Generate copy function for data classes

#KT-2779 Fixed

compiler/frontend/src/org/jetbrains/jet/lang/resolve/BindingContext.java

@@ -238,6 +238,8 @@ public interface BindingContext {
 
     WritableSlice<ValueParameterDescriptor, FunctionDescriptor> DATA_CLASS_COMPONENT_FUNCTION =
             Slices.<ValueParameterDescriptor, FunctionDescriptor>sliceBuilder().build();
+    WritableSlice<ClassDescriptor, FunctionDescriptor> DATA_CLASS_COPY_FUNCTION =
+            Slices.<ClassDescriptor, FunctionDescriptor>sliceBuilder().build();
 
     WritableSlice<FqName, ClassDescriptor> FQNAME_TO_CLASS_DESCRIPTOR = new BasicWritableSlice<FqName, ClassDescriptor>(DO_NOTHING, true);
     WritableSlice<FqName, NamespaceDescriptor> FQNAME_TO_NAMESPACE_DESCRIPTOR =

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DeclarationResolver.java

@@ -91,7 +91,7 @@ public class DeclarationResolver {
         resolveConstructorHeaders();
         resolveAnnotationStubsOnClassesAndConstructors();
         resolveFunctionAndPropertyHeaders();
-        createComponentFunctionsForDataClasses();
+        createFunctionsForDataClasses();
         importsResolver.processMembersImports(rootScope);
         checkRedeclarationsInNamespaces();
         checkRedeclarationsInInnerClassNames();
@@ -219,24 +219,22 @@ public class DeclarationResolver {
         }
     }
 
-    private void createComponentFunctionsForDataClasses() {
+    private void createFunctionsForDataClasses() {
         for (Map.Entry<JetClass, MutableClassDescriptor> entry : context.getClasses().entrySet()) {
             JetClass jetClass = entry.getKey();
             MutableClassDescriptor classDescriptor = entry.getValue();
 
             if (jetClass.hasPrimaryConstructor() && KotlinBuiltIns.getInstance().isData(classDescriptor)) {
-                createComponentFunctions(classDescriptor);
+                ConstructorDescriptor constructor = DescriptorUtils.getConstructorOfDataClass(classDescriptor);
+                createComponentFunctions(classDescriptor, constructor);
+                createCopyFunction(classDescriptor, constructor);
             }
         }
     }
 
-    private void createComponentFunctions(MutableClassDescriptor classDescriptor) {
-        Set<ConstructorDescriptor> constructors = classDescriptor.getConstructors();
-        assert constructors.size() == 1 : "Data class hasn't a single constructor: " + constructors.size();
-        ConstructorDescriptor constructor = constructors.iterator().next();
-
+    private void createComponentFunctions(@NotNull MutableClassDescriptor classDescriptor, @NotNull ConstructorDescriptor constructorDescriptor) {
         int parameterIndex = 0;
-        for (ValueParameterDescriptor parameter : constructor.getValueParameters()) {
+        for (ValueParameterDescriptor parameter : constructorDescriptor.getValueParameters()) {
             if (!ErrorUtils.isErrorType(parameter.getType())) {
                 PropertyDescriptor property = trace.get(BindingContext.VALUE_PARAMETER_AS_PROPERTY, parameter);
                 if (property != null) {
@@ -251,6 +249,13 @@ public class DeclarationResolver {
         }
     }
 
+    private void createCopyFunction(@NotNull MutableClassDescriptor classDescriptor, @NotNull ConstructorDescriptor constructorDescriptor) {
+        SimpleFunctionDescriptor functionDescriptor = DescriptorResolver.createCopyFunctionDescriptor(
+                constructorDescriptor.getValueParameters(), classDescriptor, trace);
+
+        classDescriptor.getBuilder().addFunctionDescriptor(functionDescriptor);
+    }
+
     private void processPrimaryConstructor(MutableClassDescriptor classDescriptor, JetClass klass) {
         if (classDescriptor.getKind() == ClassKind.TRAIT) {
             JetParameterList primaryConstructorParameterList = klass.getPrimaryConstructorParameterList();
@@ -356,8 +361,8 @@ public class DeclarationResolver {
                     descriptorMap.put(desc.getName(), desc);
                 }
             }
-            
-           reportRedeclarations(descriptorMap); 
+
+           reportRedeclarations(descriptorMap);
         }
     }
 
