Smart casts to nothing after comparison with null

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.java

@@ -219,11 +219,11 @@ import static org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability.NOT_NULL
         newTypeInfo.putAll(a, collectTypesFromMeAndParents(b));
         newTypeInfo.putAll(b, collectTypesFromMeAndParents(a));
         if (!a.getType().equals(b.getType())) {
-            // To avoid smart casts to Nothing or Nothing? and recording base types of own type
-            if (!KotlinBuiltIns.isNothingOrNullableNothing(b.getType()) && !TypeUtilsKt.isSubtypeOf(a.getType(), b.getType())) {
+            // To avoid recording base types of own type
+            if (!TypeUtilsKt.isSubtypeOf(a.getType(), b.getType())) {
                 newTypeInfo.put(a, b.getType());
             }
-            if (!KotlinBuiltIns.isNothingOrNullableNothing(a.getType()) && !TypeUtilsKt.isSubtypeOf(b.getType(), a.getType())) {
+            if (!TypeUtilsKt.isSubtypeOf(b.getType(), a.getType())) {
                 newTypeInfo.put(b, a.getType());
             }
         }

compiler/testData/diagnostics/tests/dataFlowInfoTraversal/ExclExcl.kt

@@ -3,19 +3,19 @@ fun bar(x: Int) = x + 1
 fun f1(x: Int?) {
     bar(<!TYPE_MISMATCH!>x<!>)
     if (x != null) bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>)
-    if (x == null) bar(x!!)
+    if (x == null) <!UNREACHABLE_CODE!>bar(<!><!DEBUG_INFO_SMARTCAST!>x<!>!!<!UNREACHABLE_CODE!>)<!>
 }
 
 fun f2(x: Int?) {    
-    if (x != null) else bar(x!!)
+    if (x != null) else <!DEBUG_INFO_SMARTCAST!>x<!>!!
 }
 
 fun f3(x: Int?) {    
-    if (x != null) bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) else bar(x!!)
+    if (x != null) bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) else <!DEBUG_INFO_SMARTCAST!>x<!>!!
 }
     
 fun f4(x: Int?) {    
-    if (x == null) bar(x!!) else bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>)
+    if (x == null) <!DEBUG_INFO_SMARTCAST!>x<!>!! else bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>)
 }
 
 fun f5(x: Int?) {    

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/kt2164.kt

@@ -22,8 +22,8 @@ fun main(args : Array<String>) {
         foo(<!DEBUG_INFO_SMARTCAST!>x<!>)
     } else {
         foo(<!TYPE_MISMATCH!>x<!>)
-        foo(x!!)
-        foo(<!DEBUG_INFO_SMARTCAST!>x<!>)
+        <!UNREACHABLE_CODE!>foo(<!><!DEBUG_INFO_SMARTCAST!>x<!>!!<!UNREACHABLE_CODE!>)<!>
+        <!UNREACHABLE_CODE!>foo(<!DEBUG_INFO_SMARTCAST!>x<!>)<!>
     }
 
     foo(<!DEBUG_INFO_SMARTCAST!>x<!>)

compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt

@@ -2,13 +2,13 @@ fun <T> test(t: T): T {
     if (t != null) {
         return t<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
     }
-    return t!!
+    return <!DEBUG_INFO_SMARTCAST!>t<!>!!
 }
 
 fun <T> T.testThis(): String {
     if (this != null) {
         return this<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.toString()
     }
-    return this!!.toString()
+    return <!DEBUG_INFO_SMARTCAST!>this<!>!!.toString()
 }
 

compiler/testData/diagnostics/tests/smartCasts/notNullorNotNull.kt

@@ -0,0 +1,6 @@
+fun bar(x: Int?): Int {
+    if (x != null) return -1
+    if (<!SENSELESS_COMPARISON!>x == null<!>) return -2
+    // Should be unreachable
+    return 2 + 2
+}

compiler/testData/diagnostics/tests/smartCasts/notNullorNotNull.txt

@@ -0,0 +1,3 @@
+package
+
+public fun bar(/*0*/ x: kotlin.Int?): kotlin.Int

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -14625,6 +14625,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("notNullorNotNull.kt")
+            public void testNotNullorNotNull() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/notNullorNotNull.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("ownerDeclaresBothModifies.kt")
             public void testOwnerDeclaresBothModifies() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/ownerDeclaresBothModifies.kt");