EA-35501 fixed (checkBackingField assert)

compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetFlowInformationProvider.java

@@ -367,7 +367,8 @@ public class JetFlowInformationProvider {
 
         JetNamedDeclaration parentDeclaration = PsiTreeUtil.getParentOfType(element, JetNamedDeclaration.class);
         DeclarationDescriptor declarationDescriptor = trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, parentDeclaration);
-        assert declarationDescriptor != null;
+        if (declarationDescriptor == null) return false;
+
         DeclarationDescriptor containingDeclaration = variableDescriptor.getContainingDeclaration();
         if ((containingDeclaration instanceof ClassDescriptor) && DescriptorUtils.isAncestor(containingDeclaration, declarationDescriptor, false)) {
             return false;

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/checkBackingFieldException.jet

@@ -0,0 +1,17 @@
+package h
+
+class Square() {
+  var size : Double =
+  <!UNRESOLVED_REFERENCE!>set<!>(<!UNRESOLVED_REFERENCE!>value<!>) {
+    $area = size * size
+  }
+
+  <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>var area : Double<!>
+  private set
+}
+
+fun main(args : Array<String>) {
+  val s = Square()
+
+  s.size = 2.0
+}