analyze incomplete 'in' expression

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

@@ -1075,9 +1075,12 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
             @Nullable JetExpression right,
             @NotNull ExpressionTypingContext context
     ) {
-        if (right == null) return JetTypeInfo.create(null, context.dataFlowInfo);
-
         ExpressionTypingContext contextWithNoExpectedType = context.replaceExpectedType(NO_EXPECTED_TYPE);
+        if (right == null) {
+            if (left != null) facade.getTypeInfo(left, contextWithNoExpectedType);
+            return JetTypeInfo.create(null, context.dataFlowInfo);
+        }
+
         DataFlowInfo dataFlowInfo = facade.getTypeInfo(right, contextWithNoExpectedType).getDataFlowInfo();
 
         ExpressionReceiver receiver = safeGetExpressionReceiver(facade, right, contextWithNoExpectedType);

compiler/testData/diagnostics/tests/incompleteCode/inExpr.kt

@@ -0,0 +1,5 @@
+package l
+
+fun test(a: Int) {
+    if (a in<!SYNTAX!><!> ) {} //a is not unresolved
+}

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

@@ -2582,6 +2582,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/incompleteCode/checkNothingIsSubtype.kt");
             }
             
+            @TestMetadata("inExpr.kt")
+            public void testInExpr() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/incompleteCode/inExpr.kt");
+            }
+            
             @TestMetadata("incompleteAssignment.kt")
             public void testIncompleteAssignment() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/incompleteCode/incompleteAssignment.kt");