Better diagnostics for conflicting overloads.

Skip declarations without sources in reporting, not when determining redeclaration groups:
this allows emitting informative diagnostics for incremental compilation.
Provide containing declaration with "kind", e.g., "package '<root>'", "class A", and so on.

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

@@ -296,7 +296,7 @@ public interface Errors {
 
     // Members
 
-    DiagnosticFactory2<KtDeclaration, CallableMemberDescriptor, CallableMemberDescriptor> CONFLICTING_OVERLOADS =
+    DiagnosticFactory2<KtDeclaration, CallableMemberDescriptor, DeclarationDescriptor> CONFLICTING_OVERLOADS =
             DiagnosticFactory2.create(ERROR, DECLARATION_SIGNATURE_OR_DEFAULT);
 
     DiagnosticFactory0<KtNamedDeclaration> NON_FINAL_MEMBER_IN_FINAL_CLASS = DiagnosticFactory0.create(WARNING, modifierSetPosition(

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

@@ -611,7 +611,8 @@ public class DefaultErrorMessages {
         MAP.put(MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED, "{0} must override {1} because it inherits multiple interface methods of it",
                 RENDER_CLASS_OR_OBJECT, FQ_NAMES_IN_TYPES);
 
-        MAP.put(CONFLICTING_OVERLOADS, "''{0}'' conflicts with another declaration: {1}", COMPACT_WITH_MODIFIERS, COMPACT_WITH_MODIFIERS);
+        MAP.put(CONFLICTING_OVERLOADS, "''{0}'' conflicts with another declaration in {1}", COMPACT_WITH_MODIFIERS,
+                DECLARATION_NAME_WITH_KIND);
 
         MAP.put(FUNCTION_EXPECTED, "Expression ''{0}''{1} cannot be invoked as a function. " +
                                    "The function '" + OperatorNameConventions.INVOKE.asString() + "()' is not found",

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/Renderers.kt

@@ -76,6 +76,19 @@ object Renderers {
 
     @JvmField val NAME: Renderer<Named> = Renderer { it.name.asString() }
 
+    @JvmField val DECLARATION_NAME_WITH_KIND: Renderer<DeclarationDescriptor> = Renderer {
+        val declarationKindWithSpace = when (it) {
+            is PackageFragmentDescriptor -> "package "
+            is ClassDescriptor -> "${it.renderKind()} "
+            is ConstructorDescriptor -> "constructor "
+            is PropertyGetterDescriptor -> "property getter "
+            is PropertySetterDescriptor -> "property setter "
+            is FunctionDescriptor -> "function "
+            else -> throw AssertionError("Unexpected declaration kind: $it")
+        }
+        "$declarationKindWithSpace'${it.name.asString()}'"
+    }
+
     @JvmField val NAME_OF_PARENT_OR_FILE: Renderer<DeclarationDescriptor> = Renderer {
         if (DescriptorUtils.isTopLevelDeclaration(it) && it is DeclarationDescriptorWithVisibility && it.visibility == Visibilities.PRIVATE) {
             "file"

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

@@ -52,7 +52,7 @@ public class OverloadResolver {
         MultiMap<ClassDescriptor, ConstructorDescriptor> inClasses = findConstructorsInNestedClasses(c);
 
         for (Map.Entry<KtClassOrObject, ClassDescriptorWithResolutionScopes> entry : c.getDeclaredClasses().entrySet()) {
-            checkOverloadsInAClass(entry.getValue(), entry.getKey(), inClasses.get(entry.getValue()));
+            checkOverloadsInAClass(entry.getValue(), inClasses.get(entry.getValue()));
         }
         checkOverloadsInPackages(c);
     }
@@ -88,27 +88,12 @@ public class OverloadResolver {
                 OverloadUtil.groupModulePackageMembersByFqName(c, overloadFilter);
 
         for (Map.Entry<FqNameUnsafe, Collection<CallableMemberDescriptor>> e : membersByName.entrySet()) {
-            FqNameUnsafe fqName = e.getKey().parent();
+            checkOverloadsInPackage(e.getValue());
-            checkOverloadsInPackage(e.getValue(), fqName);
         }
     }
 
