diff --git a/compiler/cli/src/org/jetbrains/jet/compiler/CompileSession.java b/compiler/cli/src/org/jetbrains/jet/compiler/CompileSession.java
index 8b6c4a8d1f9..952f4cdb2c7 100644
--- a/compiler/cli/src/org/jetbrains/jet/compiler/CompileSession.java
+++ b/compiler/cli/src/org/jetbrains/jet/compiler/CompileSession.java
@@ -36,7 +36,7 @@ import org.jetbrains.jet.lang.descriptors.ClassOrNamespaceDescriptor;
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor;
 import org.jetbrains.jet.lang.descriptors.ModuleDescriptor;
 import org.jetbrains.jet.lang.diagnostics.Diagnostic;
-import org.jetbrains.jet.lang.diagnostics.DiagnosticFactory;
+import org.jetbrains.jet.lang.diagnostics.SimpleDiagnosticFactory;
 import org.jetbrains.jet.lang.diagnostics.DiagnosticUtils;
 import org.jetbrains.jet.lang.diagnostics.Severity;
 import org.jetbrains.jet.lang.psi.JetFile;
@@ -139,7 +139,7 @@ public class CompileSession {
                 public void visitErrorElement(PsiErrorElement element) {
                     String description = element.getErrorDescription();
                     String message = StringUtil.isEmpty(description) ? "Syntax error" : description;
-                    Diagnostic diagnostic = DiagnosticFactory.create(Severity.ERROR, message).on(element);
+                    Diagnostic diagnostic = SimpleDiagnosticFactory.create(Severity.ERROR, message).on(element);
                     reportDiagnostic(messageCollector, diagnostic);
                 }
             });
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java
index e6ba102a7eb..991f03e296c 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/Errors.java
@@ -86,57 +86,90 @@ public interface Errors {
     DiagnosticFactory1<PsiElement, JetKeywordToken> ILLEGAL_MODIFIER = DiagnosticFactory1.create(ERROR, "Illegal modifier ''{0}''");
 
     DiagnosticFactory2<PsiElement, JetKeywordToken, JetKeywordToken> REDUNDANT_MODIFIER = DiagnosticFactory2.create(Severity.WARNING, "Modifier {0} is redundant because {1} is present");
-    DiagnosticFactory<JetModifierListOwner> ABSTRACT_MODIFIER_IN_TRAIT = DiagnosticFactory.create(WARNING, "Modifier ''{0}'' is redundant in trait", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
-    DiagnosticFactory<JetModifierListOwner> OPEN_MODIFIER_IN_TRAIT = DiagnosticFactory.create(WARNING, "Modifier ''{0}'' is redundant in trait", PositioningStrategies.positionModifier(JetTokens.OPEN_KEYWORD));
-    DiagnosticFactory<PsiElement> REDUNDANT_MODIFIER_IN_GETTER = DiagnosticFactory.create(WARNING, "Visibility modifiers are redundant in getter");
-    DiagnosticFactory<PsiElement> TRAIT_CAN_NOT_BE_FINAL = DiagnosticFactory.create(ERROR, "Trait can not be final");
-    DiagnosticFactory<JetExpression> TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM = DiagnosticFactory.create(ERROR, "Type checking has run into a recursive problem. Easiest workaround: specify types of your declarations explicitly"); // TODO: message
-    DiagnosticFactory<JetReturnExpression> RETURN_NOT_ALLOWED = DiagnosticFactory.create(ERROR, "'return' is not allowed here");
-    DiagnosticFactory<JetTypeProjection> PROJECTION_IN_IMMEDIATE_ARGUMENT_TO_SUPERTYPE = DiagnosticFactory.create(ERROR, "Projections are not allowed for immediate arguments of a supertype", new PositioningStrategy<JetTypeProjection>() {
-        @NotNull
-        @Override
-        public List<TextRange> mark(@NotNull JetTypeProjection element) {
-            return markNode(element.getProjectionNode());
-        }
-    });
-    DiagnosticFactory<JetSimpleNameExpression> LABEL_NAME_CLASH = DiagnosticFactory.create(WARNING, "There is more than one label with such a name in this scope");
-    DiagnosticFactory<JetSimpleNameExpression> EXPRESSION_EXPECTED_NAMESPACE_FOUND = DiagnosticFactory.create(ERROR, "Expression expected, but a namespace name found");
+    SimpleDiagnosticFactory<JetModifierListOwner> ABSTRACT_MODIFIER_IN_TRAIT = SimpleDiagnosticFactory
+            .create(WARNING, "Modifier ''{0}'' is redundant in trait", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
+    SimpleDiagnosticFactory<JetModifierListOwner> OPEN_MODIFIER_IN_TRAIT = SimpleDiagnosticFactory
+            .create(WARNING, "Modifier ''{0}'' is redundant in trait", PositioningStrategies.positionModifier(JetTokens.OPEN_KEYWORD));
+    SimpleDiagnosticFactory<PsiElement>
+            REDUNDANT_MODIFIER_IN_GETTER = SimpleDiagnosticFactory.create(WARNING, "Visibility modifiers are redundant in getter");
+    SimpleDiagnosticFactory<PsiElement> TRAIT_CAN_NOT_BE_FINAL = SimpleDiagnosticFactory.create(ERROR, "Trait can not be final");
+    SimpleDiagnosticFactory<JetExpression> TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM = SimpleDiagnosticFactory.create(ERROR,
+                                                                                                                       "Type checking has run into a recursive problem. Easiest workaround: specify types of your declarations explicitly"); // TODO: message
+    SimpleDiagnosticFactory<JetReturnExpression> RETURN_NOT_ALLOWED = SimpleDiagnosticFactory.create(ERROR, "'return' is not allowed here");
+    SimpleDiagnosticFactory<JetTypeProjection> PROJECTION_IN_IMMEDIATE_ARGUMENT_TO_SUPERTYPE = SimpleDiagnosticFactory
+            .create(ERROR, "Projections are not allowed for immediate arguments of a supertype",
+                    new PositioningStrategy<JetTypeProjection>() {
+                        @NotNull
+                        @Override
+                        public List<TextRange> mark(@NotNull JetTypeProjection element) {
+                            return markNode(element.getProjectionNode());
+                        }
+                    });
+    SimpleDiagnosticFactory<JetSimpleNameExpression>
+            LABEL_NAME_CLASH = SimpleDiagnosticFactory.create(WARNING, "There is more than one label with such a name in this scope");
+    SimpleDiagnosticFactory<JetSimpleNameExpression>
+            EXPRESSION_EXPECTED_NAMESPACE_FOUND = SimpleDiagnosticFactory.create(ERROR, "Expression expected, but a namespace name found");
 
     DiagnosticFactory1<JetSimpleNameExpression, DeclarationDescriptor> CANNOT_IMPORT_FROM_ELEMENT = DiagnosticFactory1.create(ERROR, "Cannot import from ''{0}''", NAME);
     DiagnosticFactory1<JetSimpleNameExpression, DeclarationDescriptor> CANNOT_BE_IMPORTED = DiagnosticFactory1.create(ERROR, "Cannot import ''{0}'', functions and properties can be imported only from packages", NAME);
-    DiagnosticFactory<JetExpression> USELESS_HIDDEN_IMPORT = DiagnosticFactory.create(WARNING, "Useless import, it is hidden further");
-    DiagnosticFactory<JetExpression> USELESS_SIMPLE_IMPORT = DiagnosticFactory.create(WARNING, "Useless import, does nothing");
+    SimpleDiagnosticFactory<JetExpression>
+            USELESS_HIDDEN_IMPORT = SimpleDiagnosticFactory.create(WARNING, "Useless import, it is hidden further");
+    SimpleDiagnosticFactory<JetExpression> USELESS_SIMPLE_IMPORT = SimpleDiagnosticFactory.create(WARNING, "Useless import, does nothing");
 
-    DiagnosticFactory<JetParameter> CANNOT_INFER_PARAMETER_TYPE = DiagnosticFactory.create(ERROR, "Cannot infer a type for this parameter. To specify it explicitly use the {(p : Type) => ...} notation");
+    SimpleDiagnosticFactory<JetParameter> CANNOT_INFER_PARAMETER_TYPE = SimpleDiagnosticFactory
+            .create(ERROR, "Cannot infer a type for this parameter. To specify it explicitly use the {(p : Type) => ...} notation");
 
