Generate synthetic methods for annotated properties in TImpl classes

Traits themselves can't have these methods, since it'd be a weird public method
in an interface

 #KT-4072 Fixed

compiler/backend/src/org/jetbrains/jet/codegen/ClassBodyCodegen.java

@@ -79,8 +79,7 @@ public abstract class ClassBodyCodegen extends MemberCodegen {
     protected void generateKotlinAnnotation() {
     }
 
-    protected void generateSyntheticParts() {
-    }
+    protected abstract void generateSyntheticParts();
 
     private void generateClassBody() {
         FunctionCodegen functionCodegen = new FunctionCodegen(context, v, state, this);

compiler/backend/src/org/jetbrains/jet/codegen/PropertyCodegen.java

@@ -27,7 +27,6 @@ import org.jetbrains.asm4.commons.InstructionAdapter;
 import org.jetbrains.asm4.commons.Method;
 import org.jetbrains.jet.codegen.context.CodegenContext;
 import org.jetbrains.jet.codegen.context.FieldOwnerContext;
-import org.jetbrains.jet.codegen.context.NamespaceContext;
 import org.jetbrains.jet.codegen.context.NamespaceFacadeContext;
 import org.jetbrains.jet.codegen.signature.JvmMethodSignature;
 import org.jetbrains.jet.codegen.state.GenerationState;
@@ -49,6 +48,7 @@ import static org.jetbrains.asm4.Opcodes.*;
 import static org.jetbrains.jet.codegen.AsmUtil.*;
 import static org.jetbrains.jet.codegen.CodegenUtil.getParentBodyCodegen;
 import static org.jetbrains.jet.codegen.CodegenUtil.isInterface;
+import static org.jetbrains.jet.lang.resolve.DescriptorUtils.isTrait;
 import static org.jetbrains.jet.lang.resolve.java.AsmTypeConstants.OBJECT_TYPE;
 
 public class PropertyCodegen extends GenerationStateAware {
@@ -142,26 +142,41 @@ public class PropertyCodegen extends GenerationStateAware {
             AnnotationCodegen.forField(fieldVisitor, typeMapper).genAnnotations(propertyDescriptor);
         }
         else if (!propertyDescriptor.getAnnotations().isEmpty()) {
-            // Annotations on properties without backing fields are stored in bytecode on an empty synthetic method. This way they're still
-            // accessible via reflection, and 'deprecated' and 'private' flags prevent this method from being called accidentally
-            ReceiverParameterDescriptor receiver = propertyDescriptor.getReceiverParameter();
-            Type receiverAsmType = receiver == null ? null : typeMapper.mapType(receiver.getType());
-            Method method = JvmAbi.getSyntheticMethodSignatureForAnnotatedProperty(propertyDescriptor.getName(), receiverAsmType);
-
-            MethodVisitor mv = v.newMethod(null,
-                                           ACC_DEPRECATED | ACC_FINAL | ACC_PRIVATE | ACC_STATIC | ACC_SYNTHETIC,
-                                           method.getName(),
-                                           method.getDescriptor(),
-                                           null,
-                                           null);
-            v.getMemberMap().recordSyntheticMethodOfProperty(propertyDescriptor, method);
-            AnnotationCodegen.forMethod(mv, typeMapper).genAnnotations(propertyDescriptor);
-            mv.visitCode();
-            mv.visitInsn(Opcodes.RETURN);
-            mv.visitEnd();
+            if (!isTrait(context.getContextDescriptor())) {
+                Method method = getSyntheticMethodSignature(typeMapper, propertyDescriptor);
+                generateSyntheticMethodForAnnotatedProperty(v, typeMapper, propertyDescriptor, method);
+                v.getMemberMap().recordSyntheticMethodOfProperty(propertyDescriptor, method);
+            }
         }
     }
 
+    // Annotations on properties without backing fields are stored in bytecode on an empty synthetic method. This way they're still
+    // accessible via reflection, and 'deprecated' and 'private' flags prevent this method from being called accidentally
+    public static void generateSyntheticMethodForAnnotatedProperty(
+            @NotNull ClassBuilder v,
+            @NotNull JetTypeMapper typeMapper,
+            @NotNull PropertyDescriptor propertyDescriptor,
+            @NotNull Method method
+    ) {
+        MethodVisitor mv = v.newMethod(null,
+                                       ACC_DEPRECATED | ACC_FINAL | ACC_PRIVATE | ACC_STATIC | ACC_SYNTHETIC,
+                                       method.getName(),
+                                       method.getDescriptor(),
+                                       null,
+                                       null);
+        AnnotationCodegen.forMethod(mv, typeMapper).genAnnotations(propertyDescriptor);
+        mv.visitCode();
+        mv.visitInsn(Opcodes.RETURN);
+        mv.visitEnd();
+    }
+
+    @NotNull
+    public static Method getSyntheticMethodSignature(@NotNull JetTypeMapper typeMapper, @NotNull PropertyDescriptor propertyDescriptor) {
+        ReceiverParameterDescriptor receiver = propertyDescriptor.getReceiverParameter();
+        Type receiverAsmType = receiver == null ? null : typeMapper.mapType(receiver.getType());
+        return JvmAbi.getSyntheticMethodSignatureForAnnotatedProperty(propertyDescriptor.getName(), receiverAsmType);
+    }
+
     private FieldVisitor generateBackingField(JetNamedDeclaration element, PropertyDescriptor propertyDescriptor, boolean isDelegate, JetType jetType, Object defaultValue) {
         int modifiers = getDeprecatedAccessFlag(propertyDescriptor);
 

