"field": synthetic variable creation in accessors, codegen changed accordingly, a set of tests, relevant code fix (j2k)

compiler/backend/src/org/jetbrains/kotlin/codegen/ExpressionCodegen.java

@@ -47,6 +47,7 @@ import org.jetbrains.kotlin.codegen.when.SwitchCodegen;
 import org.jetbrains.kotlin.codegen.when.SwitchCodegenUtil;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.impl.ScriptCodeDescriptor;
+import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor;
 import org.jetbrains.kotlin.diagnostics.DiagnosticUtils;
 import org.jetbrains.kotlin.diagnostics.Errors;
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation;
@@ -58,10 +59,7 @@ import org.jetbrains.kotlin.load.java.descriptors.SamConstructorDescriptor;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.renderer.DescriptorRenderer;
-import org.jetbrains.kotlin.resolve.BindingContext;
-import org.jetbrains.kotlin.resolve.BindingContextUtils;
-import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils;
-import org.jetbrains.kotlin.resolve.DescriptorUtils;
+import org.jetbrains.kotlin.resolve.*;
 import org.jetbrains.kotlin.resolve.annotations.AnnotationsPackage;
 import org.jetbrains.kotlin.resolve.calls.callResolverUtil.CallResolverUtilPackage;
 import org.jetbrains.kotlin.resolve.calls.model.*;
@@ -1981,6 +1979,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
         assert descriptor != null : "Couldn't find descriptor for '" + expression.getText() + "'";
         descriptor = descriptor.getOriginal();
 
+        boolean isSyntheticField = descriptor instanceof SyntheticFieldDescriptor;
+        if (isSyntheticField) {
+            descriptor = ((SyntheticFieldDescriptor) descriptor).getPropertyDescriptor();
+        }
         if (descriptor instanceof CallableMemberDescriptor) {
             CallableMemberDescriptor memberDescriptor = DescriptorUtils.unwrapFakeOverride((CallableMemberDescriptor) descriptor);
 
@@ -2009,7 +2011,8 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
             }
 
             boolean directToField =
-                    expression.getReferencedNameElementType() == JetTokens.FIELD_IDENTIFIER && contextKind() != OwnerKind.TRAIT_IMPL;
+                    (expression.getReferencedNameElementType() == JetTokens.FIELD_IDENTIFIER || isSyntheticField)
+                    && contextKind() != OwnerKind.TRAIT_IMPL;
             JetSuperExpression superExpression =
                     resolvedCall == null ? null : CallResolverUtilPackage.getSuperCallExpression(resolvedCall.getCall());
             propertyDescriptor = context.accessibleDescriptor(propertyDescriptor, superExpression);

compiler/frontend/src/org/jetbrains/kotlin/descriptors/impl/SyntheticFieldDescriptor.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.descriptors.impl
+
+import org.jetbrains.kotlin.descriptors.PropertyAccessorDescriptor
+import org.jetbrains.kotlin.descriptors.PropertyDescriptor
+import org.jetbrains.kotlin.descriptors.annotations.Annotations
+import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.psi.JetProperty
+import org.jetbrains.kotlin.resolve.source.toSourceElement
+
+class SyntheticFieldDescriptor private constructor(
+        val propertyDescriptor: PropertyDescriptor,
+        accessorDescriptor: PropertyAccessorDescriptor,
+        property: JetProperty
+): LocalVariableDescriptor(accessorDescriptor, Annotations.EMPTY, SyntheticFieldDescriptor.NAME,
+                           propertyDescriptor.type, propertyDescriptor.isVar, property.toSourceElement()) {
+
+    constructor(accessorDescriptor: PropertyAccessorDescriptor,
+                property: JetProperty): this(accessorDescriptor.correspondingProperty, accessorDescriptor, property)
+
+    override fun getDispatchReceiverParameter() = propertyDescriptor.dispatchReceiverParameter
+
+    companion object {
+        val NAME = Name.identifier("field")
+    }
+}

compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java

@@ -25,7 +25,11 @@ import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.*;
+import org.jetbrains.kotlin.descriptors.annotations.Annotations;
+import org.jetbrains.kotlin.descriptors.impl.LocalVariableDescriptor;
+import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor;
 import org.jetbrains.kotlin.lexer.JetTokens;
+import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.psi.psiUtil.PsiUtilPackage;
 import org.jetbrains.kotlin.resolve.calls.CallResolver;
@@ -37,6 +41,7 @@ import org.jetbrains.kotlin.resolve.calls.util.CallMaker;
 import org.jetbrains.kotlin.resolve.lazy.ForceResolveUtil;
 import org.jetbrains.kotlin.resolve.scopes.*;
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue;
+import org.jetbrains.kotlin.resolve.source.KotlinSourceElementKt;
 import org.jetbrains.kotlin.types.*;
 import org.jetbrains.kotlin.types.expressions.ExpressionTypingContext;
 import org.jetbrains.kotlin.types.expressions.ExpressionTypingServices;
@@ -649,6 +654,9 @@ public class BodyResolver {
                             trace.record(BindingContext.BACKING_FIELD_REQUIRED, propertyDescriptor); // TODO: this trace?
                         }
                     }
+                    if (descriptor instanceof SyntheticFieldDescriptor) {
+                        trace.record(BindingContext.BACKING_FIELD_REQUIRED, propertyDescriptor);
+                    }
                 }
             }
         });
@@ -766,6 +774,16 @@ public class BodyResolver {
                         trace, innerScope, outerDataFlowInfo, NO_EXPECTED_TYPE, callChecker)
         );
 
