[FIR] Improve the messages of the multiple defaults diagnostics

Mention the base functions where the default
values come from.

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

@@ -2619,42 +2619,66 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
     }
     add(FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES) { firDiagnostic ->
         MultipleDefaultsInheritedFromSupertypesImpl(
-            firSymbolBuilder.buildSymbol(firDiagnostic.a),
+            firDiagnostic.a,
+            firSymbolBuilder.buildSymbol(firDiagnostic.b),
+            firDiagnostic.c.map { firCallableSymbol ->
+                firSymbolBuilder.callableBuilder.buildCallableSymbol(firCallableSymbol)
+            },
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
     }
     add(FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE) { firDiagnostic ->
         MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideImpl(
-            firSymbolBuilder.buildSymbol(firDiagnostic.a),
+            firDiagnostic.a,
+            firSymbolBuilder.buildSymbol(firDiagnostic.b),
+            firDiagnostic.c.map { firCallableSymbol ->
+                firSymbolBuilder.callableBuilder.buildCallableSymbol(firCallableSymbol)
+            },
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
     }
     add(FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION.errorFactory) { firDiagnostic ->
         MultipleDefaultsInheritedFromSupertypesDeprecationErrorImpl(
-            firSymbolBuilder.buildSymbol(firDiagnostic.a),
+            firDiagnostic.a,
+            firSymbolBuilder.buildSymbol(firDiagnostic.b),
+            firDiagnostic.c.map { firCallableSymbol ->
+                firSymbolBuilder.callableBuilder.buildCallableSymbol(firCallableSymbol)
+            },
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
     }
     add(FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION.warningFactory) { firDiagnostic ->
         MultipleDefaultsInheritedFromSupertypesDeprecationWarningImpl(
-            firSymbolBuilder.buildSymbol(firDiagnostic.a),
+            firDiagnostic.a,
+            firSymbolBuilder.buildSymbol(firDiagnostic.b),
+            firDiagnostic.c.map { firCallableSymbol ->
+                firSymbolBuilder.callableBuilder.buildCallableSymbol(firCallableSymbol)
+            },
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
     }
     add(FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION.errorFactory) { firDiagnostic ->
         MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationErrorImpl(
-            firSymbolBuilder.buildSymbol(firDiagnostic.a),
+            firDiagnostic.a,
+            firSymbolBuilder.buildSymbol(firDiagnostic.b),
+            firDiagnostic.c.map { firCallableSymbol ->
+                firSymbolBuilder.callableBuilder.buildCallableSymbol(firCallableSymbol)
+            },
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
     }
     add(FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION.warningFactory) { firDiagnostic ->
         MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationWarningImpl(
-            firSymbolBuilder.buildSymbol(firDiagnostic.a),
+            firDiagnostic.a,
+            firSymbolBuilder.buildSymbol(firDiagnostic.b),
+            firDiagnostic.c.map { firCallableSymbol ->
+                firSymbolBuilder.callableBuilder.buildCallableSymbol(firCallableSymbol)
+            },
             firDiagnostic as KtPsiDiagnostic,
             token,
         )

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

@@ -1861,32 +1861,44 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
 
     interface MultipleDefaultsInheritedFromSupertypes : KtFirDiagnostic<KtElement> {
         override val diagnosticClass get() = MultipleDefaultsInheritedFromSupertypes::class
+        val name: Name
         val valueParameter: KtSymbol
+        val baseFunctions: List<KtCallableSymbol>
     }
 
     interface MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverride : KtFirDiagnostic<KtElement> {
         override val diagnosticClass get() = MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverride::class
+        val name: Name
         val valueParameter: KtSymbol
+        val baseFunctions: List<KtCallableSymbol>
     }
 
     interface MultipleDefaultsInheritedFromSupertypesDeprecationError : KtFirDiagnostic<KtElement> {
         override val diagnosticClass get() = MultipleDefaultsInheritedFromSupertypesDeprecationError::class
+        val name: Name
         val valueParameter: KtSymbol
+        val baseFunctions: List<KtCallableSymbol>
     }
 
