use MainFunctionDetector in order to check for main function

compiler/backend/src/org/jetbrains/kotlin/codegen/state/BuilderFactoryForDuplicateSignatureDiagnostics.kt

@@ -27,12 +27,12 @@ import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor.Kind.FAKE_OVERR
 import org.jetbrains.kotlin.diagnostics.DiagnosticSink
 import org.jetbrains.kotlin.fileClasses.JvmFileClassesProvider
 import org.jetbrains.kotlin.fileClasses.isInsideJvmMultifileClassFile
+import org.jetbrains.kotlin.idea.MainFunctionDetector
 import org.jetbrains.kotlin.load.java.descriptors.SamAdapterDescriptor
 import org.jetbrains.kotlin.load.kotlin.incremental.components.IncrementalCache
-import org.jetbrains.kotlin.psi.JetDeclaration
+import org.jetbrains.kotlin.psi.JetNamedFunction
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
-import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.*
 import org.jetbrains.kotlin.utils.addIfNotNull
 import java.util.*
@@ -54,6 +54,8 @@ class BuilderFactoryForDuplicateSignatureDiagnostics(
     // Avoid errors when some classes are not loaded for some reason
     private val typeMapper = JetTypeMapper(bindingContext, ClassBuilderMode.LIGHT_CLASSES, fileClassesProvider, incrementalCache, moduleName)
 
+    private val mainFunctionDetector = MainFunctionDetector(bindingContext)
+
     override fun handleClashingSignatures(data: ConflictingJvmDeclarationsData) {
         val noOwnImplementations = data.signatureOrigins.all { it.originKind in EXTERNAL_SOURCES_KINDS }
 
@@ -66,11 +68,7 @@ class BuilderFactoryForDuplicateSignatureDiagnostics(
                 var element = origin.element
 
                 // TODO Remove this code after dropping package facades
-                val descriptor = origin.descriptor
-                if (descriptor != null && element is JetDeclaration && DescriptorUtils.isTopLevelMainFunction(descriptor) &&
-                        !element.isInsideJvmMultifileClassFile()) {
-                    return
-                }
+                if (element is JetNamedFunction && mainFunctionDetector.isMain(element) && !element.isInsideJvmMultifileClassFile()) return
 
                 if (element == null || origin.originKind in EXTERNAL_SOURCES_KINDS) {
                     element = data.classOrigin.element

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

@@ -17,15 +17,14 @@
 package org.jetbrains.kotlin.resolve
 
 import com.intellij.psi.PsiElement
-import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor.Kind.DECLARATION
 import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor.Kind.SYNTHESIZED
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithSource
-import org.jetbrains.kotlin.descriptors.PropertyAccessorDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor
+import org.jetbrains.kotlin.idea.MainFunctionDetector
 import org.jetbrains.kotlin.psi.JetAnnotationEntry
 import org.jetbrains.kotlin.psi.JetFile
+import org.jetbrains.kotlin.psi.JetNamedFunction
 import org.jetbrains.kotlin.resolve.source.getPsi
 import java.util.ArrayList
 
@@ -81,6 +80,16 @@ public object DescriptorToSourceUtils {
         return declaration.getContainingFile() as? JetFile
     }
 
+    @JvmStatic
+    public fun isTopLevelMainFunction(declarationDescriptor: DeclarationDescriptor, mainFunctionDetector: MainFunctionDetector): Boolean {
+        if (declarationDescriptor !is FunctionDescriptor ||
+            !DescriptorUtils.isTopLevelDeclaration(declarationDescriptor) ||
+            declarationDescriptor.name.asString() != "main") return false
+
+        val element = descriptorToDeclaration(declarationDescriptor)
+        return element is JetNamedFunction && mainFunctionDetector.isMain(element)
+    }
+
     private fun findTopLevelParent(declarationDescriptor: DeclarationDescriptor): DeclarationDescriptor? {
         var descriptor: DeclarationDescriptor? = declarationDescriptor
         if (declarationDescriptor is PropertyAccessorDescriptor) {

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

@@ -22,6 +22,7 @@ import com.intellij.util.containers.MultiMap;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.diagnostics.Errors;
+import org.jetbrains.kotlin.idea.MainFunctionDetector;
 import org.jetbrains.kotlin.name.FqNameUnsafe;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.psi.JetClassOrObject;
@@ -37,9 +38,11 @@ import static org.jetbrains.kotlin.resolve.DescriptorUtils.getFqName;
 
 public class OverloadResolver {
     @NotNull private final BindingTrace trace;
+    @NotNull private final MainFunctionDetector mainFunctionDetector;
 
     public OverloadResolver(@NotNull BindingTrace trace) {
         this.trace = trace;
+        mainFunctionDetector = new MainFunctionDetector(trace.getBindingContext());
     }
 
     public void process(@NotNull BodiesResolveContext c) {
@@ -195,7 +198,7 @@ public class OverloadResolver {
             @NotNull Set<Pair<JetDeclaration, CallableMemberDescriptor>> redeclarations) {
         for (Pair<JetDeclaration, CallableMemberDescriptor> redeclaration : redeclarations) {
             CallableMemberDescriptor memberDescriptor = redeclaration.getSecond();
-            if (DescriptorUtils.isTopLevelMainFunction(memberDescriptor)) break;
+            if (DescriptorToSourceUtils.isTopLevelMainFunction(memberDescriptor, mainFunctionDetector)) return;
 
             JetDeclaration jetDeclaration = redeclaration.getFirst();
             if (memberDescriptor instanceof PropertyDescriptor) {

core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.java

@@ -630,21 +630,6 @@ public class DescriptorUtils {
         return SourceFile.NO_SOURCE_FILE;
     }
 
-    public static boolean isTopLevelMainFunction(@NotNull DeclarationDescriptor descriptor) {
-        if (!(descriptor instanceof FunctionDescriptor) ||
-            !isTopLevelDeclaration(descriptor) ||
-            !"main".equals(descriptor.getName().asString())) return false;
-
-        FunctionDescriptor functionDescriptor = (FunctionDescriptor) descriptor;
-        List<ValueParameterDescriptor> valueParameterDescriptors = functionDescriptor.getValueParameters();
-        if (valueParameterDescriptors.size() != 1) return false;
-
-        JetType type = valueParameterDescriptors.get(0).getType();
-
-        return KotlinBuiltIns.isArray(type) && type.getArguments().size() == 1 && KotlinBuiltIns.isString(type.getArguments().get(0).getType());
-    }
-
-
     private static void getSubPackagesFqNames(PackageViewDescriptor packageView, Set<FqName> result) {
         FqName fqName = packageView.getFqName();
         if (!fqName.isRoot()) {