FIR: introduce MANY_*_MEMBER_NOT_IMPLEMENTED diagnostic

compiler/fir/analysis-tests/testData/resolve/incorrectSuperCall.kt

@@ -11,7 +11,7 @@ open class B {
     open fun baz() {}
 }
 
-class C : A, B() {
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class C<!> : A, B() {
     override fun foo() {
         super.foo()
 

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

@@ -16,11 +16,21 @@ import org.jetbrains.kotlin.fir.analysis.checkers.getContainingClass
 import org.jetbrains.kotlin.fir.analysis.checkers.modality
 import org.jetbrains.kotlin.fir.analysis.checkers.unsubstitutedScope
 import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
-import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ABSTRACT_MEMBER_NOT_IMPLEMENTED
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MANY_IMPL_MEMBER_NOT_IMPLEMENTED
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.containingClass
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.languageVersionSettings
+import org.jetbrains.kotlin.fir.resolve.toSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirIntersectionCallableSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirIntersectionOverrideFunctionSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirIntersectionOverridePropertySymbol
 import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.fir.types.isNullableAny
 import org.jetbrains.kotlin.util.OperatorNameConventions
@@ -40,6 +50,7 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
         val classScope = declaration.unsubstitutedScope(context)
 
         val notImplementedSymbols = mutableListOf<FirCallableSymbol<*>>()
+        val notImplementedIntersectionSymbols = mutableListOf<FirCallableSymbol<*>>()
         val invisibleSymbols = mutableListOf<FirCallableSymbol<*>>()
         val classPackage = declaration.symbol.classId.packageFqName
 
@@ -64,6 +75,15 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
         for (name in classScope.getCallableNames()) {
             classScope.processFunctionsByName(name) { namedFunctionSymbol ->
                 val simpleFunction = namedFunctionSymbol.fir
+                if (namedFunctionSymbol is FirIntersectionOverrideFunctionSymbol) {
+                    if (namedFunctionSymbol.intersections.count {
+                            (it.fir as FirCallableMemberDeclaration).modality != Modality.ABSTRACT
+                        } > 1 && simpleFunction.getContainingClass(context) === declaration
+                    ) {
+                        notImplementedIntersectionSymbols += namedFunctionSymbol
+                        return@processFunctionsByName
+                    }
+                }
                 if (!simpleFunction.shouldBeImplemented()) return@processFunctionsByName
                 if (declaration is FirRegularClass && declaration.isData && simpleFunction.matchesDataClassSyntheticMemberSignatures) {
                     return@processFunctionsByName
@@ -79,6 +99,15 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
             }
             classScope.processPropertiesByName(name) { propertySymbol ->
                 val property = propertySymbol.fir as? FirProperty ?: return@processPropertiesByName
+                if (propertySymbol is FirIntersectionOverridePropertySymbol) {
+                    if (propertySymbol.intersections.count {
+                            (it.fir as FirCallableMemberDeclaration).modality != Modality.ABSTRACT
+                        } > 1 && property.getContainingClass(context) === declaration
+                    ) {
+                        notImplementedIntersectionSymbols += propertySymbol
+                        return@processPropertiesByName
+                    }
+                }
                 if (!property.shouldBeImplemented()) return@processPropertiesByName
 
