incomplete assignment bug from EA fixed

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingVisitorForStatements.java

@@ -169,6 +169,9 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
     }
 
     protected JetType visitAssignmentOperation(JetBinaryExpression expression, ExpressionTypingContext contextWithExpectedType) {
+        JetExpression right = expression.getRight();
+        if (right == null) return null;
+
         //There is a temporary binding trace for an opportunity to resolve set method for array if needed (the initial trace should be used there)
         TemporaryBindingTrace temporaryBindingTrace = TemporaryBindingTrace.create(contextWithExpectedType.trace);
         ExpressionTypingContext context = contextWithExpectedType.replaceExpectedType(TypeUtils.NO_EXPECTED_TYPE).replaceExpectedReturnType(TypeUtils.NO_EXPECTED_TYPE).replaceBindingTrace(temporaryBindingTrace);
@@ -180,7 +183,7 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
 
         JetType leftType = facade.getType(left, context);
         if (leftType == null) {
-            facade.getType(expression.getRight(), context);
+            facade.getType(right, context);
             context.trace.report(UNRESOLVED_REFERENCE.on(operationSign));
             temporaryBindingTrace.commit();
             return null;
@@ -208,7 +211,7 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
             for (ResolvedCall<? extends FunctionDescriptor> call : ambiguityResolutionResults.getResultingCalls()) {
                 descriptors.add(call.getResultingDescriptor());
             }
-            facade.getType(expression.getRight(), context);
+            facade.getType(right, context);
             context.trace.record(AMBIGUOUS_REFERENCE_TARGET, operationSign, descriptors);
         }
         else if (assignmentOperationType != null) {
@@ -222,7 +225,7 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
             context.trace.record(VARIABLE_REASSIGNMENT, expression);
             if (left instanceof JetArrayAccessExpression) {
                 ExpressionTypingContext contextForResolve = context.replaceScope(scope).replaceBindingTrace(TemporaryBindingTrace.create(contextWithExpectedType.trace));
-                basic.resolveArrayAccessSetMethod((JetArrayAccessExpression) left, expression.getRight(), contextForResolve, context.trace);
+                basic.resolveArrayAccessSetMethod((JetArrayAccessExpression) left, right, contextForResolve, context.trace);
             }
         }
         basic.checkLValue(context.trace, expression.getLeft());

compiler/testData/diagnostics/tests/incompleteCode/incompleteAssignment.jet

+package sum
+
+import java.util.*
+fun sum(a : IntArray) : Int {
+    // Write your solution here
+    <!UNRESOLVED_REFERENCE!>res<!> = 0
+    for (e in a)
+        res +=<!SYNTAX!><!>
+<!NO_RETURN_IN_FUNCTION_WITH_BLOCK_BODY!>}<!>
+fun main(args : Array<String>) {
+    test(0)
+    test(1, 1)
+    test(-1, -1, 0)
+    test(6, 1, 2, 3)
+    test(6, 1, 1, 1, 1, 1, 1)
+}
+// HELPER FUNCTIONS
+fun test(expectedSum : Int, vararg data : Int) {
+    val actualSum = sum(data)
+    assertEquals(actualSum, expectedSum, "\ndata = ${Arrays.toString(data)}\n" +
+    "sum(data) = ${actualSum}, but must be $expectedSum ")
+}
+fun assertEquals<T>(actual : T?, expected : T?, message : Any? = null) {
+    if (actual != expected) {
+        if (message == null)
+            throw AssertionError()
+        else
+            throw AssertionError(message)
+    }
+}