     interface MultipleDefaultsInheritedFromSupertypesDeprecationWarning : KtFirDiagnostic<KtElement> {
         override val diagnosticClass get() = MultipleDefaultsInheritedFromSupertypesDeprecationWarning::class
+        val name: Name
         val valueParameter: KtSymbol
+        val baseFunctions: List<KtCallableSymbol>
     }
 
     interface MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationError : KtFirDiagnostic<KtElement> {
         override val diagnosticClass get() = MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationError::class
+        val name: Name
         val valueParameter: KtSymbol
+        val baseFunctions: List<KtCallableSymbol>
     }
 
     interface MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationWarning : KtFirDiagnostic<KtElement> {
         override val diagnosticClass get() = MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationWarning::class
+        val name: Name
         val valueParameter: KtSymbol
+        val baseFunctions: List<KtCallableSymbol>
     }
 
     interface TypealiasExpandsToArrayOfNothings : KtFirDiagnostic<KtElement> {

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

@@ -2233,37 +2233,49 @@ internal class CannotChangeAccessPrivilegeImpl(
 ) : KtAbstractFirDiagnostic<KtModifierListOwner>(firDiagnostic, token), KtFirDiagnostic.CannotChangeAccessPrivilege
 
 internal class MultipleDefaultsInheritedFromSupertypesImpl(
+    override val name: Name,
     override val valueParameter: KtSymbol,
+    override val baseFunctions: List<KtCallableSymbol>,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.MultipleDefaultsInheritedFromSupertypes
 
 internal class MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideImpl(
+    override val name: Name,
     override val valueParameter: KtSymbol,
+    override val baseFunctions: List<KtCallableSymbol>,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverride
 
 internal class MultipleDefaultsInheritedFromSupertypesDeprecationErrorImpl(
+    override val name: Name,
     override val valueParameter: KtSymbol,
+    override val baseFunctions: List<KtCallableSymbol>,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.MultipleDefaultsInheritedFromSupertypesDeprecationError
 
 internal class MultipleDefaultsInheritedFromSupertypesDeprecationWarningImpl(
+    override val name: Name,
     override val valueParameter: KtSymbol,
+    override val baseFunctions: List<KtCallableSymbol>,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.MultipleDefaultsInheritedFromSupertypesDeprecationWarning
 
 internal class MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationErrorImpl(
+    override val name: Name,
     override val valueParameter: KtSymbol,
+    override val baseFunctions: List<KtCallableSymbol>,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationError
 
 internal class MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationWarningImpl(
+    override val name: Name,
     override val valueParameter: KtSymbol,
+    override val baseFunctions: List<KtCallableSymbol>,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KtFirDiagnostic.MultipleDefaultsInheritedFromSupertypesWhenNoExplicitOverrideDeprecationWarning

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

@@ -890,22 +890,30 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         }
 
         val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES by error<KtElement>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT) {
+            parameter<Name>("name")
             parameter<FirValueParameterSymbol>("valueParameter")
+            parameter<List<FirCallableSymbol<*>>>("baseFunctions")
         }
         val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE by error<KtElement>(PositioningStrategy.DECLARATION_NAME) {
+            parameter<Name>("name")
             parameter<FirValueParameterSymbol>("valueParameter")
+            parameter<List<FirCallableSymbol<*>>>("baseFunctions")
         }
         val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION by deprecationError<KtElement>(
             LanguageFeature.ProhibitAllMultipleDefaultsInheritedFromSupertypes,
             PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT
         ) {
+            parameter<Name>("name")
             parameter<FirValueParameterSymbol>("valueParameter")
+            parameter<List<FirCallableSymbol<*>>>("baseFunctions")
         }
         val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION by deprecationError<KtElement>(
             LanguageFeature.ProhibitAllMultipleDefaultsInheritedFromSupertypes,
             PositioningStrategy.DECLARATION_NAME
         ) {
+            parameter<Name>("name")
             parameter<FirValueParameterSymbol>("valueParameter")
+            parameter<List<FirCallableSymbol<*>>>("baseFunctions")
         }
 
