Fixes #1398. Fix tests that use unreachable code after Never (#1402)

Authored by @sgrekhov.

Fix tests that use unreachable code after `Never`. Change testing members of Never.

LanguageFeatures/nnbd/expression_typing_A02_t01.dart

@@ -7,8 +7,8 @@
 /// type Never.
 ///
 /// @description Checks that calling a method (including an operator) or getter
-/// on a receiver of static type Never is treated by static analysis as producing
-/// a result of type Never
+/// on a receiver of static type [Never] is treated by static analysis as
+/// producing a result of type [Never] (except members of [Object])
 /// @issue 41273
 /// @author sgrekhov@unipro.ru
 
@@ -17,7 +17,13 @@
 void test(var x) {
   if (x is Never) {
     Never n1 = x.toString();
+//               ^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
     Never n2 = x.runtimeType;
+//               ^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
     Never n3 = x.someGetter;
     Never n4 = x.someMethod();
     Never n5 = x + x;

LanguageFeatures/nnbd/expression_typing_A03_t01.dart

@@ -2,11 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-/// @assertion Tearing off a method from a receiver of static type Never produces
-/// a value of type Never.
+/// @assertion Tearing off a method from a receiver of static type[ Never]
+/// produces a value of type [Never].
 ///
 /// @description Checks that tearing off a method from a receiver of static type
-/// Never produces a value of type Never.
+/// [Never] produces a value of type [Never] (except members of [Object]).
 /// @issue 41273
 /// @author sgrekhov@unipro.ru
 
@@ -15,6 +15,9 @@
 void test(var x) {
   if (x is Never) {
     Never n1 = x.toString;
+//             ^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
     Never n2 = x.someMethod;
   }
 }

LanguageFeatures/nnbd/static_errors_A17_t01.dart

@@ -13,14 +13,14 @@
 /// @issue 39866
 
 // Requirements=nnbd-strong
-void test(var x) {
-  if (x is Never) {
-    x.toString();
-    x.runtimeType;
-    x.s = 1;
-  }
-}
+
+Never foo() => throw Exception();
 
 main() {
-  test(null);
+  try {
+    foo().toString();
+    foo().runtimeType;
+    foo().x;
+    foo().s = 1;
+  } catch (_) {}
 }

LanguageFeatures/nnbd/static_errors_A17_t02.dart

@@ -7,22 +7,22 @@
 /// Implementations that provide feedback about dead or unreachable code are
 /// encouraged to indicate that any arguments to the invocation are unreachable.
 ///
-/// @description Check that it is an error to call a method, setter, or getter on
-/// a receiver of static type Never. Test type aliases
+/// @description Check that it is not an error to call a method, setter, or
+/// getter on a receiver of static type Never. Test type aliases
 /// @author sgrekhov@unipro.ru
 /// @issue 39866
 
 // Requirements=nnbd-strong
+
 typedef Neverland = Never;
 
-void test(var x) {
-  if (x is Neverland) {
-    x.toString();
-    x.runtimeType;
-    x.s = 1;
-  }
-}
+Neverland foo() => throw Exception();
 
 main() {
-  test(null);
+  try {
+    foo().toString();
+    foo().runtimeType;
+    foo().x;
+    foo().s = 1;
+  } catch (_) {}
 }

LanguageFeatures/nnbd/static_errors_A17_t03.dart

@@ -13,41 +13,41 @@
 /// @issue 39866
 
 // Requirements=nnbd-strong
-void test(var x) {
-  if (x is Never) {
-    x?.toString();
-//   ^^
+
+Never foo() => throw Exception();
+
+main() {
+  try {
+    foo()?.toString();
+//       ^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
-    x?.runtimeType;
-//   ^^
+    foo()?.runtimeType;
+//       ^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
-    x?.s = 1;
-//   ^^
+    foo()?.s = 1;
+//       ^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
-    x?..toString();
-//   ^^^
+    foo()?..toString();
+//       ^^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
-    x?..runtimeType;
-//   ^^^
+    foo()?..runtimeType;
+//       ^^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
-    x?..s = 1;
-//   ^^^
+    foo()?..s = 1;
+//       ^^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
-  }
-}
 
-main() {
-  test(null);
+  } catch (_) {}
 }

LanguageFeatures/nnbd/static_errors_A17_t04.dart

@@ -7,50 +7,53 @@
 /// Implementations that provide feedback about dead or unreachable code are
 /// encouraged to indicate that any arguments to the invocation are unreachable.
 ///
-/// @description Check that it is a warning to call a method, setter, or
+/// @description Check that it is not an error to call a method, setter, or
 /// getter on a receiver of static type Never via a null aware operator. Test
 /// type aliases
 /// @author sgrekhov@unipro.ru
 /// @issue 39866
 