-    DiagnosticFactory<JetElement> NO_BACKING_FIELD_ABSTRACT_PROPERTY = DiagnosticFactory.create(ERROR, "This property doesn't have a backing field, because it's abstract");
-    DiagnosticFactory<JetElement> NO_BACKING_FIELD_CUSTOM_ACCESSORS = DiagnosticFactory.create(ERROR, "This property doesn't have a backing field, because it has custom accessors without reference to the backing field");
-    DiagnosticFactory<JetElement> INACCESSIBLE_BACKING_FIELD = DiagnosticFactory.create(ERROR, "The backing field is not accessible here");
-    DiagnosticFactory<JetElement> NOT_PROPERTY_BACKING_FIELD = DiagnosticFactory.create(ERROR, "The referenced variable is not a property and doesn't have backing field");
+    SimpleDiagnosticFactory<JetElement> NO_BACKING_FIELD_ABSTRACT_PROPERTY = SimpleDiagnosticFactory
+            .create(ERROR, "This property doesn't have a backing field, because it's abstract");
+    SimpleDiagnosticFactory<JetElement> NO_BACKING_FIELD_CUSTOM_ACCESSORS = SimpleDiagnosticFactory.create(ERROR,
+                                                                                                           "This property doesn't have a backing field, because it has custom accessors without reference to the backing field");
+    SimpleDiagnosticFactory<JetElement>
+            INACCESSIBLE_BACKING_FIELD = SimpleDiagnosticFactory.create(ERROR, "The backing field is not accessible here");
+    SimpleDiagnosticFactory<JetElement> NOT_PROPERTY_BACKING_FIELD = SimpleDiagnosticFactory
+            .create(ERROR, "The referenced variable is not a property and doesn't have backing field");
 
-    DiagnosticFactory<PsiElement> MIXING_NAMED_AND_POSITIONED_ARGUMENTS = DiagnosticFactory.create(ERROR, "Mixing named and positioned arguments in not allowed");
-    DiagnosticFactory<JetReferenceExpression> ARGUMENT_PASSED_TWICE = DiagnosticFactory.create(ERROR, "An argument is already passed for this parameter");
+    SimpleDiagnosticFactory<PsiElement> MIXING_NAMED_AND_POSITIONED_ARGUMENTS = SimpleDiagnosticFactory
+            .create(ERROR, "Mixing named and positioned arguments in not allowed");
+    SimpleDiagnosticFactory<JetReferenceExpression>
+            ARGUMENT_PASSED_TWICE = SimpleDiagnosticFactory.create(ERROR, "An argument is already passed for this parameter");
     UnresolvedReferenceDiagnosticFactory NAMED_PARAMETER_NOT_FOUND = UnresolvedReferenceDiagnosticFactory.create("Cannot find a parameter with this name");
-    DiagnosticFactory<JetExpression> VARARG_OUTSIDE_PARENTHESES = DiagnosticFactory.create(ERROR, "Passing value as a vararg is only allowed inside a parenthesized argument list");
-    DiagnosticFactory<LeafPsiElement> NON_VARARG_SPREAD = DiagnosticFactory.create(ERROR, "The spread operator (*foo) may only be applied in a vararg position");
+    SimpleDiagnosticFactory<JetExpression> VARARG_OUTSIDE_PARENTHESES = SimpleDiagnosticFactory
+            .create(ERROR, "Passing value as a vararg is only allowed inside a parenthesized argument list");
+    SimpleDiagnosticFactory<LeafPsiElement>
+            NON_VARARG_SPREAD = SimpleDiagnosticFactory.create(ERROR, "The spread operator (*foo) may only be applied in a vararg position");
 
-    DiagnosticFactory<JetExpression> MANY_FUNCTION_LITERAL_ARGUMENTS = DiagnosticFactory.create(ERROR, "Only one function literal is allowed outside a parenthesized argument list");
-    DiagnosticFactory<PsiElement> PROPERTY_WITH_NO_TYPE_NO_INITIALIZER = DiagnosticFactory.create(ERROR, "This property must either have a type annotation or be initialized");
+    SimpleDiagnosticFactory<JetExpression> MANY_FUNCTION_LITERAL_ARGUMENTS = SimpleDiagnosticFactory
+            .create(ERROR, "Only one function literal is allowed outside a parenthesized argument list");
+    SimpleDiagnosticFactory<PsiElement> PROPERTY_WITH_NO_TYPE_NO_INITIALIZER = SimpleDiagnosticFactory
+            .create(ERROR, "This property must either have a type annotation or be initialized");
 
-    DiagnosticFactory<JetModifierListOwner> ABSTRACT_PROPERTY_IN_PRIMARY_CONSTRUCTOR_PARAMETERS = DiagnosticFactory.create(ERROR, "This property cannot be declared abstract", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
-    DiagnosticFactory<JetProperty> ABSTRACT_PROPERTY_NOT_IN_CLASS = DiagnosticFactory.create(ERROR, "A property may be abstract only when defined in a class or trait", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
-    DiagnosticFactory<JetExpression> ABSTRACT_PROPERTY_WITH_INITIALIZER = DiagnosticFactory.create(ERROR, "Property with initializer cannot be abstract");
-    DiagnosticFactory<JetPropertyAccessor> ABSTRACT_PROPERTY_WITH_GETTER = DiagnosticFactory.create(ERROR, "Property with getter implementation cannot be abstract");
-    DiagnosticFactory<JetPropertyAccessor> ABSTRACT_PROPERTY_WITH_SETTER = DiagnosticFactory.create(ERROR, "Property with setter implementation cannot be abstract");
+    SimpleDiagnosticFactory<JetModifierListOwner> ABSTRACT_PROPERTY_IN_PRIMARY_CONSTRUCTOR_PARAMETERS = SimpleDiagnosticFactory
+            .create(ERROR, "This property cannot be declared abstract", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
+    SimpleDiagnosticFactory<JetProperty> ABSTRACT_PROPERTY_NOT_IN_CLASS = SimpleDiagnosticFactory
+            .create(ERROR, "A property may be abstract only when defined in a class or trait",
+                    PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
+    SimpleDiagnosticFactory<JetExpression>
+            ABSTRACT_PROPERTY_WITH_INITIALIZER = SimpleDiagnosticFactory.create(ERROR, "Property with initializer cannot be abstract");
+    SimpleDiagnosticFactory<JetPropertyAccessor>
+            ABSTRACT_PROPERTY_WITH_GETTER = SimpleDiagnosticFactory.create(ERROR, "Property with getter implementation cannot be abstract");
+    SimpleDiagnosticFactory<JetPropertyAccessor>
+            ABSTRACT_PROPERTY_WITH_SETTER = SimpleDiagnosticFactory.create(ERROR, "Property with setter implementation cannot be abstract");
 
-    DiagnosticFactory<PsiElement> PACKAGE_MEMBER_CANNOT_BE_PROTECTED = DiagnosticFactory.create(ERROR, "Package member cannot be protected");
+    SimpleDiagnosticFactory<PsiElement>
+            PACKAGE_MEMBER_CANNOT_BE_PROTECTED = SimpleDiagnosticFactory.create(ERROR, "Package member cannot be protected");
 
