Descriptors with error types can override each other

compiler/frontend/src/org/jetbrains/jet/lang/resolve/OverridingUtil.java

@@ -185,7 +185,8 @@ public class OverridingUtil {
                 JetType superValueParameter = superValueParameters.get(i);
                 JetType subValueParameter = subValueParameters.get(i);
 
-                if (!JetTypeChecker.INSTANCE.equalTypes(superValueParameter, subValueParameter, axioms)) {
+                boolean bothErrors = ErrorUtils.isErrorType(superValueParameter) && ErrorUtils.isErrorType(subValueParameter);
+                if (!bothErrors && !JetTypeChecker.INSTANCE.equalTypes(superValueParameter, subValueParameter, axioms)) {
                     return OverrideCompatibilityInfo.valueParameterTypeMismatch(superValueParameter, subValueParameter, OverrideCompatibilityInfo.Result.INCOMPATIBLE);
                 }
             }

compiler/testData/lazyResolve/namespaceComparator/OverrideWithErrors.kt

@@ -0,0 +1,9 @@
+package test
+
+open class A {
+  open fun foo(a: E) {}
+}
+
+class B : A() {
+  override fun foo(a: E) {}
+}

compiler/testData/lazyResolve/namespaceComparator/OverrideWithErrors.txt

@@ -0,0 +1,10 @@
+namespace test
+
+internal open class test.A : jet.Any {
+    public final /*constructor*/ fun <init>(): test.A
+    internal open fun foo(/*0*/ a: [ERROR : E]): jet.Tuple0
+}
+internal final class test.B : test.A {
+    public final /*constructor*/ fun <init>(): test.B
+    internal open override /*1*/ fun foo(/*0*/ a: [ERROR : E]): jet.Tuple0
+}

compiler/tests/org/jetbrains/jet/lang/resolve/lazy/LazyResolveNamespaceComparingTestGenerated.java

@@ -1287,6 +1287,11 @@ public class LazyResolveNamespaceComparingTestGenerated extends AbstractLazyReso
             doTestSinglePackage("compiler/testData/lazyResolve/namespaceComparator/innerObject.kt");
         }
         
+        @TestMetadata("OverrideWithErrors.kt")
+        public void testOverrideWithErrors() throws Exception {
+            doTestSinglePackage("compiler/testData/lazyResolve/namespaceComparator/OverrideWithErrors.kt");
+        }
+        
         @TestMetadata("packageLevelObject.kt")
         public void testPackageLevelObject() throws Exception {
             doTestSinglePackage("compiler/testData/lazyResolve/namespaceComparator/packageLevelObject.kt");