From 9939f96c090eb40f87435e188abaf9d5b536bfec Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <Mikhail.Glukhikh@jetbrains.com>
Date: Wed, 16 Sep 2015 12:05:44 +0300
Subject: [PATCH] "field" reassignment: fix and test

---
 .../jetbrains/kotlin/cfg/JetFlowInformationProvider.java  | 8 ++++++--
 .../diagnostics/tests/backingField/FieldReassignment.kt   | 5 +++++
 .../diagnostics/tests/backingField/FieldReassignment.txt  | 3 +++
 .../kotlin/checkers/JetDiagnosticsTestGenerated.java      | 6 ++++++
 4 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 compiler/testData/diagnostics/tests/backingField/FieldReassignment.kt
 create mode 100644 compiler/testData/diagnostics/tests/backingField/FieldReassignment.txt

diff --git a/compiler/frontend/src/org/jetbrains/kotlin/cfg/JetFlowInformationProvider.java b/compiler/frontend/src/org/jetbrains/kotlin/cfg/JetFlowInformationProvider.java
index 5e2f5631e37..3973f48fc88 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/cfg/JetFlowInformationProvider.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/cfg/JetFlowInformationProvider.java
@@ -47,6 +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.diagnostics.Diagnostic;
 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory;
 import org.jetbrains.kotlin.diagnostics.Errors;
@@ -400,8 +401,11 @@ public class JetFlowInformationProvider {
             @NotNull Collection<VariableDescriptor> varWithValReassignErrorGenerated
     ) {
         VariableDescriptor variableDescriptor = ctxt.variableDescriptor;
-        if (JetPsiUtil.isBackingFieldReference(expression) && variableDescriptor instanceof PropertyDescriptor) {
-            PropertyDescriptor propertyDescriptor = (PropertyDescriptor) variableDescriptor;
+        if (variableDescriptor instanceof SyntheticFieldDescriptor
+            || (JetPsiUtil.isBackingFieldReference(expression) && variableDescriptor instanceof PropertyDescriptor)) {
+            PropertyDescriptor propertyDescriptor = variableDescriptor instanceof SyntheticFieldDescriptor
+                                                    ? ((SyntheticFieldDescriptor) variableDescriptor).getPropertyDescriptor()
+                                                    : (PropertyDescriptor) variableDescriptor;
             JetPropertyAccessor accessor = PsiTreeUtil.getParentOfType(expression, JetPropertyAccessor.class);
             if (accessor != null) {
                 DeclarationDescriptor accessorDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, accessor);
diff --git a/compiler/testData/diagnostics/tests/backingField/FieldReassignment.kt b/compiler/testData/diagnostics/tests/backingField/FieldReassignment.kt
new file mode 100644
index 00000000000..755979ab00d
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/backingField/FieldReassignment.kt
@@ -0,0 +1,5 @@
+val my: Int = 1
+    get() {
+        field++
+        return field
+    }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/backingField/FieldReassignment.txt b/compiler/testData/diagnostics/tests/backingField/FieldReassignment.txt
new file mode 100644
index 00000000000..4d7f9aba66a
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/backingField/FieldReassignment.txt
@@ -0,0 +1,3 @@
+package
+
+public val my: kotlin.Int = 1
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
index 21c27cef42c..cf34c914f3f 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
@@ -1362,6 +1362,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("FieldReassignment.kt")
+            public void testFieldReassignment() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldReassignment.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("FieldShadow.kt")
             public void testFieldShadow() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/backingField/FieldShadow.kt");