-    DiagnosticFactory<PsiElement> GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY = DiagnosticFactory.create(ERROR, "Getter visibility must be the same as property visibility");
-    DiagnosticFactory<JetProperty> BACKING_FIELD_IN_TRAIT = DiagnosticFactory.create(ERROR, "Property in a trait cannot have a backing field", PositioningStrategies.POSITION_NAME_IDENTIFIER);
-    DiagnosticFactory<JetProperty> MUST_BE_INITIALIZED = DiagnosticFactory.create(ERROR, "Property must be initialized", PositioningStrategies.POSITION_NAME_IDENTIFIER);
-    DiagnosticFactory<JetProperty> MUST_BE_INITIALIZED_OR_BE_ABSTRACT = DiagnosticFactory.create(ERROR, "Property must be initialized or be abstract", PositioningStrategies.POSITION_NAME_IDENTIFIER);
-    DiagnosticFactory<JetExpression> PROPERTY_INITIALIZER_IN_TRAIT = DiagnosticFactory.create(ERROR, "Property initializers are not allowed in traits");
-    DiagnosticFactory<JetExpression> PROPERTY_INITIALIZER_NO_BACKING_FIELD = DiagnosticFactory.create(ERROR, "Initializer is not allowed here because this property has no backing field");
+    SimpleDiagnosticFactory<PsiElement> GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY = SimpleDiagnosticFactory
+            .create(ERROR, "Getter visibility must be the same as property visibility");
+    SimpleDiagnosticFactory<JetProperty> BACKING_FIELD_IN_TRAIT = SimpleDiagnosticFactory
+            .create(ERROR, "Property in a trait cannot have a backing field", PositioningStrategies.POSITION_NAME_IDENTIFIER);
+    SimpleDiagnosticFactory<JetProperty> MUST_BE_INITIALIZED = SimpleDiagnosticFactory
+            .create(ERROR, "Property must be initialized", PositioningStrategies.POSITION_NAME_IDENTIFIER);
+    SimpleDiagnosticFactory<JetProperty> MUST_BE_INITIALIZED_OR_BE_ABSTRACT = SimpleDiagnosticFactory
+            .create(ERROR, "Property must be initialized or be abstract", PositioningStrategies.POSITION_NAME_IDENTIFIER);
+    SimpleDiagnosticFactory<JetExpression>
+            PROPERTY_INITIALIZER_IN_TRAIT = SimpleDiagnosticFactory.create(ERROR, "Property initializers are not allowed in traits");
+    SimpleDiagnosticFactory<JetExpression> PROPERTY_INITIALIZER_NO_BACKING_FIELD = SimpleDiagnosticFactory
+            .create(ERROR, "Initializer is not allowed here because this property has no backing field");
     DiagnosticFactory3<JetModifierListOwner, String, ClassDescriptor, JetClass> ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS = DiagnosticFactory3.create(ERROR, "Abstract property {0} in non-abstract class {1}", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
     DiagnosticFactory3<JetFunction, String, ClassDescriptor, JetClass> ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS = DiagnosticFactory3.create(ERROR, "Abstract function {0} in non-abstract class {1}", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
     DiagnosticFactory1<JetFunction, SimpleFunctionDescriptor> ABSTRACT_FUNCTION_WITH_BODY = DiagnosticFactory1.create(ERROR, "A function {0} with body cannot be abstract", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
@@ -144,18 +177,28 @@ public interface Errors {
     DiagnosticFactory1<JetModifierListOwner, SimpleFunctionDescriptor> NON_MEMBER_ABSTRACT_FUNCTION = DiagnosticFactory1.create(ERROR, "Function {0} is not a class or trait member and cannot be abstract", PositioningStrategies.POSITION_ABSTRACT_MODIFIER);
 
     DiagnosticFactory1<JetFunction, SimpleFunctionDescriptor> NON_MEMBER_FUNCTION_NO_BODY = DiagnosticFactory1.create(ERROR, "Function {0} must have a body", PositioningStrategies.POSITION_NAME_IDENTIFIER);
-    DiagnosticFactory<JetNamedDeclaration> NON_FINAL_MEMBER_IN_FINAL_CLASS = DiagnosticFactory.create(ERROR, "Non final member in a final class", PositioningStrategies.positionModifier(JetTokens.OPEN_KEYWORD));
+    SimpleDiagnosticFactory<JetNamedDeclaration> NON_FINAL_MEMBER_IN_FINAL_CLASS = SimpleDiagnosticFactory
+            .create(ERROR, "Non final member in a final class", PositioningStrategies.positionModifier(JetTokens.OPEN_KEYWORD));
 
-    DiagnosticFactory<JetNamedDeclaration> PUBLIC_MEMBER_SHOULD_SPECIFY_TYPE = DiagnosticFactory.create(ERROR, "Public or protected member should specify a type", PositioningStrategies.POSITION_NAME_IDENTIFIER);
+    SimpleDiagnosticFactory<JetNamedDeclaration> PUBLIC_MEMBER_SHOULD_SPECIFY_TYPE = SimpleDiagnosticFactory
+            .create(ERROR, "Public or protected member should specify a type", PositioningStrategies.POSITION_NAME_IDENTIFIER);
 
-    DiagnosticFactory<JetTypeProjection> PROJECTION_ON_NON_CLASS_TYPE_ARGUMENT = DiagnosticFactory.create(ERROR, "Projections are not allowed on type arguments of functions and properties"); // TODO : better positioning
-    DiagnosticFactory<JetDelegatorToSuperClass> SUPERTYPE_NOT_INITIALIZED = DiagnosticFactory.create(ERROR, "This type has a constructor, and thus must be initialized here");
-    DiagnosticFactory<JetDelegatorToSuperClass> SUPERTYPE_NOT_INITIALIZED_DEFAULT = DiagnosticFactory.create(ERROR, "Constructor invocation should be explicitly specified");
-    DiagnosticFactory<PsiElement> SECONDARY_CONSTRUCTOR_BUT_NO_PRIMARY = DiagnosticFactory.create(ERROR, "A secondary constructor may appear only in a class that has a primary constructor");
-    DiagnosticFactory<PsiElement> SECONDARY_CONSTRUCTOR_NO_INITIALIZER_LIST = DiagnosticFactory.create(ERROR, "Secondary constructors must have an initializer list");
-    DiagnosticFactory<JetDelegatorByExpressionSpecifier> BY_IN_SECONDARY_CONSTRUCTOR = DiagnosticFactory.create(ERROR, "'by'-clause is only supported for primary constructors");
-    DiagnosticFactory<JetDelegatorToSuperClass> INITIALIZER_WITH_NO_ARGUMENTS = DiagnosticFactory.create(ERROR, "Constructor arguments required");
-    DiagnosticFactory<JetDelegationSpecifier> MANY_CALLS_TO_THIS = DiagnosticFactory.create(ERROR, "Only one call to 'this(...)' is allowed");
+    SimpleDiagnosticFactory<JetTypeProjection> PROJECTION_ON_NON_CLASS_TYPE_ARGUMENT = SimpleDiagnosticFactory
+            .create(ERROR, "Projections are not allowed on type arguments of functions and properties"); // TODO : better positioning
+    SimpleDiagnosticFactory<JetDelegatorToSuperClass> SUPERTYPE_NOT_INITIALIZED = SimpleDiagnosticFactory
+            .create(ERROR, "This type has a constructor, and thus must be initialized here");
+    SimpleDiagnosticFactory<JetDelegatorToSuperClass> SUPERTYPE_NOT_INITIALIZED_DEFAULT = SimpleDiagnosticFactory
+            .create(ERROR, "Constructor invocation should be explicitly specified");
+    SimpleDiagnosticFactory<PsiElement> SECONDARY_CONSTRUCTOR_BUT_NO_PRIMARY = SimpleDiagnosticFactory
+            .create(ERROR, "A secondary constructor may appear only in a class that has a primary constructor");
+    SimpleDiagnosticFactory<PsiElement> SECONDARY_CONSTRUCTOR_NO_INITIALIZER_LIST = SimpleDiagnosticFactory
+            .create(ERROR, "Secondary constructors must have an initializer list");
+    SimpleDiagnosticFactory<JetDelegatorByExpressionSpecifier>
+            BY_IN_SECONDARY_CONSTRUCTOR = SimpleDiagnosticFactory.create(ERROR, "'by'-clause is only supported for primary constructors");
+    SimpleDiagnosticFactory<JetDelegatorToSuperClass>
+            INITIALIZER_WITH_NO_ARGUMENTS = SimpleDiagnosticFactory.create(ERROR, "Constructor arguments required");
+    SimpleDiagnosticFactory<JetDelegationSpecifier>
+            MANY_CALLS_TO_THIS = SimpleDiagnosticFactory.create(ERROR, "Only one call to 'this(...)' is allowed");
     DiagnosticFactory1<JetModifierListOwner, CallableMemberDescriptor> NOTHING_TO_OVERRIDE = DiagnosticFactory1.create(ERROR, "{0} overrides nothing", PositioningStrategies.positionModifier(JetTokens.OVERRIDE_KEYWORD), DescriptorRenderer.TEXT);
     DiagnosticFactory3<PsiNameIdentifierOwner, CallableMemberDescriptor, CallableMemberDescriptor, DeclarationDescriptor> VIRTUAL_MEMBER_HIDDEN = DiagnosticFactory3.create(ERROR, "''{0}'' hides ''{1}'' in class {2} and needs 'override' modifier", PositioningStrategies.POSITION_NAME_IDENTIFIER, DescriptorRenderer.TEXT, DescriptorRenderer.TEXT, DescriptorRenderer.TEXT);
 
