Migrate "a" directory language tests off @compile-error.

The "@compile-error" comment is an old not-great way of defining static
error tests.

See: https://github.com/dart-lang/sdk/issues/45634
Change-Id: I35d4a7c7ad09cb77ff379af036180794d8b6afbf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/296403
Auto-Submit: Bob Nystrom <rnystrom@google.com>
Reviewed-by: Jake Macdonald <jakemac@google.com>
Commit-Queue: Bob Nystrom <rnystrom@google.com>

tests/language/abstract/beats_arguments_test.dart

@@ -12,5 +12,8 @@ abstract class A {
 }
 
 void main() {
-  /*@compile-error=unspecified*/ new A();
+  new A();
+  //  ^
+  // [analyzer] COMPILE_TIME_ERROR.INSTANTIATE_ABSTRACT_CLASS
+  // [cfe] The class 'A' is abstract and can't be instantiated.
 }

tests/language/abstract/override_adds_optional_args_concrete_subclass_test.dart

@@ -14,7 +14,11 @@ abstract class B extends A {
   void foo([x]);
 }
 
-class /*@compile-error=unspecified*/ C extends B {
+class C extends B {
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_IMPLEMENTATION_OVERRIDE
+// [cfe] The implementation of 'foo' in the non-abstract class 'C' does not conform to its interface.
+
   // However, there is a problem here because this class is concrete and doesn't
   // override foo.
 }

tests/language/abstract/override_adds_optional_args_concrete_test.dart

@@ -7,9 +7,13 @@ class A {
 }
 
 class B extends A {
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_IMPLEMENTATION_OVERRIDE
+// [cfe] The implementation of 'foo' in the non-abstract class 'B' does not conform to its interface.
+
   // This class declaration violates soundness, since it allows `new
   // B().foo(42)`, which would lead to invalid arguments being passed to A.foo.
-  void /*@compile-error=unspecified*/ foo([x]);
+  void foo([x]);
 }
 
 void f(B b) {

tests/language/abstract/override_adds_optional_args_supercall_test.dart

@@ -18,7 +18,11 @@ class C extends B {
   void foo([x]) {
     // But it is a problem to try to pass `x` along to super, since the super
     // method is A.foo.
-    super.foo(/*@compile-error=unspecified*/ x);
+    super.foo(x);
+    //       ^
+    // [cfe] Too many positional arguments: 0 allowed, but 1 found.
+    //        ^
+    // [analyzer] COMPILE_TIME_ERROR.EXTRA_POSITIONAL_ARGUMENTS
   }
 }
 

tests/language/assign/top_method_test.dart

@@ -10,5 +10,10 @@ method() {
 
 main() {
   // Illegal, can't change a top level method
-  /*@compile-error=unspecified*/ method = () { return 1; };
+  method = () {
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.ASSIGNMENT_TO_FUNCTION
+// [cfe] Setter not found: 'method'.
+    return 1;
+  };
 }

tests/language_2/abstract/beats_arguments_test.dart

@@ -14,5 +14,8 @@ abstract class A {
 }
 
 void main() {
-  /*@compile-error=unspecified*/ new A();
+  new A();
+  //  ^
+  // [analyzer] COMPILE_TIME_ERROR.INSTANTIATE_ABSTRACT_CLASS
+  // [cfe] The class 'A' is abstract and can't be instantiated.
 }

tests/language_2/abstract/override_adds_optional_args_concrete_subclass_test.dart

@@ -16,7 +16,11 @@ abstract class B extends A {
   void foo([x]);
 }
 
-class /*@compile-error=unspecified*/ C extends B {
+class C extends B {
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_IMPLEMENTATION_OVERRIDE
+// [cfe] The implementation of 'foo' in the non-abstract class 'C' does not conform to its interface.
+
   // However, there is a problem here because this class is concrete and doesn't
   // override foo.
 }

tests/language_2/abstract/override_adds_optional_args_concrete_test.dart

@@ -9,9 +9,13 @@ class A {
 }
 
 class B extends A {
+//    ^
+// [analyzer] COMPILE_TIME_ERROR.INVALID_IMPLEMENTATION_OVERRIDE
+// [cfe] The implementation of 'foo' in the non-abstract class 'B' does not conform to its interface.
+
   // This class declaration violates soundness, since it allows `new
   // B().foo(42)`, which would lead to invalid arguments being passed to A.foo.
-  void /*@compile-error=unspecified*/ foo([x]);
+  void foo([x]);
 }
 
 void f(B b) {

tests/language_2/abstract/override_adds_optional_args_supercall_test.dart

@@ -20,7 +20,11 @@ class C extends B {
   void foo([x]) {
     // But it is a problem to try to pass `x` along to super, since the super
     // method is A.foo.
-    super.foo(/*@compile-error=unspecified*/ x);
+    super.foo(x);
+    //       ^
+    // [cfe] Too many positional arguments: 0 allowed, but 1 found.
+    //        ^
+    // [analyzer] COMPILE_TIME_ERROR.EXTRA_POSITIONAL_ARGUMENTS
   }
 }
 

tests/language_2/assign/top_method_test.dart

@@ -12,5 +12,10 @@ method() {
 
 main() {
   // Illegal, can't change a top level method
-  /*@compile-error=unspecified*/ method = () { return 1; };
+  method = () {
+//^^^^^^
+// [analyzer] COMPILE_TIME_ERROR.ASSIGNMENT_TO_FUNCTION
+// [cfe] Setter not found: 'method'.
+    return 1;
+  };
 }