Improved error message for 'nested class should be qualified'

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java

@@ -602,7 +602,7 @@ public interface Errors {
     DiagnosticFactory1<JetSimpleNameExpression, TypeParameterDescriptor> TYPE_PARAMETER_IS_NOT_AN_EXPRESSION = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory1<JetSimpleNameExpression, TypeParameterDescriptor> TYPE_PARAMETER_ON_LHS_OF_DOT = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory1<JetExpression, ClassDescriptor> NESTED_CLASS_ACCESSED_VIA_INSTANCE_REFERENCE = DiagnosticFactory1.create(ERROR);
-    DiagnosticFactory1<JetExpression, ClassDescriptor> NESTED_CLASS_SHOULD_BE_QUALIFIED = DiagnosticFactory1.create(ERROR);
+    DiagnosticFactory2<JetExpression, ClassDescriptor, String> NESTED_CLASS_SHOULD_BE_QUALIFIED = DiagnosticFactory2.create(ERROR);
 
     DiagnosticFactory1<PsiElement, ClassDescriptor> INACCESSIBLE_OUTER_CLASS_EXPRESSION = DiagnosticFactory1.create(ERROR);
     DiagnosticFactory0<JetClass> NESTED_CLASS_NOT_ALLOWED = DiagnosticFactory0.create(ERROR, DECLARATION_NAME);

compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/rendering/DefaultErrorMessages.java

@@ -262,7 +262,7 @@ public class DefaultErrorMessages {
         MAP.put(TYPE_PARAMETER_ON_LHS_OF_DOT, "Type parameter ''{0}'' cannot have or inherit a class object, so it cannot be on the left hand side of dot", NAME);
         MAP.put(NO_GENERICS_IN_SUPERTYPE_SPECIFIER, "Generic arguments of the base type must be specified");
         MAP.put(NESTED_CLASS_ACCESSED_VIA_INSTANCE_REFERENCE, "Nested {0} accessed via instance reference", RENDER_CLASS_OR_OBJECT_NAME);
-        MAP.put(NESTED_CLASS_SHOULD_BE_QUALIFIED, "Nested {0} should be qualified", RENDER_CLASS_OR_OBJECT_NAME);
+        MAP.put(NESTED_CLASS_SHOULD_BE_QUALIFIED, "Nested {0} should be qualified as ''{1}''", RENDER_CLASS_OR_OBJECT_NAME, TO_STRING);
 
         MAP.put(INACCESSIBLE_OUTER_CLASS_EXPRESSION, "Expression is inaccessible from a nested class ''{0}'', use ''inner'' keyword to make the class inner", NAME);
         MAP.put(NESTED_CLASS_NOT_ALLOWED, "Nested class is not allowed here, use ''inner'' keyword to make the class inner");

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/tasks/AbstractTracingStrategy.java

@@ -25,6 +25,8 @@ import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingTrace;
 import org.jetbrains.jet.lang.resolve.calls.inference.*;
 import org.jetbrains.jet.lang.resolve.calls.model.ResolvedCall;
+import org.jetbrains.jet.lang.resolve.descriptorUtil.DescriptorUtilPackage;
+import org.jetbrains.jet.lang.resolve.name.FqName;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ExpressionReceiver;
 import org.jetbrains.jet.lang.resolve.scopes.receivers.ReceiverValue;
@@ -39,6 +41,7 @@ import java.util.List;
 
 import static org.jetbrains.jet.lang.diagnostics.Errors.*;
 import static org.jetbrains.jet.lang.resolve.BindingContext.AMBIGUOUS_REFERENCE_TARGET;
+import static org.jetbrains.jet.lang.resolve.DescriptorUtils.getFqNameFromTopLevelClass;
 import static org.jetbrains.jet.lang.types.TypeUtils.noExpectedType;
 
 public abstract class AbstractTracingStrategy implements TracingStrategy {
@@ -134,7 +137,15 @@ public abstract class AbstractTracingStrategy implements TracingStrategy {
             @NotNull ExplicitReceiverKind explicitReceiverKind
     ) {
         if (explicitReceiverKind == ExplicitReceiverKind.NO_EXPLICIT_RECEIVER) {
-            trace.report(NESTED_CLASS_SHOULD_BE_QUALIFIED.on(reference, classDescriptor));
+            String qualifiedName;
+            FqName fqName = getFqNameFromTopLevelClass(DescriptorUtilPackage.getImportableDescriptor(classDescriptor));
+            if (reference.getParent() instanceof JetCallableReferenceExpression) {
+                qualifiedName = fqName.parent() + "::" + classDescriptor.getName();
+            }
+            else {
+                qualifiedName = fqName.asString();
+            }
+            trace.report(NESTED_CLASS_SHOULD_BE_QUALIFIED.on(reference, classDescriptor, qualifiedName));
         }
         else {
             trace.report(NESTED_CLASS_ACCESSED_VIA_INSTANCE_REFERENCE.on(reference, classDescriptor));

compiler/frontend/src/org/jetbrains/jet/lang/resolve/scopes/receivers/Qualifier.kt