@@ -170,88 +213,123 @@ public interface Errors {
     DiagnosticFactory1<JetExpression, DeclarationDescriptor> VARIABLE_WITH_REDUNDANT_INITIALIZER = DiagnosticFactory1.create(WARNING, "Variable ''{0}'' initializer is redundant", NAME);
     DiagnosticFactory2<JetElement, JetElement, DeclarationDescriptor> UNUSED_VALUE = DiagnosticFactory2.create(WARNING, "The value ''{0}'' assigned to ''{1}'' is never used", ELEMENT_TEXT, TO_STRING);
     DiagnosticFactory1<JetElement, JetElement> UNUSED_CHANGED_VALUE = DiagnosticFactory1.create(WARNING, "The value changed at ''{0}'' is never used", ELEMENT_TEXT);
-    DiagnosticFactory<JetElement> UNUSED_EXPRESSION = DiagnosticFactory.create(WARNING, "The expression is unused");
-    DiagnosticFactory<JetFunctionLiteralExpression> UNUSED_FUNCTION_LITERAL = DiagnosticFactory.create(WARNING, "The function literal is unused. If you mean block, you can use 'run { ... }'");
+    SimpleDiagnosticFactory<JetElement> UNUSED_EXPRESSION = SimpleDiagnosticFactory.create(WARNING, "The expression is unused");
+    SimpleDiagnosticFactory<JetFunctionLiteralExpression> UNUSED_FUNCTION_LITERAL = SimpleDiagnosticFactory
+            .create(WARNING, "The function literal is unused. If you mean block, you can use 'run { ... }'");
 
     DiagnosticFactory1<JetExpression, DeclarationDescriptor> VAL_REASSIGNMENT = DiagnosticFactory1.create(ERROR, "Val can not be reassigned", NAME);
     DiagnosticFactory1<JetExpression, DeclarationDescriptor> INITIALIZATION_BEFORE_DECLARATION = DiagnosticFactory1.create(ERROR, "Variable cannot be initialized before declaration", NAME);
-    DiagnosticFactory<JetExpression> VARIABLE_EXPECTED = DiagnosticFactory.create(ERROR, "Variable expected");
+    SimpleDiagnosticFactory<JetExpression> VARIABLE_EXPECTED = SimpleDiagnosticFactory.create(ERROR, "Variable expected");
 
     DiagnosticFactory1<JetExpression, DeclarationDescriptor> INITIALIZATION_USING_BACKING_FIELD_CUSTOM_SETTER = DiagnosticFactory1.create(ERROR, "This property has a custom setter, so initialization using backing field required", NAME);
     DiagnosticFactory1<JetExpression, DeclarationDescriptor> INITIALIZATION_USING_BACKING_FIELD_OPEN_SETTER = DiagnosticFactory1.create(ERROR, "Setter of this property can be overridden, so initialization using backing field required", NAME);
 
     DiagnosticFactory1<JetSimpleNameExpression, DeclarationDescriptor> FUNCTION_PARAMETERS_OF_INLINE_FUNCTION = DiagnosticFactory1.create(ERROR, "Function parameters of inline function can only be invoked", NAME);
 
-    DiagnosticFactory<JetElement> UNREACHABLE_CODE = DiagnosticFactory.create(ERROR, "Unreachable code");
+    SimpleDiagnosticFactory<JetElement> UNREACHABLE_CODE = SimpleDiagnosticFactory.create(ERROR, "Unreachable code");
 
-    DiagnosticFactory<JetClassObject> MANY_CLASS_OBJECTS = DiagnosticFactory.create(ERROR, "Only one class object is allowed per class");
-    DiagnosticFactory<JetClassObject> CLASS_OBJECT_NOT_ALLOWED = DiagnosticFactory.create(ERROR, "A class object is not allowed here");
-    DiagnosticFactory<JetDelegatorByExpressionSpecifier> DELEGATION_IN_TRAIT = DiagnosticFactory.create(ERROR, "Traits cannot use delegation");
-    DiagnosticFactory<JetTypeReference> DELEGATION_NOT_TO_TRAIT = DiagnosticFactory.create(ERROR, "Only traits can be delegated to");
-    DiagnosticFactory<PsiElement> NO_CONSTRUCTOR = DiagnosticFactory.create(ERROR, "This class does not have a constructor");
-    DiagnosticFactory<JetExpression> NOT_A_CLASS = DiagnosticFactory.create(ERROR, "Not a class");
-    DiagnosticFactory<JetEscapeStringTemplateEntry> ILLEGAL_ESCAPE_SEQUENCE = DiagnosticFactory.create(ERROR, "Illegal escape sequence");
+    SimpleDiagnosticFactory<JetClassObject>
+            MANY_CLASS_OBJECTS = SimpleDiagnosticFactory.create(ERROR, "Only one class object is allowed per class");
+    SimpleDiagnosticFactory<JetClassObject>
+            CLASS_OBJECT_NOT_ALLOWED = SimpleDiagnosticFactory.create(ERROR, "A class object is not allowed here");
+    SimpleDiagnosticFactory<JetDelegatorByExpressionSpecifier>
+            DELEGATION_IN_TRAIT = SimpleDiagnosticFactory.create(ERROR, "Traits cannot use delegation");
+    SimpleDiagnosticFactory<JetTypeReference>
+            DELEGATION_NOT_TO_TRAIT = SimpleDiagnosticFactory.create(ERROR, "Only traits can be delegated to");
+    SimpleDiagnosticFactory<PsiElement> NO_CONSTRUCTOR = SimpleDiagnosticFactory.create(ERROR, "This class does not have a constructor");
+    SimpleDiagnosticFactory<JetExpression> NOT_A_CLASS = SimpleDiagnosticFactory.create(ERROR, "Not a class");
+    SimpleDiagnosticFactory<JetEscapeStringTemplateEntry>
+            ILLEGAL_ESCAPE_SEQUENCE = SimpleDiagnosticFactory.create(ERROR, "Illegal escape sequence");
 
-    DiagnosticFactory<JetTypeReference> LOCAL_EXTENSION_PROPERTY = DiagnosticFactory.create(ERROR, "Local extension properties are not allowed");
-    DiagnosticFactory<JetPropertyAccessor> LOCAL_VARIABLE_WITH_GETTER = DiagnosticFactory.create(ERROR, "Local variables are not allowed to have getters");
-    DiagnosticFactory<JetPropertyAccessor> LOCAL_VARIABLE_WITH_SETTER = DiagnosticFactory.create(ERROR, "Local variables are not allowed to have setters");
-    DiagnosticFactory<JetPropertyAccessor> VAL_WITH_SETTER = DiagnosticFactory.create(ERROR, "A 'val'-property cannot have a setter");
+    SimpleDiagnosticFactory<JetTypeReference>
+            LOCAL_EXTENSION_PROPERTY = SimpleDiagnosticFactory.create(ERROR, "Local extension properties are not allowed");
+    SimpleDiagnosticFactory<JetPropertyAccessor>
+            LOCAL_VARIABLE_WITH_GETTER = SimpleDiagnosticFactory.create(ERROR, "Local variables are not allowed to have getters");
+    SimpleDiagnosticFactory<JetPropertyAccessor>
+            LOCAL_VARIABLE_WITH_SETTER = SimpleDiagnosticFactory.create(ERROR, "Local variables are not allowed to have setters");
+    SimpleDiagnosticFactory<JetPropertyAccessor>
+            VAL_WITH_SETTER = SimpleDiagnosticFactory.create(ERROR, "A 'val'-property cannot have a setter");
 
-    DiagnosticFactory<JetArrayAccessExpression> NO_GET_METHOD = DiagnosticFactory.create(ERROR, "No get method providing array access", PositioningStrategies.POSITION_ARRAY_ACCESS);
-    DiagnosticFactory<JetArrayAccessExpression> NO_SET_METHOD = DiagnosticFactory.create(ERROR, "No set method providing array access", PositioningStrategies.POSITION_ARRAY_ACCESS);
+    SimpleDiagnosticFactory<JetArrayAccessExpression> NO_GET_METHOD = SimpleDiagnosticFactory
+            .create(ERROR, "No get method providing array access", PositioningStrategies.POSITION_ARRAY_ACCESS);
+    SimpleDiagnosticFactory<JetArrayAccessExpression> NO_SET_METHOD = SimpleDiagnosticFactory
+            .create(ERROR, "No set method providing array access", PositioningStrategies.POSITION_ARRAY_ACCESS);
 