                 if (property.isInvisible()) {
@@ -92,17 +121,30 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
         if (notImplementedSymbols.isNotEmpty()) {
             val notImplemented = notImplementedSymbols.first().fir
             if (notImplemented.isFromInterfaceOrEnum(context)) {
-                reporter.reportOn(source, FirErrors.ABSTRACT_MEMBER_NOT_IMPLEMENTED, declaration, notImplemented, context)
+                reporter.reportOn(source, ABSTRACT_MEMBER_NOT_IMPLEMENTED, declaration, notImplemented, context)
             } else {
-                reporter.reportOn(source, FirErrors.ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED, declaration, notImplemented, context)
+                reporter.reportOn(source, ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED, declaration, notImplemented, context)
             }
         }
         if (invisibleSymbols.isNotEmpty()) {
             val invisible = invisibleSymbols.first().fir
             if (context.session.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitInvisibleAbstractMethodsInSuperclasses)) {
-                reporter.reportOn(source, FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER, declaration, invisible, context)
+                reporter.reportOn(source, INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER, declaration, invisible, context)
             } else {
-                reporter.reportOn(source, FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING, declaration, invisible, context)
+                reporter.reportOn(source, INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING, declaration, invisible, context)
+            }
+        }
+        if (notImplementedIntersectionSymbols.isNotEmpty()) {
+            val notImplementedIntersectionSymbol = notImplementedIntersectionSymbols.first()
+            val notImplementedIntersection = notImplementedIntersectionSymbol.fir
+            val intersections = (notImplementedIntersectionSymbol as FirIntersectionCallableSymbol).intersections
+            if (intersections.any {
+                    (it.containingClass()?.toSymbol(context.session)?.fir as? FirRegularClass)?.classKind == ClassKind.CLASS
+                }
+            ) {
+                reporter.reportOn(source, MANY_IMPL_MEMBER_NOT_IMPLEMENTED, declaration, notImplementedIntersection, context)
+            } else {
+                reporter.reportOn(source, MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED, declaration, notImplementedIntersection, context)
             }
         }
     }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/FirFunctionSymbol.kt

@@ -25,10 +25,14 @@ open class FirNamedFunctionSymbol(
     callableId: CallableId,
 ) : FirFunctionSymbol<FirSimpleFunction>(callableId)
 
+interface FirIntersectionCallableSymbol {
+    val intersections: Collection<FirCallableSymbol<*>>
+}
+
 class FirIntersectionOverrideFunctionSymbol(
     callableId: CallableId,
-    val intersections: Collection<FirCallableSymbol<*>>
+    override val intersections: Collection<FirCallableSymbol<*>>
-) : FirNamedFunctionSymbol(callableId)
+) : FirNamedFunctionSymbol(callableId), FirIntersectionCallableSymbol
 
 class FirConstructorSymbol(
     callableId: CallableId

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/FirVariableSymbol.kt

@@ -29,8 +29,8 @@ open class FirPropertySymbol(
 
 class FirIntersectionOverridePropertySymbol(
     callableId: CallableId,
-    val intersections: Collection<FirCallableSymbol<*>>
+    override val intersections: Collection<FirCallableSymbol<*>>
-) : FirPropertySymbol(callableId)
+) : FirPropertySymbol(callableId), FirIntersectionCallableSymbol
 
 class FirBackingFieldSymbol(callableId: CallableId) : FirVariableSymbol<FirProperty>(callableId)
 

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

@@ -44,5 +44,5 @@ interface GI : G {
     override fun a(@An arg: @An Int) {}
 }
 
-class AG1(val a: A, val g: G) : A by a, G by g
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class AG1<!>(val a: A, val g: G) : A by a, G by g
-class AG2() : AI, GI
+<!MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED!>class AG2<!>() : AI, GI

compiler/testData/diagnostics/tests/delegation/Delegation_ClashingFunctions.fir.kt

@@ -10,9 +10,9 @@ interface Three {
     public fun foo(): String
 }
 
-class Test123(val v1: One, val v2: Two, val v3: Three) : One by v1, Two by v2, Three by v3 { }
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class Test123<!>(val v1: One, val v2: Two, val v3: Three) : One by v1, Two by v2, Three by v3 { }
-class Test132(val v1: One, val v2: Two, val v3: Three) : One by v1, Three by v3, Two by v2 { }
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class Test132<!>(val v1: One, val v2: Two, val v3: Three) : One by v1, Three by v3, Two by v2 { }
-class Test312(val v1: One, val v2: Two, val v3: Three) : Three by v3, One by v1, Two by v2 { }
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class Test312<!>(val v1: One, val v2: Two, val v3: Three) : Three by v3, One by v1, Two by v2 { }
-class Test321(val v1: One, val v2: Two, val v3: Three) : Three by v3, Two by v2, One by v1 { }
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class Test321<!>(val v1: One, val v2: Two, val v3: Three) : Three by v3, Two by v2, One by v1 { }
-class Test231(val v1: One, val v2: Two, val v3: Three) : Two by v2, Three by v3, One by v1 { }
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class Test231<!>(val v1: One, val v2: Two, val v3: Three) : Two by v2, Three by v3, One by v1 { }
-class Test213(val v1: One, val v2: Two, val v3: Three) : Two by v2, One by v1, Three by v3 { }
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class Test213<!>(val v1: One, val v2: Two, val v3: Three) : Two by v2, One by v1, Three by v3 { }

compiler/testData/diagnostics/tests/delegation/Delegation_MultipleDelegates.fir.kt

