[FIR JS] Support WRONG_MULTIPLE_INHERITANCE

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

@@ -598,6 +598,13 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirJsErrors.WRONG_MULTIPLE_INHERITANCE) { firDiagnostic ->
+        WrongMultipleInheritanceImpl(
+            firSymbolBuilder.callableBuilder.buildCallableSymbol(firDiagnostic.a),
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.CONSTRUCTOR_IN_OBJECT) { firDiagnostic ->
         ConstructorInObjectImpl(
             firDiagnostic as KtPsiDiagnostic,

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

@@ -447,6 +447,11 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val candidates: List<KtType>
     }
 
+    abstract class WrongMultipleInheritance : KtFirDiagnostic<KtElement>() {
+        override val diagnosticClass get() = WrongMultipleInheritance::class
+        abstract val symbol: KtCallableSymbol
+    }
+
     abstract class ConstructorInObject : KtFirDiagnostic<KtDeclaration>() {
         override val diagnosticClass get() = ConstructorInObject::class
     }

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

@@ -527,6 +527,12 @@ internal class AmbiguousSuperImpl(
     override val token: KtLifetimeToken,
 ) : KtFirDiagnostic.AmbiguousSuper(), KtAbstractFirDiagnostic<KtSuperExpression>
 
+internal class WrongMultipleInheritanceImpl(
+    override val symbol: KtCallableSymbol,
+    override val firDiagnostic: KtPsiDiagnostic,
+    override val token: KtLifetimeToken,
+) : KtFirDiagnostic.WrongMultipleInheritance(), KtAbstractFirDiagnostic<KtElement>
+
 internal class ConstructorInObjectImpl(
     override val firDiagnostic: KtPsiDiagnostic,
     override val token: KtLifetimeToken,

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

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.fir.checkers.generator.diagnostics
 import org.jetbrains.kotlin.fir.PrivateForInline
 import org.jetbrains.kotlin.fir.checkers.generator.diagnostics.model.DiagnosticList
 import org.jetbrains.kotlin.fir.checkers.generator.diagnostics.model.PositioningStrategy
+import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.psi.KtElement
 
 @Suppress("UNUSED_VARIABLE", "LocalVariableName", "ClassName", "unused")
@@ -19,4 +20,10 @@ object JS_DIAGNOSTICS_LIST : DiagnosticList("FirJsErrors") {
         val JS_MODULE_PROHIBITED_ON_NON_NATIVE by error<KtElement>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT)
         val NESTED_JS_MODULE_PROHIBITED by error<KtElement>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT)
     }
+
+    val SUPERTYPES by object : DiagnosticGroup("Supertypes") {
+        val WRONG_MULTIPLE_INHERITANCE by error<KtElement>(PositioningStrategy.DECLARATION_SIGNATURE_OR_DEFAULT) {
+            parameter<FirCallableSymbol<*>>("symbol")
+        }
+    }
 }

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

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.diagnostics.*
 import org.jetbrains.kotlin.diagnostics.SourceElementPositioningStrategies
 import org.jetbrains.kotlin.diagnostics.rendering.RootDiagnosticRendererFactory
 import org.jetbrains.kotlin.fir.analysis.diagnostics.*
+import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.psi.KtElement
 
 /*
@@ -23,6 +24,9 @@ object FirJsErrors {
     val JS_MODULE_PROHIBITED_ON_NON_NATIVE by error0<KtElement>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
     val NESTED_JS_MODULE_PROHIBITED by error0<KtElement>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
 
+    // Supertypes
+    val WRONG_MULTIPLE_INHERITANCE by error1<KtElement, FirCallableSymbol<*>>(SourceElementPositioningStrategies.DECLARATION_SIGNATURE_OR_DEFAULT)
+
     init {
         RootDiagnosticRendererFactory.registerFactory(FirJsErrorsDefaultMessages)
     }