+        // Synthetic "field" creation
+        if (functionDescriptor instanceof PropertyAccessorDescriptor) {
+            assert innerScope instanceof WritableScopeStorage : "Expected innerScope as WritableScopeStorage but got " + innerScope;
+            PropertyAccessorDescriptor accessorDescriptor = (PropertyAccessorDescriptor) functionDescriptor;
+            JetProperty property = (JetProperty) function.getParent();
+            SyntheticFieldDescriptor fieldDescriptor = new SyntheticFieldDescriptor(accessorDescriptor, property);
+            WritableScopeStorage innerScopeStorage = (WritableScopeStorage) innerScope;
+            innerScopeStorage.addVariableOrClassDescriptor(fieldDescriptor);
+        }
+
         DataFlowInfo dataFlowInfo = null;
 
         if (beforeBlockBody != null) {

compiler/testData/codegen/box/properties/field.kt

@@ -0,0 +1,10 @@
+var my: String = ""
+    get() = field + "K"
+    set(arg) {
+        field = arg
+    }
+
+fun box(): String {
+    my = "O"
+    return my
+}

compiler/testData/codegen/box/properties/fieldInClass.kt

@@ -0,0 +1,6 @@
+class My {
+    val my: String = "O"
+        get() = field + "K"
+}
+
+fun box() = My().my

compiler/testData/codegen/box/properties/fieldInsideField.kt

@@ -0,0 +1,13 @@
+abstract class Your {
+    abstract val your: String
+
+    fun foo() = your
+}
+
+val my: String = "O"
+    get() = field + object: Your() {
+        override val your = "K"
+            get() = field
+    }.foo()
+
+fun box() = my

compiler/testData/codegen/box/properties/fieldInsideNested.kt

@@ -0,0 +1,12 @@
+abstract class Your {
+    abstract val your: String
+
+    fun foo() = your
+}
+
+val my: String = "O"
+    get() = object: Your() {
+        override val your = field
+    }.foo() + "K"
+
+fun box() = my

compiler/testData/codegen/box/properties/fieldSimple.kt

@@ -0,0 +1,4 @@
+val x: String = "OK"
+    get() = field
+
+fun box() = x

compiler/testData/diagnostics/tests/backingField/FieldAsProperty.kt

@@ -0,0 +1,9 @@
+class My(val field: Int) {
+    // Backing field, initializer
+    val second: Int = 0
+        get() = field
+
+    // No backing field, no initializer
+    val third: Int
+        get() = this.field
+}

compiler/testData/diagnostics/tests/backingField/FieldAsProperty.txt

@@ -0,0 +1,11 @@
+package
+
+public final class My {
+    public constructor My(/*0*/ field: kotlin.Int)
+    public final val field: kotlin.Int
+    public final val second: kotlin.Int = 0
+    public final val third: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/backingField/FieldDerived.kt

@@ -0,0 +1,18 @@
+open class Base {
+    open val x: Int = 1
+        get() = field - 1
+}
+
+class Other: Base() {
+    override val x = 2
+}
+
+class Another: Base() {
+    override val x = 3
+        get() = field + 1
+}
+
+class NoBackingField: Base() {
+    override val x: Int
+        get() = 5
+}

compiler/testData/diagnostics/tests/backingField/FieldDerived.txt

@@ -0,0 +1,33 @@
+package
+
+public final class Another : Base {
+    public constructor Another()
+    public open override /*1*/ val x: kotlin.Int = 3
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public open class Base {
+    public constructor Base()
+    public open val x: kotlin.Int = 1
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class NoBackingField : Base {
+    public constructor NoBackingField()
+    public open override /*1*/ val x: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Other : Base {
+    public constructor Other()
+    public open override /*1*/ val x: kotlin.Int = 2
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/backingField/FieldInInterface.kt

@@ -0,0 +1,4 @@
+interface My {
+    <!BACKING_FIELD_IN_TRAIT!>val x: Int<!> = <!PROPERTY_INITIALIZER_IN_TRAIT!>0<!>
+        get() = field
+}

compiler/testData/diagnostics/tests/backingField/FieldInInterface.txt

@@ -0,0 +1,8 @@
+package
+
+public interface My {
+    public open val x: kotlin.Int = 0
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/backingField/FieldInLocal.kt