@@ -1,19 +0,0 @@
-// !DIAGNOSTICS: -CONFLICTING_JVM_DECLARATIONS
-interface One {
-  public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int
-  private fun boo() = 10
-}
-interface Two {
-  public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int
-}
-
-interface OneImpl : One {
-  public override fun foo() = 1
-}
-interface TwoImpl : Two {
-  public override fun foo() = 2
-}
-
-class Test1() : TwoImpl, OneImpl {}
-class Test2(a : One) : One by a, Two {}
-class Test3(a : One, b : Two) : Two by b, One by a {}

compiler/testData/diagnostics/tests/delegation/Delegation_MultipleDelegates.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -CONFLICTING_JVM_DECLARATIONS
 interface One {
   public <!REDUNDANT_OPEN_IN_INTERFACE!>open<!> fun foo() : Int

compiler/testData/diagnostics/tests/delegation/memberHidesSupertypeOverride/sameDelegationInHierarchy.fir.kt

@@ -9,7 +9,7 @@ class Delegate : Base {
 public open class MyClass : Base by Delegate()
 
 fun box(): String {
-    object : MyClass(), Base by Delegate() {
+    <!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>object<!> : MyClass(), Base by Delegate() {
     }
     return "OK"
 }

compiler/testData/diagnostics/tests/deprecated/deprecatedInheritance.fir.kt

@@ -77,7 +77,7 @@ open class NWEH: NotDeprecated, WarningDeprecated, ErrorDeprecated, HiddenDeprec
 
 class WE2: WE()
 
-class NWE2: WE(), NotDeprecated
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class NWE2<!>: WE(), NotDeprecated
 
 class NWE3: WE(), NotDeprecated {
     override fun f() {

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

@@ -1,11 +0,0 @@
-interface A {
-    fun f(): String = "string"
-}
-
-open class B {
-    open fun f(): CharSequence = "charSequence"
-}
-
-class C : B(), A
-
-val obj: A = object : B(), A {}

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

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface A {
     fun f(): String = "string"
 }

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

@@ -10,4 +10,4 @@ object Impl : D, E {
     override fun foo() {}
 }
 
-val obj: D = object : D by Impl, E by Impl {}
+val obj: D = <!MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED!>object<!> : D by Impl, E by Impl {}

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

@@ -1,17 +0,0 @@
-package d
-
-interface A {
-    fun foo() = 1
-}
-
-interface B {
-    fun foo() = 2
-}
-
-open class C : A, B {}
-
-interface E {
-    fun foo(): Int
-}
-
-class D : C() {}

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

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 package d
 
 interface A {

compiler/testData/diagnostics/tests/regressions/kt302.fir.kt

@@ -1,13 +0,0 @@
-// KT-302 Report an error when inheriting many implementations of the same member
-
-package kt302
-
-interface A {
-    open fun foo() {}
-}
-
-interface B {
-    open fun foo() {}
-}
-
-class C : A, B {} //should be error here

compiler/testData/diagnostics/tests/regressions/kt302.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // KT-302 Report an error when inheriting many implementations of the same member
 
 package kt302

compiler/testData/diagnostics/testsWithStdLib/annotations/jvmDefault/superCall.fir.kt

@@ -53,7 +53,7 @@ class ManySupers2: Foo2(), C {
     }
 }
 
-class ManySupers3: Bar2(), C {
+<!MANY_IMPL_MEMBER_NOT_IMPLEMENTED!>class ManySupers3<!>: Bar2(), C {
     fun foo() {
         super<Bar2>.test()
         super<C>.test()

compiler/testData/diagnostics/testsWithStdLib/coroutines/mixingSuspendability.fir.kt

@@ -1,6 +1,6 @@
 interface AsyncVal { suspend fun getVal(): Int = 1}
 interface SyncVal { fun getVal(): Int = 1 }
 
-class MixSuspend : AsyncVal, SyncVal {
+<!MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED!>class MixSuspend<!> : AsyncVal, SyncVal {
 
 }