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

@@ -7,11 +7,13 @@ package org.jetbrains.kotlin.fir.analysis.diagnostics.js
 
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactoryToRendererMap
 import org.jetbrains.kotlin.diagnostics.rendering.BaseDiagnosticRendererFactory
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers
 import org.jetbrains.kotlin.fir.analysis.diagnostics.checkMissingMessages
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.JS_MODULE_PROHIBITED_ON_NON_NATIVE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.JS_MODULE_PROHIBITED_ON_VAR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.NESTED_JS_MODULE_PROHIBITED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.WRONG_JS_QUALIFIER
+import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors.WRONG_MULTIPLE_INHERITANCE
 
 @Suppress("unused")
 object FirJsErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
@@ -23,6 +25,11 @@ object FirJsErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
             NESTED_JS_MODULE_PROHIBITED,
             "@JsModule and @JsNonModule can't appear on here since the file is already marked by either @JsModule or @JsNonModule"
         )
+        map.put(
+            WRONG_MULTIPLE_INHERITANCE,
+            "Can''t apply multiple inheritance here, since it''s impossible to generate bridge for system function {0}",
+            FirDiagnosticRenderers.SYMBOL
+        )
 
         map.checkMissingMessages(FirJsErrors)
     }

compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/JsDeclarationCheckers.kt

@@ -5,13 +5,8 @@
 
 package org.jetbrains.kotlin.fir.analysis.js.checkers
 
-import org.jetbrains.kotlin.fir.analysis.checkers.declaration.DeclarationCheckers
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.*
-import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirBasicDeclarationChecker
+import org.jetbrains.kotlin.fir.analysis.js.checkers.declaration.*
-import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirFunctionChecker
-import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirPropertyChecker
-import org.jetbrains.kotlin.fir.analysis.js.checkers.declaration.FirJsInlineDeclarationChecker
-import org.jetbrains.kotlin.fir.analysis.js.checkers.declaration.FirJsInlinePropertyChecker
-import org.jetbrains.kotlin.fir.analysis.js.checkers.declaration.FirJsModuleChecker
 
 object JsDeclarationCheckers : DeclarationCheckers() {
     override val functionCheckers: Set<FirFunctionChecker>
@@ -28,4 +23,9 @@ object JsDeclarationCheckers : DeclarationCheckers() {
         get() = setOf(
             FirJsModuleChecker,
         )
+
+    override val classCheckers: Set<FirClassChecker>
+        get() = setOf(
+            FirJsMultipleInheritanceChecker,
+        )
 }

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

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2010-2023 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.fir.analysis.js.checkers.declaration
+
+import org.jetbrains.kotlin.builtins.StandardNames
+import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirClassChecker
+import org.jetbrains.kotlin.fir.analysis.checkers.overriddenFunctions
+import org.jetbrains.kotlin.fir.analysis.checkers.unsubstitutedScope
+import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors
+import org.jetbrains.kotlin.fir.declarations.FirClass
+import org.jetbrains.kotlin.fir.resolve.defaultType
+import org.jetbrains.kotlin.fir.scopes.getFunctions
+import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.classId
+import org.jetbrains.kotlin.fir.types.isSubtypeOf
+import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.util.OperatorNameConventions
+
+object FirJsMultipleInheritanceChecker : FirClassChecker() {
+    override fun check(declaration: FirClass, context: CheckerContext, reporter: DiagnosticReporter) {
+        declaration.checkFunctionIfSubtypeOf(
+            functionToCheck = OperatorNameConventions.GET,
+            supertype = context.session.builtinTypes.charSequenceType.type,
+            context, reporter,
+        )
+
+        declaration.checkFunctionIfSubtypeOf(
+            functionToCheck = StandardNames.NEXT_CHAR,
+            supertype = context.session.builtinTypes.charIteratorType.type,
+            context, reporter,
+        )
+    }
+
+    private fun FirClass.checkFunctionIfSubtypeOf(
+        functionToCheck: Name,
+        supertype: ConeKotlinType,
+        context: CheckerContext,
+        reporter: DiagnosticReporter,
+    ) {
+        if (!defaultType().isSubtypeOf(supertype, context.session)) {
+            return
+        }
+
+        val scope = unsubstitutedScope(context)
+        val overridesWithSameName = scope.getFunctions(functionToCheck)
+
+        for (function in overridesWithSameName) {
+            val overridden = function.overriddenFunctions(symbol, context)
+
+            if (
+                overridden.size > 1 &&
+                overridden.any { it.callableId.classId == supertype.classId }
+            ) {
+                reporter.reportOn(source, FirJsErrors.WRONG_MULTIPLE_INHERITANCE, function, context)
+            }
+        }
+    }
+}