         val TYPEALIAS_EXPANDS_TO_ARRAY_OF_NOTHINGS by error<KtElement> {

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

@@ -493,10 +493,10 @@ object FirErrors {
     val DATA_CLASS_OVERRIDE_DEFAULT_VALUES by error2<KtElement, FirCallableSymbol<*>, FirClassSymbol<*>>(SourceElementPositioningStrategies.DATA_MODIFIER)
     val CANNOT_WEAKEN_ACCESS_PRIVILEGE by error3<KtModifierListOwner, Visibility, FirCallableSymbol<*>, Name>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
     val CANNOT_CHANGE_ACCESS_PRIVILEGE by error3<KtModifierListOwner, Visibility, FirCallableSymbol<*>, Name>(SourceElementPositioningStrategies.VISIBILITY_MODIFIER)
-    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES by error1<KtElement, FirValueParameterSymbol>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
+    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES by error3<KtElement, Name, FirValueParameterSymbol, List<FirCallableSymbol<*>>>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
-    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE by error1<KtElement, FirValueParameterSymbol>(SourceElementPositioningStrategies.DECLARATION_NAME)
+    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE by error3<KtElement, Name, FirValueParameterSymbol, List<FirCallableSymbol<*>>>(SourceElementPositioningStrategies.DECLARATION_NAME)
-    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION by deprecationError1<KtElement, FirValueParameterSymbol>(ProhibitAllMultipleDefaultsInheritedFromSupertypes, SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
+    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION by deprecationError3<KtElement, Name, FirValueParameterSymbol, List<FirCallableSymbol<*>>>(ProhibitAllMultipleDefaultsInheritedFromSupertypes, SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
-    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION by deprecationError1<KtElement, FirValueParameterSymbol>(ProhibitAllMultipleDefaultsInheritedFromSupertypes, SourceElementPositioningStrategies.DECLARATION_NAME)
+    val MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION by deprecationError3<KtElement, Name, FirValueParameterSymbol, List<FirCallableSymbol<*>>>(ProhibitAllMultipleDefaultsInheritedFromSupertypes, SourceElementPositioningStrategies.DECLARATION_NAME)
     val TYPEALIAS_EXPANDS_TO_ARRAY_OF_NOTHINGS by error1<KtElement, ConeKotlinType>()
     val OVERRIDING_FINAL_MEMBER by error2<KtNamedDeclaration, FirCallableSymbol<*>, Name>(SourceElementPositioningStrategies.OVERRIDE_MODIFIER)
     val RETURN_TYPE_MISMATCH_ON_INHERITANCE by error2<KtClassOrObject, FirCallableSymbol<*>, FirCallableSymbol<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)

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

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.fir.isSubstitutionOverride
 import org.jetbrains.kotlin.fir.scopes.processAllFunctions
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirValueParameterSymbol
+import org.jetbrains.kotlin.name.Name
 
 object FirMultipleDefaultsInheritedFromSupertypesChecker : FirRegularClassChecker() {
     override fun check(declaration: FirRegularClass, context: CheckerContext, reporter: DiagnosticReporter) {
@@ -48,9 +49,9 @@ object FirMultipleDefaultsInheritedFromSupertypesChecker : FirRegularClassChecke
         val overriddenFunctionsK1WouldConsider = overriddenFunctions.filter { it.containingClassLookupTag() in immediateSupertypes }
 
         for ((index, parameter) in function.valueParameterSymbols.withIndex()) {
-            val basesWithDefaultValues = overriddenFunctions.count { it.valueParameterSymbols[index].hasDefaultValue }
+            val basesWithDefaultValues = overriddenFunctions.filter { it.valueParameterSymbols[index].hasDefaultValue }
 
