no report 'UNNECESSARY_NOT_NULL_ASSERTION' on error types

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

@@ -885,7 +885,7 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
             return typeInfo;
         }
         DataFlowInfo dataFlowInfo = typeInfo.getDataFlowInfo();
-        if (isKnownToBeNotNull(baseExpression, context)) {
+        if (isKnownToBeNotNull(baseExpression, context) && !ErrorUtils.isErrorType(type)) {
             context.trace.report(UNNECESSARY_NOT_NULL_ASSERTION.on(operationSign, type));
         }
         else {

compiler/testData/diagnostics/tests/nullabilityAndAutoCasts/noUnnecessaryNotNullAssertionOnErrorType.kt

@@ -0,0 +1,7 @@
+package a
+
+fun foo() {
+    bar()!!
+}
+
+fun bar() = <!UNRESOLVED_REFERENCE!>aa<!>

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

@@ -2098,6 +2098,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/nullabilityAndAutoCasts/kt362.kt");
             }
             
+            @TestMetadata("noUnnecessaryNotNullAssertionOnErrorType.kt")
+            public void testNoUnnecessaryNotNullAssertionOnErrorType() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/nullabilityAndAutoCasts/noUnnecessaryNotNullAssertionOnErrorType.kt");
+            }
+            
             @TestMetadata("NullableNothingIsExactlyNull.kt")
             public void testNullableNothingIsExactlyNull() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/nullabilityAndAutoCasts/NullableNothingIsExactlyNull.kt");