[FIR] Don't copy VP default values for fake overrides

In general, overrides should not
contain default values, and it's
better to make fake overrides be close
to proper overrides as much as
possible. It will be important when
we begin running `FirOverrideChecker`
for fake overrides.

^KT-63879 Fixed
^KT-65534

compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirFakeOverrideGenerator.kt

@@ -135,7 +135,8 @@ object FirFakeOverrideGenerator {
         attributes = baseFunction.attributes.copy()
         typeParameters += configureAnnotationsTypeParametersAndSignature(
             session, baseFunction, newParameterTypes, newTypeParameters,
-            newReceiverType, newContextReceiverTypes, newReturnType, deferredReturnTypeCalculation, newSymbol
+            newReceiverType, newContextReceiverTypes, newReturnType, deferredReturnTypeCalculation, newSymbol,
+            copyDefaultValues = false,
         ).filterIsInstance<FirTypeParameter>()
         deprecationsProvider = baseFunction.deprecationsProvider
     }.apply {
@@ -181,7 +182,13 @@ object FirFakeOverrideGenerator {
             newContextReceiverTypes,
             newReturnType,
             deferredReturnTypeCalculation,
-            fakeOverrideSymbol
+            fakeOverrideSymbol,
+            // Copying default values here is important, because constructors don't
+            // override anything and we rely on this fact when mapping arguments
+            // during resolution.
+            // See: FirDefaultParametersResolver.declaresDefaultValue()
+            // See: testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/constructor-declaration/p-5/pos/3.4.kt
+            copyDefaultValues = true,
         )
 
         dispatchReceiverType = newDispatchReceiverType
@@ -204,6 +211,7 @@ object FirFakeOverrideGenerator {
         newReturnType: ConeKotlinType?,
         deferredReturnTypeCalculation: CallableCopyDeferredReturnTypeCalculation?,
         symbolForOverride: FirFunctionSymbol<*>,
+        copyDefaultValues: Boolean = false,
     ): List<FirTypeParameterRef> {
         return when {
             baseFunction.typeParameters.isEmpty() -> {
@@ -216,6 +224,7 @@ object FirFakeOverrideGenerator {
                     newReturnType,
                     deferredReturnTypeCalculation,
                     origin,
+                    copyDefaultValues,
                 )
                 emptyList()
             }
@@ -243,6 +252,7 @@ object FirFakeOverrideGenerator {
                     copiedReturnType,
                     newCallableCopySubstitutionForTypeUpdater,
                     origin,
+                    copyDefaultValues,
                 )
                 copiedTypeParameters
             }
@@ -256,6 +266,7 @@ object FirFakeOverrideGenerator {
                     newReturnType,
                     deferredReturnTypeCalculation,
                     origin,
+                    copyDefaultValues,
                 )
                 newTypeParameters
             }
@@ -271,6 +282,7 @@ object FirFakeOverrideGenerator {
         newReturnType: ConeKotlinType?,
         deferredTypeCalculation: CallableCopyDeferredReturnTypeCalculation?,
         origin: FirDeclarationOrigin,
+        copyDefaultValues: Boolean = false,
     ) {
         checkStatusIsResolved(baseFunction)
         annotations += baseFunction.annotations
@@ -304,7 +316,8 @@ object FirFakeOverrideGenerator {
                 valueParameter.returnTypeRef.withReplacedConeType(newType),
                 origin,
                 fakeFunctionSymbol,
-                this@configureAnnotationsAndSignature.source ?: valueParameter.source
+                this@configureAnnotationsAndSignature.source ?: valueParameter.source,
+                copyDefaultValues,
             )
         }
 
@@ -322,18 +335,21 @@ object FirFakeOverrideGenerator {
         returnTypeRef: FirTypeRef,
         origin: FirDeclarationOrigin,
         containingFunctionSymbol: FirFunctionSymbol<*>,
-        source: KtSourceElement?
+        source: KtSourceElement?,
+        copyDefaultValues: Boolean = true,
     ): FirValueParameter = buildValueParameterCopy(original) {
         this.origin = origin
         this.source = source
         this.returnTypeRef = returnTypeRef
         symbol = FirValueParameterSymbol(original.name)
         this.containingFunctionSymbol = containingFunctionSymbol
-        defaultValue = defaultValue?.let {
-            buildExpressionStub {
-                coneTypeOrNull = returnTypeRef.coneTypeOrNull
+        defaultValue = defaultValue
+            ?.takeIf { copyDefaultValues }
+            ?.let {
+                buildExpressionStub {
+                    coneTypeOrNull = returnTypeRef.coneTypeOrNull
+                }
             }
-        }
 
         resolvePhase = origin.resolvePhaseForCopy
     }