-    private static String nameForErrorMessage(ClassDescriptor classDescriptor, KtClassOrObject jetClass) {
-        String name = jetClass.getName();
-        if (name != null) {
-            return name;
-        }
-        if (jetClass instanceof KtObjectDeclaration) {
-            // must be companion object
-            name = classDescriptor.getContainingDeclaration().getName().asString();
-            return "companion object " + name;
-        }
-        // safe
-        return "<unknown>";
-    }
-
     private void checkOverloadsInAClass(
-            ClassDescriptorWithResolutionScopes classDescriptor, KtClassOrObject klass,
+            ClassDescriptorWithResolutionScopes classDescriptor,
             Collection<ConstructorDescriptor> nestedClassConstructors
     ) {
         MultiMap<Name, CallableMemberDescriptor> functionsByName = MultiMap.create();
@@ -122,31 +107,24 @@ public class OverloadResolver {
         }
         
         for (Map.Entry<Name, Collection<CallableMemberDescriptor>> e : functionsByName.entrySet()) {
-            checkOverloadsInClass(e.getValue(), classDescriptor, klass);
+            checkOverloadsInClass(e.getValue());
         }
     }
     
-    private void checkOverloadsInPackage(
+    private void checkOverloadsInPackage(@NotNull Collection<CallableMemberDescriptor> members) {
-            @NotNull Collection<CallableMemberDescriptor> members,
-            @NotNull FqNameUnsafe packageFQN
-    ) {
         if (members.size() == 1) return;
 
         for (Collection<? extends CallableMemberDescriptor> redeclarationGroup : OverloadUtil.getPossibleRedeclarationGroups(members)) {
             Set<Pair<KtDeclaration, CallableMemberDescriptor>> redeclarations = findRedeclarations(redeclarationGroup);
             // TODO: don't render FQ name here, extract this logic to somewhere
-            reportRedeclarations(packageFQN.isRoot() ? "root package" : packageFQN.asString(), redeclarations);
+            reportRedeclarations(redeclarations);
         }
     }
 
-    private void checkOverloadsInClass(
+    private void checkOverloadsInClass(@NotNull Collection<CallableMemberDescriptor> members) {
-            @NotNull Collection<CallableMemberDescriptor> members,
-            @NotNull ClassDescriptor classDescriptor,
-            @NotNull KtClassOrObject ktClass
-    ) {
         if (members.size() == 1) return;
 
-        reportRedeclarations(nameForErrorMessage(classDescriptor, ktClass), findRedeclarations(members));
+        reportRedeclarations(findRedeclarations(members));
     }
 
     @NotNull
@@ -164,9 +142,7 @@ public class OverloadResolver {
                     }
 
                     KtDeclaration ktDeclaration = (KtDeclaration) DescriptorToSourceUtils.descriptorToDeclaration(member);
-                    if (ktDeclaration != null) {
+                    redeclarations.add(Pair.create(ktDeclaration, member));
-                        redeclarations.add(Pair.create(ktDeclaration, member));
-                    }
                 }
             }
         }
@@ -196,10 +172,7 @@ public class OverloadResolver {
         return file == null || file2 == null || file != file2;
     }
 
-    private void reportRedeclarations(
+    private void reportRedeclarations(@NotNull Set<Pair<KtDeclaration, CallableMemberDescriptor>> redeclarations) {
-            @NotNull String functionContainer,
-            @NotNull Set<Pair<KtDeclaration, CallableMemberDescriptor>> redeclarations
-    ) {
         if (redeclarations.isEmpty()) return;
 
         Iterator<Pair<KtDeclaration, CallableMemberDescriptor>> redeclarationsIterator = redeclarations.iterator();
@@ -210,6 +183,8 @@ public class OverloadResolver {
 
         for (Pair<KtDeclaration, CallableMemberDescriptor> redeclaration : redeclarations) {
             KtDeclaration ktDeclaration = redeclaration.getFirst();
+            if (ktDeclaration == null) continue;
+
             CallableMemberDescriptor memberDescriptor = redeclaration.getSecond();
 
             CallableMemberDescriptor redeclarationDescriptor;
@@ -227,7 +202,8 @@ public class OverloadResolver {
                 trace.report(Errors.REDECLARATION.on(ktDeclaration, memberDescriptor.getName().asString()));
             }
             else {
-                trace.report(Errors.CONFLICTING_OVERLOADS.on(ktDeclaration, memberDescriptor, redeclarationDescriptor));
+                trace.report(Errors.CONFLICTING_OVERLOADS.on(ktDeclaration, memberDescriptor,
+                                                             redeclarationDescriptor.getContainingDeclaration()));
             }
         }
     }