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSession.kt

@@ -74,4 +74,7 @@ class BuiltinTypes {
     val charType: FirImplicitBuiltinTypeRef = FirImplicitCharTypeRef(null)
     val stringType: FirImplicitBuiltinTypeRef = FirImplicitStringTypeRef(null)
     val throwableType: FirImplicitThrowableTypeRef = FirImplicitThrowableTypeRef(null)
+
+    val charSequenceType: FirImplicitCharSequenceTypeRef = FirImplicitCharSequenceTypeRef(null)
+    val charIteratorType: FirImplicitCharIteratorTypeRef = FirImplicitCharIteratorTypeRef(null)
 }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/impl/FirImplicitBuiltinTypeRef.kt

@@ -128,6 +128,14 @@ class FirImplicitThrowableTypeRef(
     source: KtSourceElement?
 ) : FirImplicitBuiltinTypeRef(source, StandardClassIds.Throwable)
 
+class FirImplicitCharSequenceTypeRef(
+    source: KtSourceElement?
+) : FirImplicitBuiltinTypeRef(source, StandardClassIds.CharSequence)
+
+class FirImplicitCharIteratorTypeRef(
+    source: KtSourceElement?
+) : FirImplicitBuiltinTypeRef(source, StandardClassIds.CharIterator)
+
 class FirImplicitKPropertyTypeRef(
     source: KtSourceElement?,
     typeArgument: ConeTypeProjection
@@ -199,6 +207,8 @@ fun FirImplicitBuiltinTypeRef.withFakeSource(kind: KtFakeSourceElementKind): Fir
         is FirImplicitCharTypeRef -> FirImplicitCharTypeRef(newSource)
         is FirImplicitStringTypeRef -> FirImplicitStringTypeRef(newSource)
         is FirImplicitThrowableTypeRef -> FirImplicitThrowableTypeRef(newSource)
+        is FirImplicitCharSequenceTypeRef -> FirImplicitCharSequenceTypeRef(newSource)
+        is FirImplicitCharIteratorTypeRef -> FirImplicitCharIteratorTypeRef(newSource)
         is FirImplicitKPropertyTypeRef -> FirImplicitKPropertyTypeRef(
             newSource,
             typeArgument = type.typeArguments[0]

compiler/testData/diagnostics/testsWithJsStdLib/wrongMultipleInheritance.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 open class A {

core/compiler.common/src/org/jetbrains/kotlin/builtins/StandardNames.kt

@@ -34,6 +34,8 @@ object StandardNames {
 
     @JvmField val CHAR_CODE = Name.identifier("code")
 
+    @JvmField val NEXT_CHAR = Name.identifier("nextChar")
+
     @JvmField val CONTEXT_FUNCTION_TYPE_PARAMETER_COUNT_NAME = Name.identifier("count")
 
     @JvmField val DYNAMIC_FQ_NAME = FqName("<dynamic>")

core/compiler.common/src/org/jetbrains/kotlin/name/StandardClassIds.kt

@@ -116,6 +116,7 @@ object StandardClassIds {
     val Set = "Set".collectionsId()
     val Map = "Map".collectionsId()
     val MutableIterator = "MutableIterator".collectionsId()
+    val CharIterator = "CharIterator".collectionsId()
 
     val MutableIterable = "MutableIterable".collectionsId()
     val MutableCollection = "MutableCollection".collectionsId()