@@ -34,13 +34,13 @@ import org.jetbrains.jet.lang.descriptors.TypeParameterDescriptor
 import org.jetbrains.jet.lang.diagnostics.Errors.*
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor
 import org.jetbrains.jet.lang.descriptors.ConstructorDescriptor
-import org.jetbrains.jet.lang.descriptors.impl.PackageFragmentDescriptorImpl
 import org.jetbrains.jet.lang.types.expressions.ExpressionTypingContext
 import org.jetbrains.jet.lang.psi.psiUtil.getTopmostParentQualifiedExpressionForSelector
 import org.jetbrains.jet.lang.resolve.descriptorUtil.getClassObjectReferenceTarget
 import org.jetbrains.jet.lang.psi.JetExpression
 import org.jetbrains.jet.lang.resolve.bindingContextUtil.recordScopeAndDataFlowInfo
 import kotlin.properties.Delegates
+import org.jetbrains.jet.lang.descriptors.PackageFragmentDescriptor
 
 public trait Qualifier {
 
@@ -168,7 +168,7 @@ private fun QualifierReceiver.resolveReferenceTarget(selector: DeclarationDescri
         else -> selector?.getContainingDeclaration()
     }
 
-    if (packageView != null && (containingDeclaration is PackageFragmentDescriptorImpl || containingDeclaration is PackageViewDescriptor)
+    if (packageView != null && (containingDeclaration is PackageFragmentDescriptor || containingDeclaration is PackageViewDescriptor)
             && getFqName(packageView) == getFqName(containingDeclaration)) {
         return packageView
     }

core/descriptors/src/org/jetbrains/jet/lang/resolve/DescriptorUtils.java

@@ -102,14 +102,8 @@ public class DescriptorUtils {
 
     @NotNull
     private static FqNameUnsafe getFqNameUnsafe(@NotNull DeclarationDescriptor descriptor) {
-        DeclarationDescriptor containingDeclaration = descriptor.getContainingDeclaration();
+        DeclarationDescriptor containingDeclaration = getContainingDeclarationSkippingClassObjects(descriptor);
-
+        assert containingDeclaration != null : "Not package/module descriptor doesn't have containing declaration: " + descriptor;
-        if (containingDeclaration instanceof ClassDescriptor && ((ClassDescriptor) containingDeclaration).getKind() == ClassKind.CLASS_OBJECT) {
-            DeclarationDescriptor classOfClassObject = containingDeclaration.getContainingDeclaration();
-            assert classOfClassObject != null;
-            return getFqName(classOfClassObject).child(descriptor.getName());
-        }
-
         return getFqName(containingDeclaration).child(descriptor.getName());
     }
 
@@ -117,6 +111,22 @@ public class DescriptorUtils {
         return descriptor.getContainingDeclaration() instanceof PackageFragmentDescriptor;
     }
 
+    @Nullable
+    private static DeclarationDescriptor getContainingDeclarationSkippingClassObjects(@NotNull DeclarationDescriptor descriptor) {
+        DeclarationDescriptor containingDeclaration = descriptor.getContainingDeclaration();
+        return isClassObject(containingDeclaration) ? containingDeclaration.getContainingDeclaration() : containingDeclaration;
+    }
+
+    @NotNull
+    public static FqName getFqNameFromTopLevelClass(@NotNull DeclarationDescriptor descriptor) {
+        DeclarationDescriptor containingDeclaration = getContainingDeclarationSkippingClassObjects(descriptor);
+        Name name = descriptor.getName();
+        if (!(containingDeclaration instanceof ClassDescriptor)) {
+            return FqName.topLevel(name);
+        }
+        return getFqNameFromTopLevelClass(containingDeclaration).child(name);
+    }
+
     // WARNING! Don't use this method in JVM backend, use JvmCodegenUtil.isCallInsideSameModuleAsDeclared() instead.
     // The latter handles compilation against compiled part of our module correctly.
     public static boolean areInSameModule(@NotNull DeclarationDescriptor first, @NotNull DeclarationDescriptor second) {
@@ -202,7 +212,7 @@ public class DescriptorUtils {
         return descriptor instanceof AnonymousFunctionDescriptor;
     }
 