@@ -392,5 +397,5 @@ public class DeclarationResolver {
         }
     }
 
-    
+
 }

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DescriptorResolver.java

@@ -57,6 +57,7 @@ import static org.jetbrains.jet.lexer.JetTokens.OVERRIDE_KEYWORD;
 public class DescriptorResolver {
     public static final Name VALUE_OF_METHOD_NAME = Name.identifier("valueOf");
     public static final Name VALUES_METHOD_NAME = Name.identifier("values");
+    public static final Name COPY_METHOD_NAME = Name.identifier("copy");
     public static final String COMPONENT_FUNCTION_NAME_PREFIX = "component";
 
     @NotNull
@@ -349,6 +350,53 @@ public class DescriptorResolver {
         return functionDescriptor;
     }
 
+    @NotNull
+    public static SimpleFunctionDescriptor createCopyFunctionDescriptor(
+            @NotNull Collection<ValueParameterDescriptor> constructorParameters,
+            @NotNull ClassDescriptor classDescriptor,
+            @NotNull BindingTrace trace
+    ) {
+        JetType returnType = classDescriptor.getDefaultType();
+
+        SimpleFunctionDescriptorImpl functionDescriptor = new SimpleFunctionDescriptorImpl(
+                classDescriptor,
+                Collections.<AnnotationDescriptor>emptyList(),
+                COPY_METHOD_NAME,
+                CallableMemberDescriptor.Kind.SYNTHESIZED
+        );
+
+        List<ValueParameterDescriptor> parameterDescriptors = Lists.newArrayList();
+
+        for (ValueParameterDescriptor parameter : constructorParameters) {
+            PropertyDescriptor propertyDescriptor = trace.getBindingContext().get(BindingContext.VALUE_PARAMETER_AS_PROPERTY, parameter);
+            // If parameter hasn't corresponding property, so it mustn't have default value as a parameter in copy function for data class
+            boolean declaresDefaultValue = propertyDescriptor != null;
+            ValueParameterDescriptorImpl parameterDescriptor =
+                    new ValueParameterDescriptorImpl(functionDescriptor, parameter.getIndex(), parameter.getAnnotations(),
+                                                     parameter.getName(), parameter.isVar(), parameter.getType(),
+                                                     declaresDefaultValue,
+                                                     parameter.getVarargElementType());
+            parameterDescriptors.add(parameterDescriptor);
+            if (declaresDefaultValue) {
+                trace.record(BindingContext.VALUE_PARAMETER_AS_PROPERTY, parameterDescriptor, propertyDescriptor);
+            }
+        }
+
+        functionDescriptor.initialize(
+                null,
+                classDescriptor.getImplicitReceiver(),
+                Collections.<TypeParameterDescriptor>emptyList(),
+                parameterDescriptors,
+                returnType,
+                Modality.FINAL,
+                classDescriptor.getVisibility(),
+                true
+        );
+
+        trace.record(BindingContext.DATA_CLASS_COPY_FUNCTION, classDescriptor, functionDescriptor);
+        return functionDescriptor;
+    }
+
     public static Visibility getDefaultVisibility(JetModifierListOwner modifierListOwner, DeclarationDescriptor containingDescriptor) {
         Visibility defaultVisibility;
         if (containingDescriptor instanceof ClassDescriptor) {

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DescriptorUtils.java

@@ -365,4 +365,10 @@ public class DescriptorUtils {
                 + (classifier == null ? "null" : classifier.getClass());
         return (ClassDescriptor) classifier;
     }
+
+    public static ConstructorDescriptor getConstructorOfDataClass(ClassDescriptor classDescriptor) {
+        Collection<ConstructorDescriptor> constructors = classDescriptor.getConstructors();
+        assert constructors.size() == 1 : "Data class must have only one constructor: " + constructors;
+        return constructors.iterator().next();
+    }
 }

compiler/frontend/src/org/jetbrains/jet/lang/resolve/lazy/LazyClassMemberScope.java

@@ -174,6 +174,12 @@ public class LazyClassMemberScope extends AbstractLazyMemberScope<LazyClassDescr
                 break;
             }
         }
+        if (!constructor.getValueParameters().isEmpty() && name.equals(DescriptorResolver.COPY_METHOD_NAME)) {
+            SimpleFunctionDescriptor copyFunctionDescriptor = DescriptorResolver.createCopyFunctionDescriptor(
+                    constructor.getValueParameters(),
+                    thisDescriptor, resolveSession.getTrace());
+            result.add(copyFunctionDescriptor);
+        }
     }
 
     private void generateEnumClassObjectMethods(@NotNull Collection<? super FunctionDescriptor> result, @NotNull Name name) {
@@ -307,6 +313,7 @@ public class LazyClassMemberScope extends AbstractLazyMemberScope<LazyClassDescr
             if (functions.isEmpty()) break;
             n++;
         }
+        getFunctions(Name.identifier("copy"));
     }
 
     @Override