-            if (basesWithDefaultValues <= 1) {
+            if (basesWithDefaultValues.size <= 1) {
                 continue
             }
 
@@ -58,11 +59,15 @@ object FirMultipleDefaultsInheritedFromSupertypesChecker : FirRegularClassChecke
 
             when {
                 !isExplicitOverride -> {
-                    reportDiagnosticForImplicitOverride(k1WouldMiss, declaration.source, parameter, context, reporter)
+                    reportDiagnosticForImplicitOverride(
+                        k1WouldMiss, declaration.source, function.name, parameter, basesWithDefaultValues, context, reporter
+                    )
                     // Avoid duplicates
                     break
                 }
-                else -> reportDiagnosticForExplicitOverride(k1WouldMiss, parameter, context, reporter)
+                else -> reportDiagnosticForExplicitOverride(
+                    k1WouldMiss, function.name, parameter, basesWithDefaultValues, context, reporter
+                )
             }
         }
     }
@@ -70,33 +75,37 @@ object FirMultipleDefaultsInheritedFromSupertypesChecker : FirRegularClassChecke
     private fun reportDiagnosticForImplicitOverride(
         k1WouldMiss: Boolean,
         source: KtSourceElement?,
+        name: Name,
         parameter: FirValueParameterSymbol,
+        basesWithDefaultValues: List<FirNamedFunctionSymbol>,
         context: CheckerContext,
         reporter: DiagnosticReporter,
     ): Unit = when {
         k1WouldMiss -> reporter.reportOn(
             source, FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION,
-            parameter, context,
+            name, parameter, basesWithDefaultValues, context,
         )
         else -> reporter.reportOn(
             source, FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE,
-            parameter, context,
+            name, parameter, basesWithDefaultValues, context,
         )
     }
 
     private fun reportDiagnosticForExplicitOverride(
         k1WouldMiss: Boolean,
+        name: Name,
         parameter: FirValueParameterSymbol,
+        basesWithDefaultValues: List<FirNamedFunctionSymbol>,
         context: CheckerContext,
         reporter: DiagnosticReporter,
     ): Unit = when {
         k1WouldMiss -> reporter.reportOn(
             parameter.source, FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION,
-            parameter, context,
+            name, parameter, basesWithDefaultValues, context,
         )
         else -> reporter.reportOn(
             parameter.source, FirErrors.MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES,
-            parameter, context,
+            name, parameter, basesWithDefaultValues, context,
         )
     }
 }

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

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.diagnostics.WhenMissingCase
 import org.jetbrains.kotlin.diagnostics.rendering.ContextIndependentParameterRenderer
 import org.jetbrains.kotlin.diagnostics.rendering.Renderer
 import org.jetbrains.kotlin.fir.FirModuleData
+import org.jetbrains.kotlin.fir.containingClassLookupTag
 import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.calleeReference
@@ -66,6 +67,13 @@ object FirDiagnosticRenderers {
         }
     }
 
+    val CALLABLES_FQ_NAMES = object : ContextIndependentParameterRenderer<Collection<FirCallableSymbol<*>>> {
+        override fun render(obj: Collection<FirCallableSymbol<*>>) = "\n" + obj.joinToString("\n") { symbol ->
+            val origin = symbol.containingClassLookupTag()?.classId?.asFqNameString()
+            INDENTATION_UNIT + SYMBOL.render(symbol) + origin?.let { ", defined in $it" }.orEmpty()
+        } + "\n"
+    }
+
     val RENDER_COLLECTION_OF_TYPES = Renderer { types: Collection<ConeKotlinType> ->
         types.joinToString(separator = ", ") { type ->
             RENDER_TYPE.render(type)