-    public static boolean isClassObject(@NotNull DeclarationDescriptor descriptor) {
+    public static boolean isClassObject(@Nullable DeclarationDescriptor descriptor) {
         return isKindOf(descriptor, ClassKind.CLASS_OBJECT);
     }
 

core/descriptors/src/org/jetbrains/jet/lang/resolve/DescriptorUtils.kt

@@ -20,6 +20,9 @@ import org.jetbrains.jet.lang.descriptors.ClassDescriptor
 import org.jetbrains.jet.lang.descriptors.ClassKind.ENUM_ENTRY
 import org.jetbrains.jet.lang.descriptors.ClassKind.ENUM_CLASS
 import org.jetbrains.jet.lang.descriptors.ClassKind.OBJECT
+import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor
+import org.jetbrains.jet.lang.descriptors.ConstructorDescriptor
+import org.jetbrains.jet.lang.resolve.DescriptorUtils
 
 
 public fun ClassDescriptor.getClassObjectReferenceTarget(): ClassDescriptor {
@@ -28,3 +31,6 @@ public fun ClassDescriptor.getClassObjectReferenceTarget(): ClassDescriptor {
 }
 
 public fun ClassDescriptor.hasSyntheticClassObject(): Boolean = getKind() in setOf(ENUM_ENTRY, ENUM_CLASS, OBJECT)
+
+public fun DeclarationDescriptor.getImportableDescriptor(): DeclarationDescriptor =
+        if (this is ConstructorDescriptor || DescriptorUtils.isClassObject(this)) getContainingDeclaration()!! else this

idea/src/org/jetbrains/jet/plugin/imports/ImportsUtils.kt

@@ -27,9 +27,7 @@ import org.jetbrains.jet.lang.psi.JetSimpleNameExpression
 import org.jetbrains.jet.lang.psi.psiUtil.getReceiverExpression
 import com.intellij.psi.PsiElement
 import org.jetbrains.jet.lang.types.JetType
-
+import org.jetbrains.jet.lang.resolve.descriptorUtil.getImportableDescriptor
-private fun DeclarationDescriptor.getImportableDescriptor() =
-        if (this is ConstructorDescriptor || DescriptorUtils.isClassObject(this)) getContainingDeclaration()!! else this
 
 public val DeclarationDescriptor.importableFqName: FqName?
     get() {

idea/testData/diagnosticMessage/nestedClassShouldBeQualified.kt

@@ -0,0 +1,38 @@
+// !DIAGNOSTICS_NUMBER: 5
+// !DIAGNOSTICS: NESTED_CLASS_SHOULD_BE_QUALIFIED
+
+package p
+
+class A {
+    class B {
+        class Nested
+    }
+}
+
+fun A.B.test() {
+    Nested()
+    ::Nested
+}
+
+class C {
+    class object {
+        class D {
+            class Nested
+        }
+    }
+}
+
+fun C.D.text() {
+    Nested()
+    ::Nested
+}
+
+class E {
+    class F {
+        class object
+    }
+}
+
+fun E.test() {
+    F
+}

idea/testData/diagnosticMessage/nestedClassShouldBeQualified1.txt

@@ -0,0 +1,2 @@
+<!-- nestedClassShouldBeQualified1 -->
+Nested class 'Nested' should be qualified as 'A.B.Nested'

idea/testData/diagnosticMessage/nestedClassShouldBeQualified2.txt

@@ -0,0 +1,2 @@
+<!-- nestedClassShouldBeQualified2 -->
+Nested class 'Nested' should be qualified as 'A.B::Nested'

idea/testData/diagnosticMessage/nestedClassShouldBeQualified3.txt

@@ -0,0 +1,2 @@
+<!-- nestedClassShouldBeQualified3 -->
+Nested class 'Nested' should be qualified as 'C.D.Nested'

idea/testData/diagnosticMessage/nestedClassShouldBeQualified4.txt

@@ -0,0 +1,2 @@
+<!-- nestedClassShouldBeQualified4 -->
+Nested class 'Nested' should be qualified as 'C.D::Nested'

idea/testData/diagnosticMessage/nestedClassShouldBeQualified5.txt

@@ -0,0 +1,2 @@
+<!-- nestedClassShouldBeQualified5 -->
+Nested class object of 'F' should be qualified as 'E.F'

idea/tests/org/jetbrains/jet/plugin/highlighter/DiagnosticMessageTestGenerated.java

@@ -103,6 +103,11 @@ public class DiagnosticMessageTestGenerated extends AbstractDiagnosticMessageTes
         doTest("idea/testData/diagnosticMessage/nestedClassAcessedViaInstanceReference.kt");
     }
     
+    @TestMetadata("nestedClassShouldBeQualified.kt")
+    public void testNestedClassShouldBeQualified() throws Exception {
+        doTest("idea/testData/diagnosticMessage/nestedClassShouldBeQualified.kt");
+    }
+    
     @TestMetadata("noneApplicable.kt")
     public void testNoneApplicable() throws Exception {
         doTest("idea/testData/diagnosticMessage/noneApplicable.kt");