@@ -0,0 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE
+fun foo() {
+    open class Local {
+        val my: Int = 2
+            get() = field
+    }
+    val your = object: Local() {
+        val your: Int = 3
+            get() = field
+    }
+}

compiler/testData/diagnostics/tests/backingField/FieldInLocal.txt

@@ -0,0 +1,3 @@
+package
+
+public fun foo(): kotlin.Unit

compiler/testData/diagnostics/tests/backingField/FieldOnVal.kt

@@ -0,0 +1,2 @@
+val my: Int = 21
+    get() = field * 2

compiler/testData/diagnostics/tests/backingField/FieldOnVal.txt

@@ -0,0 +1,3 @@
+package
+
+public val my: kotlin.Int = 21

compiler/testData/diagnostics/tests/backingField/FieldOnVar.kt

@@ -0,0 +1,5 @@
+var my: Int = 0
+    get() = -field
+    set(arg) {
+        field = arg
+    }

compiler/testData/diagnostics/tests/backingField/FieldOnVar.txt

@@ -0,0 +1,3 @@
+package
+
+public var my: kotlin.Int

compiler/testData/diagnostics/tests/backingField/FieldShadow.kt

@@ -0,0 +1,8 @@
+class My {
+    // No initialization needed because no backing field
+    val two: Int
+        get() {
+            val <!NAME_SHADOWING!>field<!> = 2
+            return field
+        }
+}

compiler/testData/diagnostics/tests/backingField/FieldShadow.txt

@@ -0,0 +1,9 @@
+package
+
+public final class My {
+    public constructor My()
+    public final val two: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

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

@@ -1326,6 +1326,48 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("FieldAsProperty.kt")
+            public void testFieldAsProperty() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldAsProperty.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("FieldDerived.kt")
+            public void testFieldDerived() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldDerived.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("FieldInInterface.kt")
+            public void testFieldInInterface() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldInInterface.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("FieldInLocal.kt")
+            public void testFieldInLocal() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldInLocal.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("FieldOnVal.kt")
+            public void testFieldOnVal() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldOnVal.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("FieldOnVar.kt")
+            public void testFieldOnVar() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldOnVar.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("FieldShadow.kt")
+            public void testFieldShadow() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldShadow.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("kt462BackingFieldsResolve.kt")
             public void testKt462BackingFieldsResolve() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/kt462BackingFieldsResolve.kt");

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -6337,6 +6337,36 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
+        @TestMetadata("field.kt")
+        public void testField() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/field.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("fieldInClass.kt")
+        public void testFieldInClass() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/fieldInClass.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("fieldInsideField.kt")
+        public void testFieldInsideField() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/fieldInsideField.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("fieldInsideNested.kt")
+        public void testFieldInsideNested() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/fieldInsideNested.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("fieldSimple.kt")
+        public void testFieldSimple() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/fieldSimple.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("generalAccess.kt")
         public void testGeneralAccess() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/generalAccess.kt");

idea/ide-common/src/org/jetbrains/kotlin/idea/codeInsight/ReferenceVariantsHelper.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor
 import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
 import org.jetbrains.kotlin.idea.resolve.frontendService
 import org.jetbrains.kotlin.idea.util.CallType
@@ -156,7 +157,7 @@ public class ReferenceVariantsHelper(
             // process non-instance members
             for (descriptor in resolutionScope.getDescriptorsFiltered(kindFilter, nameFilter)) {
                 if (descriptor is CallableDescriptor) {
-                    assert(descriptor.dispatchReceiverParameter == null) {
+                    assert(descriptor is SyntheticFieldDescriptor || descriptor.dispatchReceiverParameter == null) {
                         "Resolution scope with member descriptor: $descriptor. Scope structure: ${JetScopeUtils.printStructure(resolutionScope)}"
                     }
                 }
@@ -270,7 +271,7 @@ public class ReferenceVariantsHelper(
         }
 
         for (descriptor in resolutionScope.getDescriptors(kindFilter exclude DescriptorKindExclude.NonExtensions, nameFilter)) {
-            assert(descriptor !is CallableDescriptor || descriptor.dispatchReceiverParameter == null) {
+            assert(descriptor !is CallableDescriptor || descriptor is SyntheticFieldDescriptor || descriptor.dispatchReceiverParameter == null) {
                 "Resolution scope with member descriptor: $descriptor. Scope structure: ${JetScopeUtils.printStructure(resolutionScope)}"
             }
             if (descriptor.isExtension) {

j2k/src/org/jetbrains/kotlin/j2k/usageProcessing/FieldToPropertyProcessing.kt

@@ -25,7 +25,7 @@ import org.jetbrains.kotlin.psi.JetPsiFactory
 import org.jetbrains.kotlin.psi.JetSimpleNameExpression
 
 class FieldToPropertyProcessing(val field: PsiField, val propertyName: String, val isNullable: Boolean) : UsageProcessing {
-    override val targetElement: PsiElement get() = field
+    override val targetElement: PsiElement get() = this.field
 
     override val convertedCodeProcessor = if (field.getName() != propertyName) MyConvertedCodeProcessor() else null