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

@@ -16,12 +16,14 @@ import org.jetbrains.kotlin.diagnostics.KtDiagnosticRenderers.TO_STRING
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticRenderers.VISIBILITY
 import org.jetbrains.kotlin.diagnostics.rendering.BaseDiagnosticRendererFactory
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.CLASS_KIND
+import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.NAME
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.RENDER_POSITION_VARIANCE
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.STRING
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.commaSeparated
 import org.jetbrains.kotlin.diagnostics.rendering.LanguageFeatureMessageRenderer
 import org.jetbrains.kotlin.diagnostics.rendering.Renderer
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.AMBIGUOUS_CALLS
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.CALLABLES_FQ_NAMES
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.CALLEE_NAME
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.DECLARATION_NAME
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.FOR_OPTIONAL_OPERATOR
@@ -1513,28 +1515,37 @@ object FirErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
             FQ_NAMES_IN_TYPES
         )
 
-        val multipleDefaultsMessage = "More than one overridden function declares a default value for ''{0}''."
+        val multipleDefaultsMessage = "More than one function overridden by ''{0}'' declares a default value for ''{1}'': {2}"
-        val multipleDefaultsNotAllowed = " As the compiler can not make sure these values agree, this is not allowed."
+        val multipleDefaultsNotAllowed = "As the compiler can not make sure these values agree, this is not allowed."
         map.put(
             MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES,
             multipleDefaultsMessage + multipleDefaultsNotAllowed,
-            SYMBOL
+            NAME,
+            SYMBOL,
+            CALLABLES_FQ_NAMES,
         )
         map.put(
             MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE,
             multipleDefaultsMessage + multipleDefaultsNotAllowed,
-            SYMBOL
+            NAME,
+            SYMBOL,
+            CALLABLES_FQ_NAMES,
         )
-        val multipleDefaultsDiscouraged = " As the compiler can not make sure these values agree, this will be prohibited in the Future."
+        val multipleDefaultsDiscouraged = "As the compiler can not make sure these values agree, this will be prohibited in the future." +
+                " See: https://youtrack.jetbrains.com/issue/KT-36188"
         map.put(
             MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_DEPRECATION,
             multipleDefaultsMessage + multipleDefaultsDiscouraged,
-            SYMBOL
+            NAME,
+            SYMBOL,
+            CALLABLES_FQ_NAMES,
         )
         map.put(
             MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE_DEPRECATION,
             multipleDefaultsMessage + multipleDefaultsDiscouraged,
-            SYMBOL
+            NAME,
+            SYMBOL,
+            CALLABLES_FQ_NAMES,
         )
 
         map.put(TYPEALIAS_EXPANDS_TO_ARRAY_OF_NOTHINGS, "Type alias expanded to malformed type ''{0}''", RENDER_TYPE)

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

@@ -126,4 +126,4 @@ private fun StringBuilder.renderIncompatibleClassScopes(
     })
 }
 
-private const val INDENTATION_UNIT = "    "
+internal const val INDENTATION_UNIT = "    "

compiler/testData/diagnostics/tests/annotations/rendering/multipleInheritedDefaults.fir.kt

@@ -17,10 +17,10 @@ interface B {
     fun foo(@An a: @An Int = @An 2)
 }
 
-<!MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE("@An() a: @R|An|()  Int = ...")!>class AB1<!> : A, B
+<!MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES_WHEN_NO_EXPLICIT_OVERRIDE("foo; @An() a: @R|An|()  Int = ...;     @An() fun foo(@An() a: @R|An|()  Int = ...): Unit, defined in A    @An() fun foo(@An() a: @R|An|()  Int = ...): Unit, defined in B")!>class AB1<!> : A, B
 
 @An
 class AB2 : A, B {
     @An
-    override fun foo(<!MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES("@An() a: @R|An|()  Int")!>@An a: @An Int<!>) {}
+    override fun foo(<!MULTIPLE_DEFAULTS_INHERITED_FROM_SUPERTYPES("foo; @An() a: @R|An|()  Int;     @An() fun foo(@An() a: @R|An|()  Int = ...): Unit, defined in A    @An() fun foo(@An() a: @R|An|()  Int = ...): Unit, defined in B")!>@An a: @An Int<!>) {}
 }