Prohibit functions (and constructors) with multiple vararg parameters.

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

@@ -420,6 +420,8 @@ public interface Errors {
 
     DiagnosticFactory0<KtParameter> USELESS_VARARG_ON_PARAMETER = DiagnosticFactory0.create(WARNING);
 
+    DiagnosticFactory0<KtParameter> MULTIPLE_VARARG_PARAMETERS = DiagnosticFactory0.create(ERROR, PARAMETER_VARARG_MODIFIER);
+
     // Named parameters
 
     DiagnosticFactory0<KtParameter> DEFAULT_VALUE_NOT_ALLOWED_IN_OVERRIDE = DiagnosticFactory0.create(ERROR, PARAMETER_DEFAULT_VALUE);

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/PositioningStrategies.kt

@@ -285,6 +285,13 @@ public object PositioningStrategies {
         }
     }
 
+    @JvmField public val PARAMETER_VARARG_MODIFIER: PositioningStrategy<KtParameter> = object : PositioningStrategy<KtParameter>() {
+        override fun mark(element: KtParameter): List<TextRange> {
+            val varargModifier = element.modifierList!!.getModifier(KtTokens.VARARG_KEYWORD)!!
+            return markNode(varargModifier.node)
+        }
+    }
+
     @JvmField public val CALL_ELEMENT: PositioningStrategy<PsiElement> = object : PositioningStrategy<PsiElement>() {
         override fun mark(element: PsiElement): List<TextRange> {
             return markElement((element as? KtCallElement)?.getCalleeExpression() ?: element)

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

@@ -234,6 +234,7 @@ public class DefaultErrorMessages {
 
         MAP.put(ANONYMOUS_FUNCTION_PARAMETER_WITH_DEFAULT_VALUE, "An anonymous function is not allowed to specify default values for its parameters");
         MAP.put(USELESS_VARARG_ON_PARAMETER, "Vararg on this parameter is useless");
+        MAP.put(MULTIPLE_VARARG_PARAMETERS, "Multiple vararg-parameters are prohibited");
 
         MAP.put(PROJECTION_ON_NON_CLASS_TYPE_ARGUMENT, "Projections are not allowed on type arguments of functions and properties");
         MAP.put(SUPERTYPE_NOT_INITIALIZED, "This type has a constructor, and thus must be initialized here");

compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt

@@ -130,6 +130,7 @@ class DeclarationsChecker(
         declaration.checkTypeReferences()
         modifiersChecker.checkModifiersForDeclaration(declaration, constructorDescriptor)
         identifierChecker.checkDeclaration(declaration, trace)
+        checkVarargParameters(trace, constructorDescriptor)
     }
 
     private fun checkModifiersAndAnnotationsInPackageDirective(file: KtFile) {
@@ -323,11 +324,13 @@ class DeclarationsChecker(
         else if (aClass is KtEnumEntry) {
             checkEnumEntry(aClass, classDescriptor)
         }
+
         for (memberDescriptor in classDescriptor.declaredCallableMembers) {
             if (memberDescriptor.kind != CallableMemberDescriptor.Kind.DECLARATION) continue
             val member = DescriptorToSourceUtils.descriptorToDeclaration(memberDescriptor) as? KtFunction
             if (member != null && memberDescriptor is FunctionDescriptor) {
                 checkFunctionExposedType(member, memberDescriptor)
+                checkVarargParameters(trace, memberDescriptor)
             }
         }
     }
@@ -650,7 +653,9 @@ class DeclarationsChecker(
                 trace.report(IMPLICIT_NOTHING_RETURN_TYPE.on(nameIdentifier ?: function))
             }
         }
+
         checkFunctionExposedType(function, functionDescriptor)
+        checkVarargParameters(trace, functionDescriptor)
     }
 
     private fun checkFunctionExposedType(function: KtFunction, functionDescriptor: FunctionDescriptor) {
@@ -740,6 +745,19 @@ class DeclarationsChecker(
     }
 
     companion object {
+        internal fun checkVarargParameters(trace: BindingTrace, callableDescriptor: CallableDescriptor) {
+            val numberOfVarargParameters = callableDescriptor.valueParameters.count { it.varargElementType != null }
+            if (numberOfVarargParameters > 1) {
+                for (parameter in callableDescriptor.valueParameters) {
+                    if (parameter.varargElementType != null) {
+                        val parameterDeclaration = DescriptorToSourceUtils.descriptorToDeclaration(parameter)
+                        if (parameterDeclaration is KtParameter) {
+                            trace.report(MULTIPLE_VARARG_PARAMETERS.on(parameterDeclaration))
+                        }
+                    }
+                }
+            }
+        }
 
         private fun removeDuplicateTypes(conflictingTypes: MutableSet<KotlinType>) {
             val iterator = conflictingTypes.iterator()

