[cfe/shared] Polish messages_suite; add more examples to messages.yaml

 * No more "Fail" status in messages.status.
 * Removed unused messages.
 * Added examples for (almost?) all messages where it's possible.
 * Add messages suite to coverage suite and update coverage.

== Additional notes

=== From the yaml spec (https://yaml.org/spec/1.2.2/)

```
2.3. Scalars
Scalar content can be written in block notation, using a literal style (indicated by “|”) where all line breaks are significant. Alternatively, they can be written with the folded style (denoted by “>”) where each line break is folded to a space unless it ends an empty or a more-indented line.
```

So we should probably use `|` and not `>` for code (especially if starting with a comment line (e.g. `// @Dart=3.1`)) - and the other way around for messages.

=== These three settings

```
exampleAllowOtherCodes: true
exampleAllowMultipleReports: true
includeErrorContext: true
```

(or some combination of them)
closes #53634.

(one already existed, but was renamed)

Change-Id: I91a8ecee88d0600015252e289b068f60b1d1aeeb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/444600
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Jens Johansen <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>

Author: jensjoha

pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart

@@ -1202,7 +1202,6 @@ abstract class AbstractScanner implements Scanner {
     }
 
     if (next == $BACKSLASH) {
-      // Coverage-ignore-block(suite): Not run.
       // Hit when parsing doc comments in the analyzer.
       appendPrecedenceToken(TokenType.BACKSLASH);
       return advance();

pkg/_fe_analyzer_shared/lib/src/scanner/abstract_scanner.dart

@@ -2794,10 +2794,6 @@ ParserErrorCode.EXTENSION_TYPE_WITH:
   status: needsEvaluation
 ParserErrorCode.EXTERNAL_CLASS:
   status: hasFix
-ParserErrorCode.EXTERNAL_CONSTRUCTOR_WITH_BODY:
-  status: needsFix
-  notes: |-
-    Remove the `external` keyword.
 ParserErrorCode.EXTERNAL_CONSTRUCTOR_WITH_FIELD_INITIALIZERS:
   status: needsFix
   notes: |-
@@ -2816,10 +2812,6 @@ ParserErrorCode.EXTERNAL_FACTORY_WITH_BODY:
   status: needsFix
   notes: |-
     Remove the `external` keyword, or remove the body of the factory.
-ParserErrorCode.EXTERNAL_FIELD:
-  status: needsFix
-  notes: |-
-    Remove the `external` keyword.
 ParserErrorCode.EXTERNAL_GETTER_WITH_BODY:
   status: needsFix
   notes: |-

pkg/analysis_server/lib/src/services/correction/error_fix_status.yaml

@@ -77,7 +77,7 @@ final fastaAnalyzerErrorCodes = <DiagnosticCode?>[
   ParserErrorCode.invalidSuperInInitializer,
   ParserErrorCode.experimentNotEnabled,
   ParserErrorCode.externalMethodWithBody,
-  ParserErrorCode.externalField,
+  ParserErrorCode.abstractFinalInterfaceClass,
   ParserErrorCode.abstractClassMember,
   ParserErrorCode.breakOutsideOfLoop,
   ParserErrorCode.classInClass,
@@ -114,7 +114,7 @@ final fastaAnalyzerErrorCodes = <DiagnosticCode?>[
   ParserErrorCode.catchSyntax,
   ParserErrorCode.externalFactoryRedirection,
   ParserErrorCode.externalFactoryWithBody,
-  ParserErrorCode.externalConstructorWithBody,
+  ParserErrorCode.externalConstructorWithFieldInitializers,
   ParserErrorCode.fieldInitializedOutsideDeclaringClass,
   ParserErrorCode.varAndType,
   ParserErrorCode.invalidInitializer,
@@ -204,8 +204,6 @@ final fastaAnalyzerErrorCodes = <DiagnosticCode?>[
   ParserErrorCode.extraneousModifierInExtensionType,
   ParserErrorCode.extraneousModifierInPrimaryConstructor,
   ParserErrorCode.abstractFinalBaseClass,
-  ParserErrorCode.abstractFinalInterfaceClass,
-  ParserErrorCode.externalConstructorWithFieldInitializers,
 ];
 
 class ParserErrorCode extends DiagnosticCode {
@@ -789,14 +787,6 @@ class ParserErrorCode extends DiagnosticCode {
     correctionMessage: "Try removing the keyword 'external'.",
   );
 
-  static const ParserErrorCode externalConstructorWithBody = ParserErrorCode(
-    'EXTERNAL_CONSTRUCTOR_WITH_BODY',
-    "External constructors can't have a body.",
-    correctionMessage:
-        "Try removing the body of the constructor, or removing the keyword "
-        "'external'.",
-  );
-
   static const ParserErrorCode externalConstructorWithFieldInitializers =
       ParserErrorCode(
         'EXTERNAL_CONSTRUCTOR_WITH_FIELD_INITIALIZERS',
@@ -832,14 +822,6 @@ class ParserErrorCode extends DiagnosticCode {
         "'external'.",
   );
 
