[ddc] cleanup: use Never direclty in nnbd tests

Change-Id: I67aceaccb819ad6033bdb9c7d9870b05859c1064
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/138900
Reviewed-by: Nicholas Shahan <nshahan@google.com>

sdk_nnbd/lib/_internal/js_dev_runtime/private/ddc_runtime/types.dart

@@ -410,7 +410,7 @@ class NeverType extends DartType {
 }
 
 @JSExportName('Never')
-final never_ = NeverType();
+final _never = NeverType();
 
 @JSExportName('dynamic')
 final _dynamic = DynamicType();
@@ -432,7 +432,7 @@ class VoidType extends DartType {
 @JSExportName('void')
 final void_ = VoidType();
 
-// TODO(nshahan): Cleanup and consolidate NeverType, BottomType, bottom, never_.
+// TODO(nshahan): Cleanup and consolidate NeverType, BottomType, bottom, _never.
 class BottomType extends DartType {
   toString() => 'bottom';
 }

tests/compiler/dartdevc_native/nnbd_strong_subtype_test.dart

@@ -38,29 +38,29 @@ void main() {
 
   // Bottom is subtype of top.
   // never <: dynamic
-  checkProperSubtype(neverType, dynamic);
+  checkProperSubtype(Never, dynamic);
   // never <: void
-  checkProperSubtype(neverType, voidType);
+  checkProperSubtype(Never, voidType);
   // never <: Object?
-  checkProperSubtype(neverType, nullable(Object));
+  checkProperSubtype(Never, nullable(Object));
 
   // Object is between top and bottom.
   // Object <: Object?
   checkProperSubtype(Object, nullable(Object));
   // never <: Object
-  checkProperSubtype(neverType, Object);
+  checkProperSubtype(Never, Object);
 
   // Null is between top and bottom.
   // Null <: Object?
   checkProperSubtype(Null, nullable(Object));
   // never <: Null
-  checkProperSubtype(neverType, Null);
+  checkProperSubtype(Never, Null);
 
   // Class is between Object and bottom.
   // A <: Object
   checkProperSubtype(A, dynamic);
   // never <: A
-  checkProperSubtype(neverType, A);
+  checkProperSubtype(Never, A);
 
   // Nullable types are a union of T and Null.
   // A <: A?
@@ -83,7 +83,7 @@ void main() {
   // Null <: Object*
   checkSubtype(Null, legacy(Object));
   // never <: Object*
-  checkSubtype(neverType, legacy(Object));
+  checkSubtype(Never, legacy(Object));
   // A* <: A
   checkSubtype(legacy(A), A);
   // A <: A*
@@ -99,7 +99,7 @@ void main() {
   // Null <: A*
   checkProperSubtype(Null, legacy(A));
   // never <: A*
-  checkProperSubtype(neverType, legacy(A));
+  checkProperSubtype(Never, legacy(A));
 
   // Futures.
   // Null <: FutureOr<Object?>
@@ -122,7 +122,7 @@ void main() {
   checkProperSubtype(
       generic1(Future, nullable(Object)), futureOrOf(nullable(Object)));
   // FutureOr<Never> <: Future<Never>
-  checkSubtype(futureOrOf(neverType), generic1(Future, neverType));
+  checkSubtype(futureOrOf(Never), generic1(Future, Never));
   // Future<B> <: FutureOr<A>
   checkProperSubtype(generic1(Future, B), futureOrOf(A));
   // B <: <: FutureOr<A>
@@ -271,7 +271,7 @@ void main() {
   // A? <\: A
   checkSubtypeFailure(nullable(A), A);
   // Null <\: never
-  checkSubtypeFailure(Null, neverType);
+  checkSubtypeFailure(Null, Never);
   // Null <\: Object
   checkSubtypeFailure(Null, Object);
   // Null <\: A

tests/compiler/dartdevc_native/nnbd_type_normalization_test.dart

@@ -24,7 +24,7 @@ void main() {
   // Null? == Null
   Expect.identical(nullable(Null), Null);
   // Never? == Null
-  Expect.identical(nullable(dart.wrapType(dart.never_)), Null);
+  Expect.identical(nullable(Never), Null);
   // dynamic? == dynamic
   Expect.identical(nullable(dynamic), dynamic);
   // void? == void

tests/compiler/dartdevc_native/nnbd_weak_subtype_test.dart

@@ -38,29 +38,29 @@ void main() {
 
   // Bottom is subtype of top.
   // never <: dynamic
-  checkProperSubtype(neverType, dynamic);
+  checkProperSubtype(Never, dynamic);
   // never <: void
-  checkProperSubtype(neverType, voidType);
+  checkProperSubtype(Never, voidType);
   // never <: Object?
-  checkProperSubtype(neverType, nullable(Object));
+  checkProperSubtype(Never, nullable(Object));
 
   // Object is between top and bottom.
   // Object <: Object?
   checkSubtype(Object, nullable(Object));
   // never <: Object
-  checkProperSubtype(neverType, Object);
+  checkProperSubtype(Never, Object);
 
   // Null is between top and bottom.
   // Null <: Object?
   checkProperSubtype(Null, nullable(Object));
   // never <: Null
-  checkSubtype(neverType, Null);
+  checkSubtype(Never, Null);
 
   // Class is between Object and bottom.
   // A <: Object
   checkProperSubtype(A, dynamic);
   // never <: A
-  checkProperSubtype(neverType, A);
+  checkProperSubtype(Never, A);
 
   // Nullable types are a union of T and Null.
   // A <: A?
@@ -83,7 +83,7 @@ void main() {
   // Null <: Object*
   checkSubtype(Null, legacy(Object));
   // never <: Object*
-  checkSubtype(neverType, legacy(Object));
+  checkSubtype(Never, legacy(Object));
   // A* <: A
   checkSubtype(legacy(A), A);
   // A <: A*
@@ -99,7 +99,7 @@ void main() {
   // Null <: A*
   checkProperSubtype(Null, legacy(A));
   // never <: A*
-  checkProperSubtype(neverType, legacy(A));
+  checkProperSubtype(Never, legacy(A));
 
   // Futures.
   // Null <: FutureOr<Object?>
@@ -122,7 +122,7 @@ void main() {
   checkProperSubtype(
       generic1(Future, nullable(Object)), futureOrOf(nullable(Object)));
   // FutureOr<Never> <: Future<Never>
-  checkSubtype(futureOrOf(neverType), generic1(Future, neverType));
+  checkSubtype(futureOrOf(Never), generic1(Future, Never));
   // Future<B> <: FutureOr<A>
   checkProperSubtype(generic1(Future, B), futureOrOf(A));
   // B <: <: FutureOr<A>
@@ -271,7 +271,7 @@ void main() {
   // A? <: A
   checkSubtype(nullable(A), A);
   // Null <: never
-  checkSubtype(Null, neverType);
+  checkSubtype(Null, Never);
   // Null <: Object
   checkProperSubtype(Null, Object);
   // Null <: A

tests/compiler/dartdevc_native/runtime_utils_nnbd.dart

@@ -7,9 +7,6 @@ import 'dart:_runtime' as dart;
 
 import 'package:expect/expect.dart';
 
-/// The runtime representation of the never type.
-final neverType = dart.wrapType(dart.never_);
-
 /// Unwrap the user code type representation to expose the runtime
 /// representation of [t].
 ///