-    DiagnosticFactory<JetSimpleNameExpression> INC_DEC_SHOULD_NOT_RETURN_UNIT = DiagnosticFactory.create(ERROR, "Functions inc(), dec() shouldn't return Unit to be used by operators ++, --");
+    SimpleDiagnosticFactory<JetSimpleNameExpression> INC_DEC_SHOULD_NOT_RETURN_UNIT = SimpleDiagnosticFactory
+            .create(ERROR, "Functions inc(), dec() shouldn't return Unit to be used by operators ++, --");
     DiagnosticFactory2<JetSimpleNameExpression, DeclarationDescriptor, JetSimpleNameExpression> ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT =
             DiagnosticFactory2.create(ERROR, "Function ''{0}'' should return Unit to be used by corresponding operator ''{1}''", NAME, ELEMENT_TEXT);
     AmbiguousDescriptorDiagnosticFactory ASSIGN_OPERATOR_AMBIGUITY = AmbiguousDescriptorDiagnosticFactory.create("Assignment operators ambiguity: {0}");
 
-    DiagnosticFactory<JetSimpleNameExpression> EQUALS_MISSING = DiagnosticFactory.create(ERROR, "No method 'equals(Any?) : Boolean' available");
-    DiagnosticFactory<JetBinaryExpression> ASSIGNMENT_IN_EXPRESSION_CONTEXT = DiagnosticFactory.create(ERROR, "Assignments are not expressions, and only expressions are allowed in this context");
-    DiagnosticFactory<JetRootNamespaceExpression> NAMESPACE_IS_NOT_AN_EXPRESSION = DiagnosticFactory.create(ERROR, "'namespace' is not an expression, it can only be used on the left-hand side of a dot ('.')");
+    SimpleDiagnosticFactory<JetSimpleNameExpression>
+            EQUALS_MISSING = SimpleDiagnosticFactory.create(ERROR, "No method 'equals(Any?) : Boolean' available");
+    SimpleDiagnosticFactory<JetBinaryExpression> ASSIGNMENT_IN_EXPRESSION_CONTEXT = SimpleDiagnosticFactory
+            .create(ERROR, "Assignments are not expressions, and only expressions are allowed in this context");
+    SimpleDiagnosticFactory<JetRootNamespaceExpression> NAMESPACE_IS_NOT_AN_EXPRESSION = SimpleDiagnosticFactory
+            .create(ERROR, "'namespace' is not an expression, it can only be used on the left-hand side of a dot ('.')");
     DiagnosticFactory1<JetSuperExpression, String> SUPER_IS_NOT_AN_EXPRESSION = DiagnosticFactory1.create(ERROR, "{0} is not an expression, it can only be used on the left-hand side of a dot ('.')");
-    DiagnosticFactory<JetDeclaration> DECLARATION_IN_ILLEGAL_CONTEXT = DiagnosticFactory.create(ERROR, "Declarations are not allowed in this position");
-    DiagnosticFactory<JetExpression> SETTER_PARAMETER_WITH_DEFAULT_VALUE = DiagnosticFactory.create(ERROR, "Setter parameters can not have default values");
-    DiagnosticFactory<JetThisExpression> NO_THIS = DiagnosticFactory.create(ERROR, "'this' is not defined in this context");
-    DiagnosticFactory<JetSuperExpression> SUPER_NOT_AVAILABLE = DiagnosticFactory.create(ERROR, "No supertypes are accessible in this context");
-    DiagnosticFactory<JetSuperExpression> AMBIGUOUS_SUPER = DiagnosticFactory.create(ERROR, "Many supertypes available, please specify the one you mean in angle brackets, e.g. 'super<Foo>'");
-    DiagnosticFactory<JetExpression> ABSTRACT_SUPER_CALL = DiagnosticFactory.create(ERROR, "Abstract member cannot be accessed directly");
-    DiagnosticFactory<JetTypeReference> NOT_A_SUPERTYPE = DiagnosticFactory.create(ERROR, "Not a supertype");
-    DiagnosticFactory<PsiElement> TYPE_ARGUMENTS_REDUNDANT_IN_SUPER_QUALIFIER = DiagnosticFactory.create(WARNING, "Type arguments do not need to be specified in a 'super' qualifier");
-    DiagnosticFactory<JetSimpleNameExpression> USELESS_CAST_STATIC_ASSERT_IS_FINE = DiagnosticFactory.create(WARNING, "No cast needed, use ':' instead");
-    DiagnosticFactory<JetSimpleNameExpression> USELESS_CAST = DiagnosticFactory.create(WARNING, "No cast needed");
-    DiagnosticFactory<JetSimpleNameExpression> CAST_NEVER_SUCCEEDS = DiagnosticFactory.create(WARNING, "This cast can never succeed");
+    SimpleDiagnosticFactory<JetDeclaration>
+            DECLARATION_IN_ILLEGAL_CONTEXT = SimpleDiagnosticFactory.create(ERROR, "Declarations are not allowed in this position");
+    SimpleDiagnosticFactory<JetExpression>
+            SETTER_PARAMETER_WITH_DEFAULT_VALUE = SimpleDiagnosticFactory.create(ERROR, "Setter parameters can not have default values");
+    SimpleDiagnosticFactory<JetThisExpression> NO_THIS = SimpleDiagnosticFactory.create(ERROR, "'this' is not defined in this context");
+    SimpleDiagnosticFactory<JetSuperExpression>
+            SUPER_NOT_AVAILABLE = SimpleDiagnosticFactory.create(ERROR, "No supertypes are accessible in this context");
+    SimpleDiagnosticFactory<JetSuperExpression> AMBIGUOUS_SUPER = SimpleDiagnosticFactory
+            .create(ERROR, "Many supertypes available, please specify the one you mean in angle brackets, e.g. 'super<Foo>'");
+    SimpleDiagnosticFactory<JetExpression>
+            ABSTRACT_SUPER_CALL = SimpleDiagnosticFactory.create(ERROR, "Abstract member cannot be accessed directly");
+    SimpleDiagnosticFactory<JetTypeReference> NOT_A_SUPERTYPE = SimpleDiagnosticFactory.create(ERROR, "Not a supertype");
+    SimpleDiagnosticFactory<PsiElement> TYPE_ARGUMENTS_REDUNDANT_IN_SUPER_QUALIFIER = SimpleDiagnosticFactory
+            .create(WARNING, "Type arguments do not need to be specified in a 'super' qualifier");
+    SimpleDiagnosticFactory<JetSimpleNameExpression>
+            USELESS_CAST_STATIC_ASSERT_IS_FINE = SimpleDiagnosticFactory.create(WARNING, "No cast needed, use ':' instead");
+    SimpleDiagnosticFactory<JetSimpleNameExpression> USELESS_CAST = SimpleDiagnosticFactory.create(WARNING, "No cast needed");
+    SimpleDiagnosticFactory<JetSimpleNameExpression>
+            CAST_NEVER_SUCCEEDS = SimpleDiagnosticFactory.create(WARNING, "This cast can never succeed");
     DiagnosticFactory1<JetTypeReference, JetType> WRONG_SETTER_PARAMETER_TYPE = DiagnosticFactory1.create(ERROR, "Setter parameter type must be equal to the type of the property, i.e. {0}", RENDER_TYPE);//, DiagnosticParameters.TYPE);
     DiagnosticFactory1<JetTypeReference, JetType> WRONG_GETTER_RETURN_TYPE = DiagnosticFactory1.create(ERROR, "Getter return type must be equal to the type of the property, i.e. {0}", RENDER_TYPE);//, DiagnosticParameters.TYPE);
     DiagnosticFactory1<JetSimpleNameExpression, ClassifierDescriptor> NO_CLASS_OBJECT = DiagnosticFactory1.create(ERROR, "Please specify constructor invocation; classifier {0} does not have a class object", NAME);
-    DiagnosticFactory<PsiElement> NO_GENERICS_IN_SUPERTYPE_SPECIFIER = DiagnosticFactory.create(ERROR, "Generic arguments of the base type must be specified");
+    SimpleDiagnosticFactory<PsiElement> NO_GENERICS_IN_SUPERTYPE_SPECIFIER = SimpleDiagnosticFactory
+            .create(ERROR, "Generic arguments of the base type must be specified");
 
