymbols = overriddenMemberSymbols,
             typeCheckerState = typeCheckerState,

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrorsDefaultMessages.kt

@@ -153,6 +153,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DATA_CLASS_WITHOU
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DATA_OBJECT_CUSTOM_EQUALS_OR_HASH_CODE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DECLARATION_CANT_BE_INLINED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEFAULT_ARGUMENTS_IN_EXPECT_WITH_ACTUAL_TYPEALIAS
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DEFINITELY_NON_NULLABLE_AS_REIFIED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATED_MEMBER_HIDES_SUPERTYPE_OVERRIDE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.DELEGATED_PROPERTY_INSIDE_VALUE_CLASS
@@ -1643,6 +1644,9 @@ object FirErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
         map.put(TAIL_RECURSION_IN_TRY_IS_NOT_SUPPORTED, "Tail recursion optimization inside try/catch/finally is not supported")
         map.put(DATA_OBJECT_CUSTOM_EQUALS_OR_HASH_CODE, "Data object cannot have a custom implementation of 'equals' or 'hashCode'")
 
+        // Parameter default values
+        map.put(DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE, "An overriding function is not allowed to specify default values for its parameters.")
+
         // Fun interfaces
         map.put(FUN_INTERFACE_CONSTRUCTOR_REFERENCE, "Functional/SAM interface constructor references are prohibited")
 

compiler/testData/diagnostics/tests/dataClasses/dataClassExplicitlyOverridingCopyWithDefaults.fir.kt

@@ -5,5 +5,5 @@ interface WithCopy<T> {
 }
 
 data class Test(val str: String) : WithCopy<String> {
-    override fun copy(str: String = this.str) = Test(str)
+    override fun copy(str: String = <!DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE!>this.str<!>) = Test(str)
-}
+}

compiler/testData/diagnostics/tests/multiplatform/defaultArguments/expectedInheritsDefaultArguments.fir.kt

@@ -1,36 +0,0 @@
-// MODULE: m1-common
-// FILE: common.kt
-
-interface Foo {
-    fun ok(x: Int, y: String = "")
-
-    fun failX(x: Int, y: String = "")
-
-    fun failY(x: Int, y: String = "")
-}
-
-expect class Bar : Foo {
-    override fun ok(x: Int, y: String)
-
-    override fun failX(x: Int, y: String)
-
-    override fun failY(x: Int, y: String)
-}
-
-fun test(foo: Foo, bar: Bar) {
-    foo.ok(42)
-    foo.ok(42, "OK")
-    bar.ok(42)
-    bar.ok(42, "OK")
-}
-
-// MODULE: m2-jvm()()(m1-common)
-// FILE: jvm.kt
-
-actual class Bar : Foo {
-    actual override fun ok(x: Int, y: String) {}
-
-    actual override fun failX(<!ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS!>x: Int = 0<!>, y: String) {}
-
-    actual override fun failY(x: Int, <!ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS!>y: String = ""<!>) {}
-}

compiler/testData/diagnostics/tests/multiplatform/defaultArguments/expectedInheritsDefaultArguments.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // MODULE: m1-common
 // FILE: common.kt
 

compiler/testData/diagnostics/tests/override/DefaultParameterValueInOverride.fir.kt

@@ -1,13 +0,0 @@
-open class A {
-    open fun foo(a : Int) {}
-}
-
-class C : A() {
-    override fun foo(a : Int = 1) {
-    }
-}
-
-class D : A() {
-    override fun foo(a : Int = 1) {
-    }
-}

compiler/testData/diagnostics/tests/override/DefaultParameterValueInOverride.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 open class A {
     open fun foo(a : Int) {}
 }