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/FunctionsTypingVisitor.kt

@@ -109,6 +109,7 @@ internal class FunctionsTypingVisitor(facade: ExpressionTypingInternals) : Expre
         if (!function.hasBody() && !function.hasModifier(KtTokens.EXTERNAL_KEYWORD)) {
             context.trace.report(NON_MEMBER_FUNCTION_NO_BODY.on(function, functionDescriptor))
         }
+        DeclarationsChecker.checkVarargParameters(context.trace, functionDescriptor)
 
         if (isStatement) {
             return createTypeInfo(components.dataFlowAnalyzer.checkStatementType(function, context), context)

compiler/testData/diagnostics/tests/annotations/invalidTypesInAnnotationConstructor.kt

@@ -33,11 +33,6 @@ annotation class Ann8(val p1: Array<String>,
                       val p3: Array<MyEnum>,
                       val p4: Array<Ann1>)
 
-annotation class Ann9(vararg val p1: String,
-                      vararg val p2: <!INVALID_TYPE_OF_ANNOTATION_MEMBER!>Class<*><!>,
-                      vararg val p3: MyEnum,
-                      vararg val p4: Ann1,
-                      vararg val p5: Int)
 
 // INCORRECT
 annotation class InAnn1(val p1: <!NULLABLE_TYPE_OF_ANNOTATION_MEMBER!>Int?<!>,
@@ -64,6 +59,11 @@ annotation class InAnn10(val p1: <!NULLABLE_TYPE_OF_ANNOTATION_MEMBER!>String?<!
 annotation class InAnn11(val p1: <!NULLABLE_TYPE_OF_ANNOTATION_MEMBER!>Ann1?<!>)
 annotation class InAnn12(val p1: <!NULLABLE_TYPE_OF_ANNOTATION_MEMBER!>MyEnum?<!>)
 
+annotation class InAnn13(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> val p1: String,
+                        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> val p2: <!INVALID_TYPE_OF_ANNOTATION_MEMBER!>Class<*><!>,
+                        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> val p3: MyEnum,
+                        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> val p4: Ann1,
+                        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> val p5: Int)
 
 enum class MyEnum {
     A

compiler/testData/diagnostics/tests/annotations/invalidTypesInAnnotationConstructor.txt

@@ -83,18 +83,6 @@ package test {
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
-    public final annotation class Ann9 : kotlin.Annotation {
-        public constructor Ann9(/*0*/ vararg p1: kotlin.String /*kotlin.Array<out kotlin.String>*/, /*1*/ vararg p2: java.lang.Class<*> /*kotlin.Array<out java.lang.Class<*>>*/, /*2*/ vararg p3: test.MyEnum /*kotlin.Array<out test.MyEnum>*/, /*3*/ vararg p4: test.Ann1 /*kotlin.Array<out test.Ann1>*/, /*4*/ vararg p5: kotlin.Int /*kotlin.IntArray*/)
-        public final val p1: kotlin.Array<out kotlin.String>
-        public final val p2: kotlin.Array<out java.lang.Class<*>>
-        public final val p3: kotlin.Array<out test.MyEnum>
-        public final val p4: kotlin.Array<out test.Ann1>
-        public final val p5: kotlin.IntArray
-        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
-    }
-
     public final annotation class InAnn1 : kotlin.Annotation {
         public constructor InAnn1(/*0*/ p1: kotlin.Int?, /*1*/ p3: kotlin.Short?, /*2*/ p4: kotlin.Long?, /*3*/ p5: kotlin.Double?, /*4*/ p6: kotlin.Float?, /*5*/ p7: kotlin.Char?, /*6*/ p8: kotlin.Boolean?)
         public final val p1: kotlin.Int?
@@ -133,6 +121,18 @@ package test {
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
 