-    DiagnosticFactory<JetExpression> HAS_NEXT_PROPERTY_AND_FUNCTION_AMBIGUITY = DiagnosticFactory.create(ERROR, "An ambiguity between 'iterator().hasNext()' function and 'iterator().hasNext' property");
-    DiagnosticFactory<JetExpression> HAS_NEXT_MISSING = DiagnosticFactory.create(ERROR, "Loop range must have an 'iterator().hasNext()' function or an 'iterator().hasNext' property");
-    DiagnosticFactory<JetExpression> HAS_NEXT_FUNCTION_AMBIGUITY = DiagnosticFactory.create(ERROR, "Function 'iterator().hasNext()' is ambiguous for this expression");
-    DiagnosticFactory<JetExpression> HAS_NEXT_MUST_BE_READABLE = DiagnosticFactory.create(ERROR, "The 'iterator().hasNext' property of the loop range must be readable");
+    SimpleDiagnosticFactory<JetExpression> HAS_NEXT_PROPERTY_AND_FUNCTION_AMBIGUITY = SimpleDiagnosticFactory
+            .create(ERROR, "An ambiguity between 'iterator().hasNext()' function and 'iterator().hasNext' property");
+    SimpleDiagnosticFactory<JetExpression> HAS_NEXT_MISSING = SimpleDiagnosticFactory
+            .create(ERROR, "Loop range must have an 'iterator().hasNext()' function or an 'iterator().hasNext' property");
+    SimpleDiagnosticFactory<JetExpression> HAS_NEXT_FUNCTION_AMBIGUITY = SimpleDiagnosticFactory
+            .create(ERROR, "Function 'iterator().hasNext()' is ambiguous for this expression");
+    SimpleDiagnosticFactory<JetExpression> HAS_NEXT_MUST_BE_READABLE = SimpleDiagnosticFactory
+            .create(ERROR, "The 'iterator().hasNext' property of the loop range must be readable");
     DiagnosticFactory1<JetExpression, JetType> HAS_NEXT_PROPERTY_TYPE_MISMATCH = DiagnosticFactory1.create(ERROR, "The 'iterator().hasNext' property of the loop range must return Boolean, but returns {0}", RENDER_TYPE);
     DiagnosticFactory1<JetExpression, JetType> HAS_NEXT_FUNCTION_TYPE_MISMATCH = DiagnosticFactory1.create(ERROR, "The 'iterator().hasNext()' function of the loop range must return Boolean, but returns {0}", RENDER_TYPE);
-    DiagnosticFactory<JetExpression> NEXT_AMBIGUITY = DiagnosticFactory.create(ERROR, "Function 'iterator().next()' is ambiguous for this expression");
-    DiagnosticFactory<JetExpression> NEXT_MISSING = DiagnosticFactory.create(ERROR, "Loop range must have an 'iterator().next()' function");
-    DiagnosticFactory<JetExpression> ITERATOR_MISSING = DiagnosticFactory.create(ERROR, "For-loop range must have an iterator() method");
+    SimpleDiagnosticFactory<JetExpression>
+            NEXT_AMBIGUITY = SimpleDiagnosticFactory.create(ERROR, "Function 'iterator().next()' is ambiguous for this expression");
+    SimpleDiagnosticFactory<JetExpression>
+            NEXT_MISSING = SimpleDiagnosticFactory.create(ERROR, "Loop range must have an 'iterator().next()' function");
+    SimpleDiagnosticFactory<JetExpression>
+            ITERATOR_MISSING = SimpleDiagnosticFactory.create(ERROR, "For-loop range must have an iterator() method");
     AmbiguousDescriptorDiagnosticFactory ITERATOR_AMBIGUITY = AmbiguousDescriptorDiagnosticFactory.create("Method 'iterator()' is ambiguous for this expression: {0}");
 
     DiagnosticFactory1<JetSimpleNameExpression, JetType> COMPARE_TO_TYPE_MISMATCH = DiagnosticFactory1.create(ERROR, "compareTo() must return Int, but returns {0}", RENDER_TYPE);
     DiagnosticFactory1<JetExpression, JetType> CALLEE_NOT_A_FUNCTION = DiagnosticFactory1.create(ERROR, "Expecting a function type, but found {0}", RENDER_TYPE);
 
-    DiagnosticFactory<JetReturnExpression> RETURN_IN_FUNCTION_WITH_EXPRESSION_BODY = DiagnosticFactory.create(ERROR, "Returns are not allowed for functions with expression body. Use block body in '{...}'");
-    DiagnosticFactory<JetDeclarationWithBody> NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY = DiagnosticFactory.create(ERROR, "A 'return' expression required in a function with a block body ('{...}')", new PositioningStrategy<JetDeclarationWithBody>() {
-        @NotNull
-        @Override
-        public List<TextRange> mark(@NotNull JetDeclarationWithBody element) {
-            JetExpression bodyExpression = element.getBodyExpression();
-            if (!(bodyExpression instanceof JetBlockExpression)) return Collections.emptyList();
-            JetBlockExpression blockExpression = (JetBlockExpression) bodyExpression;
-            TextRange lastBracketRange = blockExpression.getLastBracketRange();
-            if (lastBracketRange == null) return Collections.emptyList();
-            return markRange(lastBracketRange);
-        }
-    });
+    SimpleDiagnosticFactory<JetReturnExpression> RETURN_IN_FUNCTION_WITH_EXPRESSION_BODY = SimpleDiagnosticFactory
+            .create(ERROR, "Returns are not allowed for functions with expression body. Use block body in '{...}'");
+    SimpleDiagnosticFactory<JetDeclarationWithBody> NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY = SimpleDiagnosticFactory
+            .create(ERROR, "A 'return' expression required in a function with a block body ('{...}')",
+                    new PositioningStrategy<JetDeclarationWithBody>() {
+                        @NotNull
+                        @Override
+                        public List<TextRange> mark(@NotNull JetDeclarationWithBody element) {
+                            JetExpression bodyExpression = element.getBodyExpression();
+                            if (!(bodyExpression instanceof JetBlockExpression)) return Collections.emptyList();
+                            JetBlockExpression blockExpression = (JetBlockExpression)bodyExpression;
+                            TextRange lastBracketRange = blockExpression.getLastBracketRange();
+                            if (lastBracketRange == null) return Collections.emptyList();
+                            return markRange(lastBracketRange);
+                        }
+                    });
     DiagnosticFactory1<JetExpression, JetType> RETURN_TYPE_MISMATCH = DiagnosticFactory1.create(ERROR, "This function must return a value of type {0}", RENDER_TYPE);
     DiagnosticFactory1<JetExpression, JetType> EXPECTED_TYPE_MISMATCH = DiagnosticFactory1.create(ERROR, "Expected a value of type {0}", RENDER_TYPE);
     DiagnosticFactory1<JetBinaryExpression, JetType> ASSIGNMENT_TYPE_MISMATCH = DiagnosticFactory1.create(ERROR, "Expected a value of type {0}. Assignment operation is not an expression, so it does not return any value", RENDER_TYPE);
@@ -276,7 +354,7 @@ public interface Errors {
     DiagnosticFactory1<PsiElement, CallableDescriptor> TOO_MANY_ARGUMENTS = DiagnosticFactory1.create(ERROR, "Too many arguments for {0}");
     DiagnosticFactory1<PsiElement, String> ERROR_COMPILE_TIME_VALUE = DiagnosticFactory1.create(ERROR, "{0}");
 
-    DiagnosticFactory<JetWhenEntry> ELSE_MISPLACED_IN_WHEN = DiagnosticFactory.create(
+    SimpleDiagnosticFactory<JetWhenEntry> ELSE_MISPLACED_IN_WHEN = SimpleDiagnosticFactory.create(
             ERROR, "'else' entry must be the last one in a when-expression", new PositioningStrategy<JetWhenEntry>() {
         @NotNull
         @Override
@@ -287,7 +365,8 @@ public interface Errors {
         }
     });
 
