No smart casts to Nothing?

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

@@ -22,6 +22,7 @@ import kotlin.CollectionsKt;
 import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor;
 import org.jetbrains.kotlin.psi.KtExpression;
 import org.jetbrains.kotlin.resolve.BindingContext;
@@ -153,6 +154,7 @@ public class SmartCastManager {
             @NotNull DataFlowValue dataFlowValue,
             boolean recordExpressionType
     ) {
+        if (KotlinBuiltIns.isNullableNothing(type)) return;
         if (dataFlowValue.isPredictable()) {
             trace.record(SMARTCAST, expression, type);
             if (recordExpressionType) {

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) <!UNREACHABLE_CODE!>bar(<!><!ALWAYS_NULL, DEBUG_INFO_SMARTCAST!>x<!>!!<!UNREACHABLE_CODE!>)<!>
+    if (x == null) <!UNREACHABLE_CODE!>bar(<!><!ALWAYS_NULL!>x<!>!!<!UNREACHABLE_CODE!>)<!>
 }
 
 fun f2(x: Int?) {    
-    if (x != null) else <!ALWAYS_NULL, DEBUG_INFO_SMARTCAST!>x<!>!!
+    if (x != null) else <!ALWAYS_NULL!>x<!>!!
 }
 
 fun f3(x: Int?) {    
-    if (x != null) bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) else <!ALWAYS_NULL, DEBUG_INFO_SMARTCAST!>x<!>!!
+    if (x != null) bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) else <!ALWAYS_NULL!>x<!>!!
 }
     
 fun f4(x: Int?) {    
-    if (x == null) <!ALWAYS_NULL, DEBUG_INFO_SMARTCAST!>x<!>!! else bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>)
+    if (x == null) <!ALWAYS_NULL!>x<!>!! else bar(x<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>)
 }
 
 fun f5(x: Int?) {    

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

@@ -22,7 +22,7 @@ fun main(args : Array<String>) {
         foo(<!DEBUG_INFO_SMARTCAST!>x<!>)
     } else {
         foo(<!ALWAYS_NULL, TYPE_MISMATCH!>x<!>)
-        <!UNREACHABLE_CODE!>foo(<!><!ALWAYS_NULL, DEBUG_INFO_SMARTCAST!>x<!>!!<!UNREACHABLE_CODE!>)<!>
+        <!UNREACHABLE_CODE!>foo(<!><!ALWAYS_NULL!>x<!>!!<!UNREACHABLE_CODE!>)<!>
         <!UNREACHABLE_CODE!>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 <!ALWAYS_NULL, DEBUG_INFO_SMARTCAST!>t<!>!!
+    return <!ALWAYS_NULL!>t<!>!!
 }
 
 fun <T> T.testThis(): String {
     if (this != null) {
         return this<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.toString()
     }
-    return <!DEBUG_INFO_SMARTCAST!>this<!>!!.toString()
+    return this!!.toString()
 }
 

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

@@ -6,6 +6,6 @@ fun foo(): String {
     var t: String? = "y"
     if (t == null) t = "x"
     var x: Int? = null
-    if (x == null) <!TYPE_MISMATCH!><!DEBUG_INFO_SMARTCAST!>x<!> += null<!>
+    if (x == null) <!TYPE_MISMATCH!>x += null<!>
     return <!DEBUG_INFO_SMARTCAST!>t<!> + s
 }