Generate copy() in data class even if constructor is empty or not present

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

@@ -227,10 +227,14 @@ public class DeclarationResolver {
             JetClassOrObject klass = entry.getKey();
             MutableClassDescriptor classDescriptor = (MutableClassDescriptor) entry.getValue();
 
-            if (klass instanceof JetClass && klass.hasPrimaryConstructor() && KotlinBuiltIns.getInstance().isData(classDescriptor)) {
-                ConstructorDescriptor constructor = getConstructorOfDataClass(classDescriptor);
-                createComponentFunctions(classDescriptor, constructor);
-                createCopyFunction(classDescriptor, constructor);
+            if (klass instanceof JetClass && KotlinBuiltIns.getInstance().isData(classDescriptor)) {
+                List<ValueParameterDescriptor> parameters =
+                        klass.hasPrimaryConstructor() ?
+                        getConstructorOfDataClass(classDescriptor).getValueParameters() :
+                        Collections.<ValueParameterDescriptor>emptyList();
+
+                createComponentFunctions(classDescriptor, parameters);
+                createCopyFunction(classDescriptor, parameters);
             }
         }
     }
@@ -242,9 +246,9 @@ public class DeclarationResolver {
         return constructors.iterator().next();
     }
 
-    private void createComponentFunctions(@NotNull MutableClassDescriptor classDescriptor, @NotNull ConstructorDescriptor constructorDescriptor) {
+    private void createComponentFunctions(@NotNull MutableClassDescriptor classDescriptor, List<ValueParameterDescriptor> parameters) {
         int parameterIndex = 0;
-        for (ValueParameterDescriptor parameter : constructorDescriptor.getValueParameters()) {
+        for (ValueParameterDescriptor parameter : parameters) {
             if (!parameter.getType().isError()) {
                 PropertyDescriptor property = trace.get(BindingContext.VALUE_PARAMETER_AS_PROPERTY, parameter);
                 if (property != null) {
@@ -259,9 +263,9 @@ public class DeclarationResolver {
         }
     }
 
-    private void createCopyFunction(@NotNull MutableClassDescriptor classDescriptor, @NotNull ConstructorDescriptor constructorDescriptor) {
+    private void createCopyFunction(@NotNull MutableClassDescriptor classDescriptor, List<ValueParameterDescriptor> parameters) {
         SimpleFunctionDescriptor functionDescriptor = DescriptorResolver.createCopyFunctionDescriptor(
-                constructorDescriptor.getValueParameters(), classDescriptor, trace);
+                parameters, classDescriptor, trace);
 
         classDescriptor.getBuilder().addFunctionDescriptor(functionDescriptor);
     }

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

@@ -175,7 +175,7 @@ public class LazyClassMemberScope extends AbstractLazyMemberScope<LazyClassDescr
                 break;
             }
         }
-        if (!constructor.getValueParameters().isEmpty() && name.equals(DescriptorResolver.COPY_METHOD_NAME)) {
+        if (name.equals(DescriptorResolver.COPY_METHOD_NAME)) {
             SimpleFunctionDescriptor copyFunctionDescriptor = DescriptorResolver.createCopyFunctionDescriptor(
                     constructor.getValueParameters(),
                     thisDescriptor, trace);

compiler/testData/diagnostics/tests/dataClasses/noConstructor.kt

@@ -0,0 +1,6 @@
+data class A
+
+fun foo(a: A) {
+    a.<!UNRESOLVED_REFERENCE!>component1<!>()
+    a.<!UNRESOLVED_REFERENCE!>component2<!>()
+}

compiler/testData/loadJava/compiledKotlin/dataClass/NoComponents.kt

@@ -1,3 +1,4 @@
 package test
 
 data class DataClass
+data class OtherDataClass()

compiler/testData/loadJava/compiledKotlin/dataClass/NoComponents.txt

@@ -2,4 +2,10 @@ package test
 
 kotlin.data() internal final class DataClass {
     /*primary*/ public constructor DataClass()
+    internal final /*synthesized*/ fun copy(): test.DataClass
+}
+
+kotlin.data() internal final class OtherDataClass {
+    /*primary*/ public constructor OtherDataClass()
+    internal final /*synthesized*/ fun copy(): test.OtherDataClass
 }

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -2127,6 +2127,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
             
+            @TestMetadata("noConstructor.kt")
+            public void testNoConstructor() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/dataClasses/noConstructor.kt");
+                doTest(fileName);
+            }
+            
             @TestMetadata("notADataClass.kt")
             public void testNotADataClass() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/dataClasses/notADataClass.kt");