+    public final annotation class InAnn13 : kotlin.Annotation {
+        public constructor InAnn13(/*0*/ vararg p1: kotlin.String /*kotlin.Array<out kotlin.String>*/, /*1*/ vararg p2: java.lang.Class<*> /*kotlin.Array<out java.lang.Class<*>>*/, /*2*/ vararg p3: test.MyEnum /*kotlin.Array<out test.MyEnum>*/, /*3*/ vararg p4: test.Ann1 /*kotlin.Array<out test.Ann1>*/, /*4*/ vararg p5: kotlin.Int /*kotlin.IntArray*/)
+        public final val p1: kotlin.Array<out kotlin.String>
+        public final val p2: kotlin.Array<out java.lang.Class<*>>
+        public final val p3: kotlin.Array<out test.MyEnum>
+        public final val p4: kotlin.Array<out test.Ann1>
+        public final val p5: kotlin.IntArray
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
     public final annotation class InAnn4 : kotlin.Annotation {
         public constructor InAnn4(/*0*/ p1: kotlin.Array<kotlin.Int>, /*1*/ p2: kotlin.Array<kotlin.Int>?)
         public final val p1: kotlin.Array<kotlin.Int>

compiler/testData/diagnostics/tests/declarationChecks/mulitpleVarargParameters.kt

@@ -0,0 +1,27 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER -PRIMARY_CONSTRUCTOR_DELEGATION_CALL_EXPECTED
+fun test(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {
+    fun test2(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {
+        class LocalClass(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {
+            constructor(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int, xx: Int) {}
+        }
+        fun test3(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {}
+    }
+}
+
+fun Any.test(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x3: Int) {}
+
+interface I {
+    fun test(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int)
+}
+
+abstract class C(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int, b: Boolean) {
+    fun test(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {}
+
+    abstract fun test2(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int)
+
+    class CC(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int, b: Boolean) {
+        constructor(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {}
+        fun test(<!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x1: Int, <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> x2: Int) {}
+    }
+}
+

compiler/testData/diagnostics/tests/declarationChecks/mulitpleVarargParameters.txt

@@ -0,0 +1,29 @@
+package
+
+public fun test(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/): kotlin.Unit
+public fun kotlin.Any.test(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/, /*2*/ vararg x3: kotlin.Int /*kotlin.IntArray*/): kotlin.Unit
+
+public abstract class C {
+    public constructor C(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/, /*2*/ b: kotlin.Boolean)
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public final fun test(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/): kotlin.Unit
+    public abstract fun test2(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public final class CC {
+        public constructor CC(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/)
+        public constructor CC(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/, /*2*/ b: kotlin.Boolean)
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final fun test(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/): kotlin.Unit
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+public interface I {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public abstract fun test(/*0*/ vararg x1: kotlin.Int /*kotlin.IntArray*/, /*1*/ vararg x2: kotlin.Int /*kotlin.IntArray*/): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/declarationChecks/valVarFunctionParameter.kt

@@ -2,9 +2,9 @@ fun f(
         <!VAL_OR_VAR_ON_FUN_PARAMETER!>val<!> a: Int,
         <!VAL_OR_VAR_ON_FUN_PARAMETER!>var<!> b: Int,
         c: Int,
-        vararg <!VAL_OR_VAR_ON_FUN_PARAMETER!>var<!> d: Int,
+        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> <!VAL_OR_VAR_ON_FUN_PARAMETER!>var<!> d: Int,
-        vararg <!VAL_OR_VAR_ON_FUN_PARAMETER!>val<!> e: Int,
+        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> <!VAL_OR_VAR_ON_FUN_PARAMETER!>val<!> e: Int,
-        vararg f: Int
+        <!MULTIPLE_VARARG_PARAMETERS!>vararg<!> f: Int
 ) {
     
     

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

@@ -4224,6 +4224,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("mulitpleVarargParameters.kt")
+            public void testMulitpleVarargParameters() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/declarationChecks/mulitpleVarargParameters.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("MultiDeclarationErrors.kt")
             public void testMultiDeclarationErrors() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/declarationChecks/MultiDeclarationErrors.kt");