-    DiagnosticFactory<JetWhenExpression> NO_ELSE_IN_WHEN = new DiagnosticFactory<JetWhenExpression>(ERROR, "'when' expression must contain 'else' branch", new PositioningStrategy<JetWhenExpression>() {
+    SimpleDiagnosticFactory<JetWhenExpression>
+            NO_ELSE_IN_WHEN = new SimpleDiagnosticFactory<JetWhenExpression>(ERROR, "'when' expression must contain 'else' branch", new PositioningStrategy<JetWhenExpression>() {
         @NotNull
         @Override
         public List<TextRange> mark(@NotNull JetWhenExpression element) {
@@ -295,40 +374,50 @@ public interface Errors {
             return markElement(element.getWhenKeywordElement());
         }
     });
-    DiagnosticFactory<JetWhenConditionInRange> TYPE_MISMATCH_IN_RANGE = new DiagnosticFactory<JetWhenConditionInRange>(ERROR, "Type mismatch: incompatible types of range and element checked in it", new PositioningStrategy<JetWhenConditionInRange>() {
+    SimpleDiagnosticFactory<JetWhenConditionInRange> TYPE_MISMATCH_IN_RANGE = new SimpleDiagnosticFactory<JetWhenConditionInRange>(ERROR, "Type mismatch: incompatible types of range and element checked in it", new PositioningStrategy<JetWhenConditionInRange>() {
         @NotNull
         @Override
         public List<TextRange> mark(@NotNull JetWhenConditionInRange condition) {
             return markElement(condition.getOperationReference());
         }
     });
-    DiagnosticFactory<PsiElement> CYCLIC_INHERITANCE_HIERARCHY = DiagnosticFactory.create(ERROR, "There's a cycle in the inheritance hierarchy for this type");
+    SimpleDiagnosticFactory<PsiElement> CYCLIC_INHERITANCE_HIERARCHY = SimpleDiagnosticFactory
+            .create(ERROR, "There's a cycle in the inheritance hierarchy for this type");
 
-    DiagnosticFactory<JetTypeReference> MANY_CLASSES_IN_SUPERTYPE_LIST = DiagnosticFactory.create(ERROR, "Only one class may appear in a supertype list");
-    DiagnosticFactory<JetTypeReference> SUPERTYPE_NOT_A_CLASS_OR_TRAIT = DiagnosticFactory.create(ERROR, "Only classes and traits may serve as supertypes");
-    DiagnosticFactory<PsiElement> SUPERTYPE_INITIALIZED_IN_TRAIT = DiagnosticFactory.create(ERROR, "Traits cannot initialize supertypes");
-    DiagnosticFactory<PsiElement> CONSTRUCTOR_IN_TRAIT = DiagnosticFactory.create(ERROR, "A trait may not have a constructor");
-    DiagnosticFactory<JetSecondaryConstructor> SECONDARY_CONSTRUCTORS_ARE_NOT_SUPPORTED = DiagnosticFactory.create(WARNING, "Secondary constructors are not supported");
-    DiagnosticFactory<JetTypeReference> SUPERTYPE_APPEARS_TWICE = DiagnosticFactory.create(ERROR, "A supertype appears twice");
-    DiagnosticFactory<JetTypeReference> FINAL_SUPERTYPE = DiagnosticFactory.create(ERROR, "This type is final, so it cannot be inherited from");
+    SimpleDiagnosticFactory<JetTypeReference>
+            MANY_CLASSES_IN_SUPERTYPE_LIST = SimpleDiagnosticFactory.create(ERROR, "Only one class may appear in a supertype list");
+    SimpleDiagnosticFactory<JetTypeReference>
+            SUPERTYPE_NOT_A_CLASS_OR_TRAIT = SimpleDiagnosticFactory.create(ERROR, "Only classes and traits may serve as supertypes");
+    SimpleDiagnosticFactory<PsiElement>
+            SUPERTYPE_INITIALIZED_IN_TRAIT = SimpleDiagnosticFactory.create(ERROR, "Traits cannot initialize supertypes");
+    SimpleDiagnosticFactory<PsiElement> CONSTRUCTOR_IN_TRAIT = SimpleDiagnosticFactory.create(ERROR, "A trait may not have a constructor");
+    SimpleDiagnosticFactory<JetSecondaryConstructor>
+            SECONDARY_CONSTRUCTORS_ARE_NOT_SUPPORTED = SimpleDiagnosticFactory.create(WARNING, "Secondary constructors are not supported");
+    SimpleDiagnosticFactory<JetTypeReference> SUPERTYPE_APPEARS_TWICE = SimpleDiagnosticFactory.create(ERROR, "A supertype appears twice");
+    SimpleDiagnosticFactory<JetTypeReference>
+            FINAL_SUPERTYPE = SimpleDiagnosticFactory.create(ERROR, "This type is final, so it cannot be inherited from");
 
     DiagnosticFactory1<JetExpression, String> ILLEGAL_SELECTOR = DiagnosticFactory1.create(ERROR, "Expression ''{0}'' cannot be a selector (occur after a dot)");
 
-    DiagnosticFactory<JetParameter> VALUE_PARAMETER_WITH_NO_TYPE_ANNOTATION = DiagnosticFactory.create(ERROR, "A type annotation is required on a value parameter");
-    DiagnosticFactory<JetLabelQualifiedExpression> BREAK_OR_CONTINUE_OUTSIDE_A_LOOP = DiagnosticFactory.create(ERROR, "'break' and 'continue' are only allowed inside a loop");
+    SimpleDiagnosticFactory<JetParameter> VALUE_PARAMETER_WITH_NO_TYPE_ANNOTATION = SimpleDiagnosticFactory
+            .create(ERROR, "A type annotation is required on a value parameter");
+    SimpleDiagnosticFactory<JetLabelQualifiedExpression> BREAK_OR_CONTINUE_OUTSIDE_A_LOOP = SimpleDiagnosticFactory
+            .create(ERROR, "'break' and 'continue' are only allowed inside a loop");
     DiagnosticFactory1<JetLabelQualifiedExpression, String> NOT_A_LOOP_LABEL = DiagnosticFactory1.create(ERROR, "The label ''{0}'' does not denote a loop");
     DiagnosticFactory1<JetReturnExpression, String> NOT_A_RETURN_LABEL = DiagnosticFactory1.create(ERROR, "The label ''{0}'' does not reference to a context from which we can return");
 
-    DiagnosticFactory<JetClassInitializer> ANONYMOUS_INITIALIZER_WITHOUT_CONSTRUCTOR = DiagnosticFactory.create(ERROR, "Anonymous initializers are only allowed in the presence of a primary constructor");
-    DiagnosticFactory<JetNullableType> NULLABLE_SUPERTYPE = DiagnosticFactory.create(ERROR, "A supertype cannot be nullable", new PositioningStrategy<JetNullableType>() {
-        @NotNull
-        @Override
-        public List<TextRange> mark(@NotNull JetNullableType element) {
-            return markNode(element.getQuestionMarkNode());
-        }
-    });
+    SimpleDiagnosticFactory<JetClassInitializer> ANONYMOUS_INITIALIZER_WITHOUT_CONSTRUCTOR = SimpleDiagnosticFactory
+            .create(ERROR, "Anonymous initializers are only allowed in the presence of a primary constructor");
+    SimpleDiagnosticFactory<JetNullableType> NULLABLE_SUPERTYPE = SimpleDiagnosticFactory
+            .create(ERROR, "A supertype cannot be nullable", new PositioningStrategy<JetNullableType>() {
+                @NotNull
+                @Override
+                public List<TextRange> mark(@NotNull JetNullableType element) {
+                    return markNode(element.getQuestionMarkNode());
+                }
+            });
     DiagnosticFactory1<PsiElement, JetType> UNSAFE_CALL = DiagnosticFactory1.create(ERROR, "Only safe calls (?.) are allowed on a nullable receiver of type {0}", RENDER_TYPE);
-    DiagnosticFactory<JetSimpleNameExpression> AMBIGUOUS_LABEL = DiagnosticFactory.create(ERROR, "Ambiguous label");
+    SimpleDiagnosticFactory<JetSimpleNameExpression> AMBIGUOUS_LABEL = SimpleDiagnosticFactory.create(ERROR, "Ambiguous label");
     DiagnosticFactory1<PsiElement, String> UNSUPPORTED = DiagnosticFactory1.create(ERROR, "Unsupported [{0}]");
     DiagnosticFactory1<PsiElement, JetType> UNNECESSARY_SAFE_CALL = DiagnosticFactory1.create(WARNING, "Unnecessary safe call on a non-null receiver of type {0}", RENDER_TYPE);
     DiagnosticFactory1<PsiElement, JetType> UNNECESSARY_NOT_NULL_ASSERTION = DiagnosticFactory1.create(WARNING, "Unnecessary non-null assertion (!!) on a non-null receiver of type {0}", RENDER_TYPE);
@@ -347,7 +436,8 @@ public interface Errors {
     DiagnosticFactory2<JetTuplePattern, JetType, Integer> TYPE_MISMATCH_IN_TUPLE_PATTERN = DiagnosticFactory2.create(ERROR, "Type mismatch: subject is of type {0} but the pattern is of type Tuple{1}", RENDER_TYPE, TO_STRING); // TODO: message
     DiagnosticFactory2<JetTypeReference, JetType, JetType> TYPE_MISMATCH_IN_BINDING_PATTERN = DiagnosticFactory2.create(ERROR, "{0} must be a supertype of {1}. Use 'is' to match against {0}", RENDER_TYPE, RENDER_TYPE);
     DiagnosticFactory2<JetElement, JetType, JetType> INCOMPATIBLE_TYPES = DiagnosticFactory2.create(ERROR, "Incompatible types: {0} and {1}", RENDER_TYPE, RENDER_TYPE);
-    DiagnosticFactory<JetWhenCondition> EXPECTED_CONDITION = DiagnosticFactory.create(ERROR, "Expected condition of Boolean type");
+    SimpleDiagnosticFactory<JetWhenCondition>
+            EXPECTED_CONDITION = SimpleDiagnosticFactory.create(ERROR, "Expected condition of Boolean type");
 