compiler/backend/src/org/jetbrains/jet/codegen/TraitImplBodyCodegen.java

@@ -18,10 +18,16 @@ package org.jetbrains.jet.codegen;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.asm4.commons.Method;
 import org.jetbrains.jet.codegen.context.ClassContext;
 import org.jetbrains.jet.codegen.state.GenerationState;
 import org.jetbrains.jet.codegen.state.JetTypeMapperMode;
+import org.jetbrains.jet.lang.descriptors.PropertyDescriptor;
+import org.jetbrains.jet.lang.descriptors.VariableDescriptor;
 import org.jetbrains.jet.lang.psi.JetClassOrObject;
+import org.jetbrains.jet.lang.psi.JetDeclaration;
+import org.jetbrains.jet.lang.psi.JetProperty;
+import org.jetbrains.jet.lang.resolve.BindingContext;
 
 import static org.jetbrains.asm4.Opcodes.*;
 
@@ -49,6 +55,25 @@ public class TraitImplBodyCodegen extends ClassBodyCodegen {
         v.visitSource(myClass.getContainingFile().getName(), null);
     }
 
+    @Override
+    protected void generateSyntheticParts() {
+        generateSyntheticMethodsForAnnotatedProperties();
+    }
+
+    private void generateSyntheticMethodsForAnnotatedProperties() {
+        for (JetDeclaration declaration : myClass.getDeclarations()) {
+            if (declaration instanceof JetProperty) {
+                VariableDescriptor variable = bindingContext.get(BindingContext.VARIABLE, declaration);
+                assert variable instanceof PropertyDescriptor : "Variable in trait should be a property: " + variable;
+                PropertyDescriptor property = (PropertyDescriptor) variable;
+                if (!property.getAnnotations().isEmpty()) {
+                    Method method = PropertyCodegen.getSyntheticMethodSignature(typeMapper, property);
+                    PropertyCodegen.generateSyntheticMethodForAnnotatedProperty(v, typeMapper, property, method);
+                }
+            }
+        }
+    }
+
     @NotNull
     private String jvmName() {
         return typeMapper.mapType(descriptor.getDefaultType(), JetTypeMapperMode.TRAIT_IMPL).getInternalName();

compiler/testData/codegen/properties/syntheticMethod/inTrait.kt

@@ -0,0 +1,7 @@
+import java.lang.annotation.*
+
+Retention(RetentionPolicy.RUNTIME) annotation class SomeAnnotation(val value: String)
+
+trait T {
+    [SomeAnnotation("OK")] val property: Int
+}

compiler/tests/org/jetbrains/jet/codegen/SyntheticMethodForAnnotatedPropertyGenTest.java

@@ -45,7 +45,7 @@ public class SyntheticMethodForAnnotatedPropertyGenTest extends CodegenTestCase
 
     public void testInClass() {
         loadFile();
-        assertClassHasAnnotatedSyntheticMethod(generateClass("A"));
+        assertAnnotatedSyntheticMethodExistence(true, generateClass("A"));
     }
 
     public void testTopLevel() {
@@ -55,14 +55,24 @@ public class SyntheticMethodForAnnotatedPropertyGenTest extends CodegenTestCase
             if (fileName.startsWith(packageClassName) && !fileName.equals(packageClassName + ".class")) {
                 // This should be package$src class
                 Class<?> a = generateClass(fileName.substring(0, fileName.length() - ".class".length()));
-                assertClassHasAnnotatedSyntheticMethod(a);
+                assertAnnotatedSyntheticMethodExistence(true, a);
             }
         }
     }
 
-    private static void assertClassHasAnnotatedSyntheticMethod(@NotNull Class<?> a) {
-        for (Method method : a.getDeclaredMethods()) {
+    public void testInTrait() throws ClassNotFoundException {
+        loadFile();
+        GeneratedClassLoader loader = generateAndCreateClassLoader();
+        assertAnnotatedSyntheticMethodExistence(false, loader.loadClass("T"));
+        assertAnnotatedSyntheticMethodExistence(true, loader.loadClass("T" + JvmAbi.TRAIT_IMPL_SUFFIX));
+    }
+
+    private static void assertAnnotatedSyntheticMethodExistence(boolean expected, @NotNull Class<?> clazz) {
+        for (Method method : clazz.getDeclaredMethods()) {
             if (TEST_SYNTHETIC_METHOD_NAME.equals(method.getName())) {
+                if (!expected) {
+                    fail("Synthetic method for annotated property found, but not expected: " + method);
+                }
                 assertTrue(method.isSynthetic());
                 int modifiers = method.getModifiers();
                 assertTrue(Modifier.isFinal(modifiers));
@@ -75,6 +85,8 @@ public class SyntheticMethodForAnnotatedPropertyGenTest extends CodegenTestCase
                 return;
             }
         }
-        fail("Synthetic method for annotated property not found: " + TEST_SYNTHETIC_METHOD_NAME);
+        if (expected) {
+            fail("Synthetic method for annotated property expected, but not found: " + TEST_SYNTHETIC_METHOD_NAME);
+        }
     }
 }