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyClassMemberScope.kt

@@ -108,7 +108,7 @@ open class LazyClassMemberScope(
 
             override fun conflict(fromSuper: CallableMemberDescriptor, fromCurrent: CallableMemberDescriptor) {
                 val declaration = DescriptorToSourceUtils.descriptorToDeclaration(fromCurrent) as? KtDeclaration ?: error("fromCurrent can not be a fake override")
-                trace.report(Errors.CONFLICTING_OVERLOADS.on(declaration, fromCurrent, fromSuper))
+                trace.report(Errors.CONFLICTING_OVERLOADS.on(declaration, fromCurrent, fromSuper.containingDeclaration))
             }
         })
         OverrideResolver.resolveUnknownVisibilities(result, trace)

compiler/testData/cli/jvm/conflictingOverloads.out

@@ -1,7 +1,7 @@
-compiler/testData/cli/jvm/conflictingOverloads.kt:1:1: error: 'public fun a(): kotlin.collections.List<kotlin.Int>' conflicts with another declaration: public fun a(): kotlin.collections.List<kotlin.String>
+compiler/testData/cli/jvm/conflictingOverloads.kt:1:1: error: 'public fun a(): kotlin.collections.List<kotlin.Int>' conflicts with another declaration in package '<root>'
 fun a(): List<Int> = null!!
 ^
-compiler/testData/cli/jvm/conflictingOverloads.kt:2:1: error: 'public fun a(): kotlin.collections.List<kotlin.String>' conflicts with another declaration: public fun a(): kotlin.collections.List<kotlin.Int>
+compiler/testData/cli/jvm/conflictingOverloads.kt:2:1: error: 'public fun a(): kotlin.collections.List<kotlin.String>' conflicts with another declaration in package '<root>'
 fun a(): List<String> = null!!
 ^
 COMPILATION_ERROR

idea/idea-analysis/src/org/jetbrains/kotlin/idea/highlighter/IdeErrorMessages.java

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.diagnostics.TypeMismatchDueToTypeProjectionsData;
 import org.jetbrains.kotlin.diagnostics.rendering.DefaultErrorMessages;
 import org.jetbrains.kotlin.diagnostics.rendering.DiagnosticFactoryToRendererMap;
 import org.jetbrains.kotlin.diagnostics.rendering.DiagnosticRenderer;
+import org.jetbrains.kotlin.diagnostics.rendering.Renderers;
 import org.jetbrains.kotlin.js.resolve.diagnostics.ErrorsJs;
 import org.jetbrains.kotlin.js.resolve.diagnostics.JsCallDataHtmlRenderer;
 import org.jetbrains.kotlin.renderer.DescriptorRenderer;
@@ -137,8 +138,8 @@ public class IdeErrorMessages {
 
         MAP.put(MANY_IMPL_MEMBER_NOT_IMPLEMENTED, "<html>{0} must override {1}<br />because it inherits many implementations of it</html>",
                 RENDER_CLASS_OR_OBJECT, DescriptorRenderer.HTML);
-        MAP.put(CONFLICTING_OVERLOADS, "<html>''{0}''<br />conflicts with another declaration: {1}</html>",
+        MAP.put(CONFLICTING_OVERLOADS, "<html>''{0}''<br />conflicts with another declaration in {1}</html>",
-                IdeRenderers.HTML_COMPACT_WITH_MODIFIERS, IdeRenderers.HTML_COMPACT_WITH_MODIFIERS);
+                IdeRenderers.HTML_COMPACT_WITH_MODIFIERS, Renderers.DECLARATION_NAME_WITH_KIND);
 
         MAP.put(RESULT_TYPE_MISMATCH, "<html>Function return type mismatch." +
                                       "<table><tr><td>Expected:</td><td>{1}</td></tr>" +

idea/testData/codeInsight/overrideImplement/ambiguousSuper.kt.after

@@ -1,5 +1,5 @@
-// ERROR: 'public open fun foo(): kotlin.Unit' conflicts with another declaration: public open fun foo(): kotlin.Unit
+// ERROR: 'public open fun foo(): kotlin.Unit' conflicts with another declaration in class 'C'
-// ERROR: 'public open fun foo(): kotlin.Unit' conflicts with another declaration: public open fun foo(): kotlin.Unit
+// ERROR: 'public open fun foo(): kotlin.Unit' conflicts with another declaration in class 'C'
 interface I {
     open fun foo(){}
 }

idea/testData/diagnosticMessage/conflictingOverloadsClass1.html

@@ -1,3 +1,3 @@
 <!-- conflictingOverloadsClass1 -->
 <html>
-'<b>public</b> <b>final</b> <b>fun</b> lol(x: kotlin.Int): kotlin.Int'<br />conflicts with another declaration: <b>public</b> <b>final</b> <b>fun</b> lol(y: kotlin.Int): kotlin.Int</html>
+'<b>public</b> <b>final</b> <b>fun</b> lol(x: kotlin.Int): kotlin.Int'<br />conflicts with another declaration in class 'conflictingOverloads'</html>