     DiagnosticFactory1<JetElement, JetType> CANNOT_CHECK_FOR_ERASED = DiagnosticFactory1.create(ERROR, "Cannot check for instance of erased type: {0}", RENDER_TYPE);
     DiagnosticFactory2<JetBinaryExpressionWithTypeRHS, JetType, JetType> UNCHECKED_CAST = DiagnosticFactory2.create(WARNING, "Unchecked cast: {0} to {1}", RENDER_TYPE, RENDER_TYPE);
@@ -438,9 +528,11 @@ public interface Errors {
     AmbiguousDescriptorDiagnosticFactory NONE_APPLICABLE = new AmbiguousDescriptorDiagnosticFactory("None of the following functions can be called with the arguments supplied: {0}");
     DiagnosticFactory1<PsiElement, ValueParameterDescriptor> NO_VALUE_FOR_PARAMETER = DiagnosticFactory1.create(ERROR, "No value passed for parameter {0}", DescriptorRenderer.TEXT);
     DiagnosticFactory1<JetReferenceExpression, JetType> MISSING_RECEIVER = DiagnosticFactory1.create(ERROR, "A receiver of type {0} is required", RENDER_TYPE);
-    DiagnosticFactory<JetReferenceExpression> NO_RECEIVER_ADMITTED = DiagnosticFactory.create(ERROR, "No receiver can be passed to this function or property");
+    SimpleDiagnosticFactory<JetReferenceExpression>
+            NO_RECEIVER_ADMITTED = SimpleDiagnosticFactory.create(ERROR, "No receiver can be passed to this function or property");
 
-    DiagnosticFactory<PsiElement> CREATING_AN_INSTANCE_OF_ABSTRACT_CLASS = DiagnosticFactory.create(ERROR, "Can not create an instance of an abstract class");
+    SimpleDiagnosticFactory<PsiElement> CREATING_AN_INSTANCE_OF_ABSTRACT_CLASS = SimpleDiagnosticFactory
+            .create(ERROR, "Can not create an instance of an abstract class");
     DiagnosticFactory1<PsiElement, SolutionStatus> TYPE_INFERENCE_FAILED = DiagnosticFactory1.create(ERROR, "Type inference failed: {0}");
     DiagnosticFactory1<JetElement, Integer> WRONG_NUMBER_OF_TYPE_ARGUMENTS = DiagnosticFactory1.create(ERROR, "{0} type arguments expected", new Renderer<Integer>() {
         @NotNull
@@ -453,8 +545,9 @@ public interface Errors {
 
     DiagnosticFactory1<JetIdeTemplateExpression, String> UNRESOLVED_IDE_TEMPLATE = DiagnosticFactory1.create(ERROR, "Unresolved IDE template: {0}");
 
-    DiagnosticFactory<JetExpression> DANGLING_FUNCTION_LITERAL_ARGUMENT_SUSPECTED = DiagnosticFactory.create(WARNING, "This expression is treated as an argument to the function call on the previous line. " +
-                                                                                                                      "Separate it with a semicolon (;) if it is not intended to be an argument.");
+    SimpleDiagnosticFactory<JetExpression> DANGLING_FUNCTION_LITERAL_ARGUMENT_SUSPECTED = SimpleDiagnosticFactory
+            .create(WARNING, "This expression is treated as an argument to the function call on the previous line. " +
+                             "Separate it with a semicolon (;) if it is not intended to be an argument.");
 
     DiagnosticFactory1<JetAnnotationEntry, String> NOT_AN_ANNOTATION_CLASS = DiagnosticFactory1.create(ERROR, "{0} is not an annotation class");
 
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/DiagnosticWithPsiElement.java b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/SimpleDiagnostic.java
similarity index 79%
rename from compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/DiagnosticWithPsiElement.java
rename to compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/SimpleDiagnostic.java
index 603c0aed730..ddd531f827d 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/DiagnosticWithPsiElement.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/SimpleDiagnostic.java
@@ -25,17 +25,17 @@ import java.util.List;
 /**
  * @author svtk
  */
-public class DiagnosticWithPsiElement<E extends PsiElement> extends AbstractDiagnostic<E> {
-    public DiagnosticWithPsiElement(@NotNull E psiElement,
-            @NotNull DiagnosticFactory<E> factory,
+public class SimpleDiagnostic<E extends PsiElement> extends AbstractDiagnostic<E> {
+    public SimpleDiagnostic(@NotNull E psiElement,
+            @NotNull SimpleDiagnosticFactory<E> factory,
             @NotNull Severity severity) {
         super(psiElement, factory, severity);
     }
 
     @NotNull
     @Override
-    public DiagnosticFactory<E> getFactory() {
-        return (DiagnosticFactory<E>)super.getFactory();
+    public SimpleDiagnosticFactory<E> getFactory() {
+        return (SimpleDiagnosticFactory<E>)super.getFactory();
     }
 
     @NotNull
diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/DiagnosticFactory.java b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/SimpleDiagnosticFactory.java
similarity index 62%
rename from compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/DiagnosticFactory.java
rename to compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/SimpleDiagnosticFactory.java
index b1f03498b4f..4a97b1e460b 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/DiagnosticFactory.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/diagnostics/SimpleDiagnosticFactory.java
@@ -22,20 +22,20 @@ import org.jetbrains.annotations.NotNull;
 /**
  * @author svtk
  */
-public class DiagnosticFactory<E extends PsiElement> extends DiagnosticFactoryWithPsiElement<E> {
+public class SimpleDiagnosticFactory<E extends PsiElement> extends DiagnosticFactoryWithPsiElement<E> {
     protected final String message;
 
-    protected DiagnosticFactory(Severity severity, String message, PositioningStrategy<? super E> positioningStrategy) {
+    protected SimpleDiagnosticFactory(Severity severity, String message, PositioningStrategy<? super E> positioningStrategy) {
         super(severity, positioningStrategy);
         this.message = message;
     }
 
-    public static <T extends PsiElement> DiagnosticFactory<T> create(Severity severity, String message) {
+    public static <T extends PsiElement> SimpleDiagnosticFactory<T> create(Severity severity, String message) {
         return create(severity, message, PositioningStrategies.DEFAULT);
     }
 
-    public static <T extends PsiElement> DiagnosticFactory<T> create(Severity severity, String message, PositioningStrategy<? super T> positioningStrategy) {
-        return new DiagnosticFactory<T>(severity, message, positioningStrategy);
+    public static <T extends PsiElement> SimpleDiagnosticFactory<T> create(Severity severity, String message, PositioningStrategy<? super T> positioningStrategy) {
+        return new SimpleDiagnosticFactory<T>(severity, message, positioningStrategy);
     }
 
     String getMessage() {
@@ -44,6 +44,6 @@ public class DiagnosticFactory<E extends PsiElement> extends DiagnosticFactoryWi
 
     @NotNull
     public ParametrizedDiagnostic<E> on(@NotNull E element) {
-        return new DiagnosticWithPsiElement<E>(element, this, severity);
+        return new SimpleDiagnostic<E>(element, this, severity);
     }
 }
\ No newline at end of file