-  static const ParserErrorCode externalField = ParserErrorCode(
-    'EXTERNAL_FIELD',
-    "Fields can't be declared to be 'external'.",
-    correctionMessage:
-        "Try removing the keyword 'external', or replacing the field by an "
-        "external getter and/or setter.",
-  );
-
   /// No parameters.
   static const ParserErrorCode externalGetterWithBody = ParserErrorCode(
     'EXTERNAL_GETTER_WITH_BODY',

pkg/analyzer/lib/src/dart/error/syntactic_errors.g.dart

@@ -737,13 +737,11 @@ const List<DiagnosticCode> diagnosticCodeValues = [
   ParserErrorCode.extensionTypeExtends,
   ParserErrorCode.extensionTypeWith,
   ParserErrorCode.externalClass,
-  ParserErrorCode.externalConstructorWithBody,
   ParserErrorCode.externalConstructorWithFieldInitializers,
   ParserErrorCode.externalConstructorWithInitializer,
   ParserErrorCode.externalEnum,
   ParserErrorCode.externalFactoryRedirection,
   ParserErrorCode.externalFactoryWithBody,
-  ParserErrorCode.externalField,
   ParserErrorCode.externalGetterWithBody,
   ParserErrorCode.externalLateField,
   ParserErrorCode.externalMethodWithBody,

pkg/analyzer/lib/src/diagnostic/diagnostic_code_values.g.dart

@@ -283,7 +283,6 @@ class CompilerOptions {
             experimentReleasedVersionForTesting);
   }
 
-  // Coverage-ignore(suite): Not run.
   bool equivalent(CompilerOptions other,
       {bool ignoreOnDiagnostic = true,
       bool ignoreVerbose = true,
@@ -294,9 +293,11 @@ class CompilerOptions {
       return false;
     }
     if (!ignoreOnDiagnostic) {
+      // Coverage-ignore-block(suite): Not run.
       if (onDiagnostic != other.onDiagnostic) return false;
     }
     if (packagesFileUri != other.packagesFileUri) return false;
+    // Coverage-ignore-block(suite): Not run.
     if (!equalLists(additionalDills, other.additionalDills)) return false;
     if (sdkSummary != other.sdkSummary) return false;
     if (dynamicInterfaceSpecificationUri !=

pkg/front_end/lib/src/api_prototype/compiler_options.dart

@@ -92,7 +92,6 @@ class MemoryFileSystemEntity implements FileSystemEntity {
   Future<bool> existsAsyncIfPossible() => exists();
 
   @override
-  // Coverage-ignore(suite): Not run.
   Future<Uint8List> readAsBytes() {
     Uint8List? contents = _fileSystem._files[uri];
     if (contents == null) {
@@ -118,7 +117,6 @@ class MemoryFileSystemEntity implements FileSystemEntity {
     }
   }
 
-  // Coverage-ignore(suite): Not run.
   /// Writes the given raw bytes to this file system entity.
   ///
   /// If no file exists, one is created.  If a file exists already, it is
@@ -127,11 +125,11 @@ class MemoryFileSystemEntity implements FileSystemEntity {
     if (bytes is Uint8List) {
       _update(uri, bytes);
     } else {
+      // Coverage-ignore-block(suite): Not run.
       _update(uri, new Uint8List.fromList(bytes));
     }
   }
 
-  // Coverage-ignore(suite): Not run.
   /// Writes the given string to this file system entity.
   ///
   /// The string is encoded as UTF-8.
@@ -142,7 +140,6 @@ class MemoryFileSystemEntity implements FileSystemEntity {
     _update(uri, utf8.encode(s));
   }
 
-  // Coverage-ignore(suite): Not run.
   void _update(Uri uri, Uint8List data) {
     if (_fileSystem._directories.contains(uri)) {
       throw new FileSystemException(uri, 'Entry $uri is a directory.');

pkg/front_end/lib/src/api_prototype/memory_file_system.dart

@@ -135,7 +135,6 @@ PlainAndColorizedString formatNoSourceLine(
       _colorizeMessageText(severity, messageTextPlain);
 
   if (message.uri != null) {
-    // Coverage-ignore-block(suite): Not run.
     String path = relativizeUri(Uri.base, message.uri!, isWindows);
     return new PlainAndColorizedString(
       formatErrorMessage(null, null, length, path, messageTextPlain),

pkg/front_end/lib/src/base/command_line_reporting.dart

@@ -17,6 +17,7 @@ import 'compiler_context.dart' show CompilerContext;
 import 'file_system_dependency_tracker.dart';
 import 'uri_translator.dart' show UriTranslator;
 
+// Coverage-ignore(suite): Not run.
 Future<List<Uri>> getDependencies(Uri script,
     {Uri? sdk,
     Uri? packages,

pkg/front_end/lib/src/base/get_dependencies.dart

@@ -19,8 +19,7 @@ class HybridFileSystem implements FileSystem {
   final FileSystem physical;
 
   HybridFileSystem(this.memory, [FileSystem? _physical])
-      : physical = _physical ?? // Coverage-ignore(suite): Not run.
-            StandardFileSystem.instance;
+      : physical = _physical ?? StandardFileSystem.instance;
 
   @override
   FileSystemEntity entityForUri(Uri uri) =>
@@ -43,21 +42,16 @@ class HybridFileSystemEntity implements FileSystemEntity {
       return _delegate!;
     }
     FileSystemEntity entity = _fs.memory.entityForUri(uri);
-    if (((!uri.isScheme('file') &&
-                // Coverage-ignore(suite): Not run.
-                !uri.isScheme('data')) &&
-            // Coverage-ignore(suite): Not run.
+    if (((!uri.isScheme('file') && !uri.isScheme('data')) &&
             _fs.physical is StandardFileSystem) ||
         await entity.exists()) {
-      // Coverage-ignore-block(suite): Not run.
       _delegate = entity;
       return _delegate!;
     }
     return _delegate = _fs.physical.entityForUri(uri);
   }
 
   @override
-  // Coverage-ignore(suite): Not run.
   Future<bool> exists() async => (await delegate).exists();
 
   @override