Forbid numbered KSuspendFunction interfaces usage as supertypes

#KT-24853 Fixed

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -291,6 +291,7 @@ public interface Errors {
     DiagnosticFactory0<KtTypeReference> SUPERTYPE_NOT_A_CLASS_OR_INTERFACE = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> SUPERTYPE_IS_EXTENSION_FUNCTION_TYPE = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> SUPERTYPE_IS_SUSPEND_FUNCTION_TYPE = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<KtTypeReference> SUPERTYPE_IS_KSUSPEND_FUNCTION_TYPE = DiagnosticFactory0.create(ERROR);
 
     DiagnosticFactory0<KtTypeReference> MANY_CLASSES_IN_SUPERTYPE_LIST = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> SUPERTYPE_APPEARS_TWICE = DiagnosticFactory0.create(ERROR);

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -573,6 +573,7 @@ public class DefaultErrorMessages {
         MAP.put(SUPERTYPE_IS_EXTENSION_FUNCTION_TYPE, "Extension function type is not allowed as supertypes");
         MAP.put(SUPERTYPE_INITIALIZED_IN_INTERFACE, "Interfaces cannot initialize supertypes");
         MAP.put(SUPERTYPE_IS_SUSPEND_FUNCTION_TYPE, "Suspend function type is not allowed as supertypes");
+        MAP.put(SUPERTYPE_IS_KSUSPEND_FUNCTION_TYPE, "KSuspendFunctionN interfaces are not allowed as supertypes");
         MAP.put(CLASS_IN_SUPERTYPE_FOR_ENUM, "Enum class cannot inherit from classes");
         MAP.put(CONSTRUCTOR_IN_INTERFACE, "An interface may not have a constructor");
         MAP.put(METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE, "An interface may not implement a method of 'Any'");

compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java

@@ -559,6 +559,9 @@ public class BodyResolver {
                 else if (FunctionTypesKt.isSuspendFunctionType(supertype)) {
                     trace.report(SUPERTYPE_IS_SUSPEND_FUNCTION_TYPE.on(typeReference));
                 }
+                else if (FunctionTypesKt.isKSuspendFunctionType(supertype)) {
+                    trace.report(SUPERTYPE_IS_KSUSPEND_FUNCTION_TYPE.on(typeReference));
+                }
 
                 if (classDescriptor.getKind() != ClassKind.INTERFACE) {
                     if (supertypeOwner.getKind() == ClassKind.ENUM_CLASS) {

compiler/testData/diagnostics/testsWithStdLib/coroutines/kSuspendFunctionAsSupertype.kt

@@ -0,0 +1,5 @@
+// SKIP_TXT
+
+import kotlin.reflect.*
+
+<!ABSTRACT_MEMBER_NOT_IMPLEMENTED!>class A<!>: <!SUPERTYPE_IS_KSUSPEND_FUNCTION_TYPE!>KSuspendFunction0<Unit><!> {}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java

@@ -1468,6 +1468,11 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/irrelevantSuspendDeclarations.kt");
         }
 
+        @TestMetadata("kSuspendFunctionAsSupertype.kt")
+        public void testKSuspendFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kSuspendFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt18292.kt")
         public void testKt18292_1_2() throws Exception {
             runTestWithPackageReplacement("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt18292.kt", "kotlin.coroutines.experimental");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java

@@ -1468,6 +1468,11 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
             runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/irrelevantSuspendDeclarations.kt");
         }
 
+        @TestMetadata("kSuspendFunctionAsSupertype.kt")
+        public void testKSuspendFunctionAsSupertype() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/coroutines/kSuspendFunctionAsSupertype.kt");
+        }
+
         @TestMetadata("kt18292.kt")
         public void testKt18292_1_2() throws Exception {
             runTestWithPackageReplacement("compiler/testData/diagnostics/testsWithStdLib/coroutines/kt18292.kt", "kotlin.coroutines.experimental");

core/descriptors/src/org/jetbrains/kotlin/builtins/functionTypes.kt

@@ -58,6 +58,9 @@ val KotlinType.isFunctionType: Boolean
 val KotlinType.isSuspendFunctionType: Boolean
     get() = constructor.declarationDescriptor?.getFunctionalClassKind() == FunctionClassDescriptor.Kind.SuspendFunction
 
+val KotlinType.isKSuspendFunctionType: Boolean
+    get() = constructor.declarationDescriptor?.getFunctionalClassKind() == FunctionClassDescriptor.Kind.KSuspendFunction
+
 val KotlinType.isFunctionOrSuspendFunctionType: Boolean
     get() = isFunctionType || isSuspendFunctionType