 // Requirements=nnbd-strong
+
 typedef Neverland = Never;
 
-void test(var x) {
-  if (x is Neverland) {
-    x?.toString();
-//   ^^
+Neverland foo() => throw Exception();
+
+main() {
+  try {
+    foo()?.toString();
+//       ^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
-    x?.runtimeType;
-//   ^^
+    foo()?.runtimeType;
+//       ^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
-    x?.s = 1;
-//   ^^
+    foo()?.s = 1;
+//       ^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?.' has type 'Never' which excludes null.
-    x?..toString();
-//   ^^^
+    foo()
+      ?..toString();
+//       ^^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
-    x?..runtimeType;
-//   ^^^
+    foo()
+      ?..runtimeType;
+//       ^^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
-    x?..s = 1;
-//   ^^^
+    foo()
+      ?..s = 1;
+//       ^^^
 // [analyzer] STATIC_WARNING.INVALID_NULL_AWARE_OPERATOR
 //  ^
 // [cfe] Operand of null-aware operation '?..' has type 'Never' which excludes null.
-  }
-}
 
-main() {
-  test(null);
+  } catch (_) {}
 }

LanguageFeatures/nnbd/weak/expression_typing_A02_t01.dart

@@ -7,8 +7,8 @@
 /// type Never.
 ///
 /// @description Checks that calling a method (including an operator) or getter
-/// on a receiver of static type Never is treated by static analysis as producing
-/// a result of type Never
+/// on a receiver of static type [Never] is treated by static analysis as
+/// producing a result of type [Never] (except members of [Object]).
 /// @issue 41273
 /// @author sgrekhov@unipro.ru
 
@@ -17,7 +17,13 @@
 void test(var x) {
   if (x is Never) {
     Never n1 = x.toString();
+//               ^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
     Never n2 = x.runtimeType;
+//               ^^^^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
     Never n3 = x.someGetter;
     Never n4 = x.someMethod();
     Never n5 = x + x;

LanguageFeatures/nnbd/weak/expression_typing_A03_t01.dart

@@ -2,11 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-/// @assertion Tearing off a method from a receiver of static type Never produces
-/// a value of type Never.
+/// @assertion Tearing off a method from a receiver of static type [Never]
+/// produces a value of type [Never].
 ///
 /// @description Checks that tearing off a method from a receiver of static type
-/// Never produces a value of type Never.
+/// [Never] produces a value of type [Never] (except members of [Object]).
 /// @issue 41273
 /// @author sgrekhov@unipro.ru
 
@@ -15,6 +15,9 @@
 void test(var x) {
   if (x is Never) {
     Never n1 = x.toString;
+//               ^^^^^^^^
+// [analyzer] unspecified
+// [cfe] unspecified
     Never n2 = x.someMethod;
   }
 }

LanguageFeatures/nnbd/weak/static_errors_A17_t01.dart

@@ -8,19 +8,19 @@
 /// encouraged to indicate that any arguments to the invocation are unreachable.
 ///
 /// @description Check that it is not an error to call a method, setter, or
-/// getter on a receiver of static type Never.
+/// getter on a receiver of static type [Never].
 /// @author sgrekhov@unipro.ru
 /// @issue 39866
 
 // Requirements=nnbd-weak
-void test(var x) {
-  if (x is Never) {
-    x.toString();
-    x.runtimeType;
-    x.s = 1;
-  }
-}
+
+Never foo() => throw Exception();
 
 main() {
-  test(null);
+  try {
+    foo().toString();
+    foo().runtimeType;
+    foo().x;
+    foo().s = 1;
+  } catch (_) {}
 }

LanguageFeatures/nnbd/weak/static_errors_A17_t02.dart

@@ -7,22 +7,22 @@
 /// Implementations that provide feedback about dead or unreachable code are
 /// encouraged to indicate that any arguments to the invocation are unreachable.
 ///
-/// @description Check that it is an error to call a method, setter, or getter on
-/// a receiver of static type Never. Test type aliases
+/// @description Check that it is not an error to call a method, setter, or
+/// getter on a receiver of static type [Never]. Test type aliases
 /// @author sgrekhov@unipro.ru
 /// @issue 39866
 
 // Requirements=nnbd-weak
+
 typedef Neverland = Never;
 
-void test(var x) {
-  if (x is Neverland) {
-    x.toString();
-    x.runtimeType;
-    x.s = 1;
-  }
-}
+Neverland foo() => throw Exception();
 
 main() {
-  test(null);
+  try {
+    foo().toString();
+    foo().runtimeType;
+    foo().x;
+    foo().s = 1;
+  } catch (_) {}
 }