"field": refactoring, isBackingFieldReference, referencedProperty

compiler/frontend/src/org/jetbrains/kotlin/cfg/JetFlowInformationProvider.java

@@ -47,7 +47,7 @@ import org.jetbrains.kotlin.cfg.pseudocodeTraverser.Edges;
 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.PseudocodeTraverserPackage;
 import org.jetbrains.kotlin.cfg.pseudocodeTraverser.TraversalOrder;
 import org.jetbrains.kotlin.descriptors.*;
-import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor;
+import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptorKt;
 import org.jetbrains.kotlin.diagnostics.Diagnostic;
 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
 import org.jetbrains.kotlin.diagnostics.Errors;
@@ -401,11 +401,8 @@ public class JetFlowInformationProvider {
             @NotNull Collection<VariableDescriptor> varWithValReassignErrorGenerated
     ) {
         VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
-        if (variableDescriptor instanceof SyntheticFieldDescriptor
-            || (JetPsiUtil.isBackingFieldReference(expression) && variableDescriptor instanceof PropertyDescriptor)) {
-            PropertyDescriptor propertyDescriptor = variableDescriptor instanceof SyntheticFieldDescriptor
-                                                    ? ((SyntheticFieldDescriptor) variableDescriptor).getPropertyDescriptor()
-                                                    : (PropertyDescriptor) variableDescriptor;
+        PropertyDescriptor propertyDescriptor = SyntheticFieldDescriptorKt.getReferencedProperty(variableDescriptor);
+        if (JetPsiUtil.isBackingFieldReference(expression, variableDescriptor) && propertyDescriptor != null) {
             JetPropertyAccessor accessor = PsiTreeUtil.getParentOfType(expression, JetPropertyAccessor.class);
             if (accessor != null) {
                 DeclarationDescriptor accessorDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, accessor);
@@ -573,7 +570,7 @@ public class JetFlowInformationProvider {
             boolean reportError
     ) {
         error[0] = false;
-        if (JetPsiUtil.isBackingFieldReference(element)) {
+        if (JetPsiUtil.isBackingFieldReference(element, null)) {
             return true;
         }
         if (element instanceof JetDotQualifiedExpression && isCorrectBackingFieldReference(

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

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.descriptors.impl
 
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyAccessorDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.descriptors.annotations.Annotations
@@ -38,4 +39,7 @@ class SyntheticFieldDescriptor private constructor(
     companion object {
         val NAME = Name.identifier("field")
     }
-}
+}
+
+public val DeclarationDescriptor.referencedProperty: PropertyDescriptor?
+    get() = if (this is SyntheticFieldDescriptor) this.propertyDescriptor else if (this is PropertyDescriptor) this else null

compiler/frontend/src/org/jetbrains/kotlin/psi/JetPsiUtil.java

@@ -33,6 +33,8 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.JetNodeTypes;
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
+import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor;
 import org.jetbrains.kotlin.kdoc.psi.api.KDocElement;
 import org.jetbrains.kotlin.lexer.JetToken;
 import org.jetbrains.kotlin.lexer.JetTokens;
@@ -407,12 +409,12 @@ public class JetPsiUtil {
         return declaration.getBodyExpression() == null;
     }
 
-    public static boolean isBackingFieldReference(@NotNull JetSimpleNameExpression expression) {
-        return expression.getReferencedNameElementType() == JetTokens.FIELD_IDENTIFIER;
+    public static boolean isBackingFieldReference(@NotNull JetSimpleNameExpression expression, @Nullable DeclarationDescriptor descriptor) {
+        return descriptor instanceof SyntheticFieldDescriptor || expression.getReferencedNameElementType() == JetTokens.FIELD_IDENTIFIER;
     }
 
-    public static boolean isBackingFieldReference(@Nullable JetElement element) {
-        return element instanceof JetSimpleNameExpression && isBackingFieldReference((JetSimpleNameExpression)element);
+    public static boolean isBackingFieldReference(@Nullable JetElement element, @Nullable DeclarationDescriptor descriptor) {
+        return element instanceof JetSimpleNameExpression && isBackingFieldReference((JetSimpleNameExpression) element, descriptor);
     }
 
     @Nullable

js/js.translator/src/org/jetbrains/kotlin/js/translate/reference/BackingFieldAccessTranslator.java

@@ -18,9 +18,8 @@ package org.jetbrains.kotlin.js.translate.reference;
 
 import com.google.dart.compiler.backend.js.ast.JsExpression;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor;
-import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptor;
+import org.jetbrains.kotlin.descriptors.impl.SyntheticFieldDescriptorKt;
 import org.jetbrains.kotlin.js.translate.context.TemporaryVariable;
 import org.jetbrains.kotlin.js.translate.context.TranslationContext;
 import org.jetbrains.kotlin.js.translate.general.AbstractTranslator;
@@ -41,12 +40,11 @@ public final class BackingFieldAccessTranslator extends AbstractTranslator imple
     /*package*/
     public static BackingFieldAccessTranslator newInstance(@NotNull JetSimpleNameExpression expression,
                                                     @NotNull TranslationContext context) {
-        DeclarationDescriptor referencedProperty = getDescriptorForReferenceExpression(context.bindingContext(), expression);
-        if (referencedProperty instanceof SyntheticFieldDescriptor) {
-            referencedProperty = ((SyntheticFieldDescriptor) referencedProperty).getPropertyDescriptor();
-        }
-        assert referencedProperty instanceof PropertyDescriptor;
-        return new BackingFieldAccessTranslator((PropertyDescriptor) referencedProperty, context);
+        PropertyDescriptor referencedProperty = SyntheticFieldDescriptorKt.getReferencedProperty(
+                getDescriptorForReferenceExpression(context.bindingContext(), expression)
+        );
+        assert referencedProperty != null;
+        return new BackingFieldAccessTranslator(referencedProperty, context);
     }
 
     private BackingFieldAccessTranslator(@NotNull PropertyDescriptor descriptor, @NotNull TranslationContext context) {

js/js.translator/src/org/jetbrains/kotlin/js/translate/reference/ReferenceTranslator.java

@@ -104,8 +104,7 @@ public final class ReferenceTranslator {
     public static AccessTranslator getAccessTranslator(@NotNull JetSimpleNameExpression referenceExpression,
             @Nullable JsExpression receiver,
             @NotNull TranslationContext context) {
-        if (getDescriptorForReferenceExpression(context.bindingContext(), referenceExpression) instanceof SyntheticFieldDescriptor
-            || isBackingFieldReference(referenceExpression)) {
+        if (isBackingFieldReference(referenceExpression, getDescriptorForReferenceExpression(context.bindingContext(), referenceExpression))) {
             return BackingFieldAccessTranslator.newInstance(referenceExpression, context);
         }
         if (canBePropertyAccess(referenceExpression, context)) {