idea/testData/diagnosticMessage/conflictingOverloadsClass2.html

@@ -1,3 +1,3 @@
 <!-- conflictingOverloadsClass2 -->
 <html>
-'<b>public</b> <b>final</b> <b>fun</b> lol(y: kotlin.Int): kotlin.Int'<br />conflicts with another declaration: <b>public</b> <b>final</b> <b>fun</b> lol(x: kotlin.Int): kotlin.Int</html>
+'<b>public</b> <b>final</b> <b>fun</b> lol(y: kotlin.Int): kotlin.Int'<br />conflicts with another declaration in class 'conflictingOverloads'</html>

idea/testData/diagnosticMessage/conflictingOverloadsDefaultPackage1.txt

@@ -1,2 +1,2 @@
 <!-- conflictingOverloadsDefaultPackage1 -->
-'public fun foo(x: kotlin.Int): kotlin.Int' conflicts with another declaration: public fun foo(y: kotlin.Int): kotlin.Int
+'public fun foo(x: kotlin.Int): kotlin.Int' conflicts with another declaration in package '<root>'

idea/testData/diagnosticMessage/conflictingOverloadsDefaultPackage2.txt

@@ -1,2 +1,2 @@
 <!-- conflictingOverloadsDefaultPackage2 -->
-'public fun foo(y: kotlin.Int): kotlin.Int' conflicts with another declaration: public fun foo(x: kotlin.Int): kotlin.Int
+'public fun foo(y: kotlin.Int): kotlin.Int' conflicts with another declaration in package '<root>'

idea/testData/diagnosticMessage/constructorsRedeclaration1.txt

@@ -1,2 +1,2 @@
 <!-- constructorsRedeclaration1 -->
-'public constructor Element(x: kotlin.String)' conflicts with another declaration: public constructor Element(x: kotlin.String)
+'public constructor Element(x: kotlin.String)' conflicts with another declaration in class 'Element'

idea/testData/diagnosticMessage/constructorsRedeclaration2.txt

@@ -1,2 +1,2 @@
 <!-- constructorsRedeclaration2 -->
-'public constructor Element(x: kotlin.String)' conflicts with another declaration: public constructor Element(x: kotlin.String)
+'public constructor Element(x: kotlin.String)' conflicts with another declaration in class 'Element'

idea/testData/diagnosticMessage/constructorsRedeclarationTopLevel1.txt

@@ -1,2 +1,2 @@
 <!-- constructorsRedeclarationTopLevel1 -->
-'public fun Element(x: kotlin.String): kotlin.Unit' conflicts with another declaration: public constructor Element(x: kotlin.String)
+'public fun Element(x: kotlin.String): kotlin.Unit' conflicts with another declaration in class 'Element'

idea/testData/diagnosticMessage/constructorsRedeclarationTopLevel2.txt

@@ -1,2 +1,2 @@
 <!-- constructorsRedeclarationTopLevel2 -->
-'public constructor Element(x: kotlin.String)' conflicts with another declaration: public fun Element(x: kotlin.String): kotlin.Unit
+'public constructor Element(x: kotlin.String)' conflicts with another declaration in package '<root>'

jps-plugin/testData/incremental/classHierarchyAffected/secondaryConstructorAdded/build.log

@@ -5,7 +5,7 @@ Compiling files:
 src/A.kt
 End of files
 COMPILATION FAILED
-'public constructor A(x: kotlin.String)' conflicts with another declaration: public constructor A(x: kotlin.String)
+'public constructor A(x: kotlin.String)' conflicts with another declaration in package '<root>'
 
 
 Cleaning output files:

jps-plugin/testData/incremental/pureKotlin/funRedeclaration/build.log

@@ -6,4 +6,4 @@ Compiling files:
 src/fun2.kt
 End of files
 COMPILATION FAILED
-'public fun function(): kotlin.Unit' conflicts with another declaration: public fun function(): kotlin.Unit
+'public fun function(): kotlin.Unit' conflicts with another declaration in package 'test'

jps-plugin/testData/incremental/pureKotlin/funVsConstructorOverloadConflict/build.log

@@ -6,4 +6,4 @@ Compiling files:
 src/fun2.kt
 End of files
 COMPILATION FAILED
-'public constructor function()' conflicts with another declaration: public constructor function()
+'public constructor function()' conflicts with another declaration in package 'test'