[messages] Consume types from messages.yaml files.

Now that all diagnostic codes in analyzer-style `messages.yaml` files
have a `type:` entry, it can safely be used to determine the
diagnostic's type. This replaces the old logic that inferred
diagnostic types from the diagnostic's class name (diagnostics under
the heading `CompileTimeErrorCode` have type `compileTimeError`, those
under `StaticWarningCode` have type `staticWarning`, etc).

This paves the way for removing the notion of diagnostic code class
entirely.

Change-Id: I6a6a69646fdcaccaef6f8c32a1ebf303a54548d8
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/464283
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>

pkg/analyzer/test/verify_diagnostics_test.dart

@@ -371,7 +371,7 @@ class DocumentationValidator {
         }
         for (int i = 0; i < exampleSnippets.length; i++) {
           _SnippetData snippet = exampleSnippets[i];
-          if (message.analyzerCode.diagnosticClass == linterLintCodeInfo) {
+          if (message.type == AnalyzerDiagnosticType.lint) {
             snippet.lintCode = codeName;
           }
           await _validateSnippet('example', i, snippet);
@@ -386,7 +386,7 @@ class DocumentationValidator {
           if (firstExample != null) {
             snippet.auxiliaryFiles.addAll(firstExample.auxiliaryFiles);
           }
-          if (message.analyzerCode.diagnosticClass == linterLintCodeInfo) {
+          if (message.type == AnalyzerDiagnosticType.lint) {
             snippet.lintCode = codeName;
           }
           await _validateSnippet('fixes', i, snippet);

pkg/analyzer_utilities/lib/analyzer_messages.dart

@@ -311,15 +311,24 @@ enum AnalyzerDiagnosticPackage {
   analyzer(
     diagnosticPathPart: 'src/diagnostic/diagnostic',
     dirName: 'analyzer',
+    permittedTypes: {
+      .compileTimeError,
+      .hint,
+      .staticWarning,
+      .syntacticError,
+      .todo,
+    },
   ),
   analysisServer(
     diagnosticPathPart: 'src/diagnostic',
     dirName: 'analysis_server',
+    permittedTypes: {.compileTimeError},
     shouldIgnorePreferSingleQuotes: true,
   ),
   linter(
     diagnosticPathPart: 'src/diagnostic',
     dirName: 'linter',
+    permittedTypes: {.lint},
     shouldIgnorePreferExpressionFunctionBodies: true,
     shouldIgnorePreferSingleQuotes: true,
   );
@@ -335,6 +344,9 @@ enum AnalyzerDiagnosticPackage {
   /// file will be `pkg/linter/lib/src/diagnostic/diagnostic.g.dart`.
   final String diagnosticPathPart;
 
+  /// The set of [AnalyzerDiagnosticType]s that may be used in this package.
+  final Set<AnalyzerDiagnosticType> permittedTypes;
+
   /// Whether code generated in this package needs an "ignore" comment to ignore
   /// the `prefer_expression_function_bodies` lint.
   final bool shouldIgnorePreferExpressionFunctionBodies;
@@ -346,6 +358,7 @@ enum AnalyzerDiagnosticPackage {
   const AnalyzerDiagnosticPackage({
     required this.diagnosticPathPart,
     required this.dirName,
+    required this.permittedTypes,
     this.shouldIgnorePreferExpressionFunctionBodies = false,
     this.shouldIgnorePreferSingleQuotes = false,
   });
@@ -415,7 +428,7 @@ class AnalyzerMessage extends Message with MessageWithAnalyzerCode {
   final AnalyzerDiagnosticPackage package;
 
   @override
-  final AnalyzerDiagnosticType? type;
+  final AnalyzerDiagnosticType type;
 
   factory AnalyzerMessage(
     MessageYaml messageYaml, {
@@ -450,7 +463,6 @@ class AnalyzerMessage extends Message with MessageWithAnalyzerCode {
        type = messageYaml.get(
          'type',
          decode: MessageWithAnalyzerCode.decodeType,
-         ifAbsent: () => null,
        ),
        super(messageYaml) {
     // Ignore extra keys related to analyzer example-based tests.
@@ -545,7 +557,7 @@ mixin MessageWithAnalyzerCode on Message {
       (value) =>
           value != null && value.any((part) => part is TemplateParameterPart),
     );
-    var baseClasses = analyzerCode.diagnosticClass.type.baseClasses;
+    var baseClasses = type.baseClasses;
     if (parameters.isNotEmpty && !usesParameters) {
       throw 'Error code declares parameters using a `parameters` entry, but '
           "doesn't use them";
@@ -595,9 +607,8 @@ mixin MessageWithAnalyzerCode on Message {
   /// The package into which this error code will be generated.
   AnalyzerDiagnosticPackage get package;
 
-  /// The type of this diagnostic, if present in `messages.yaml`. Otherwise
-  /// `null`.
-  AnalyzerDiagnosticType? get type;
+  /// The type of this diagnostic.
+  AnalyzerDiagnosticType get type;
 
   void outputConstantHeader(StringSink out) {
     out.write(toAnalyzerComments(indent: '  '));
@@ -617,7 +628,7 @@ mixin MessageWithAnalyzerCode on Message {
     var diagnosticCode = analyzerCode.snakeCaseName;
     var correctionMessage = this.correctionMessage;
     String? withArgumentsName;
-    var baseClasses = analyzerCode.diagnosticClass.type.baseClasses;
+    var baseClasses = type.baseClasses;
     var ConstantStyle(:concreteClassName, :staticType) = constantStyle;
     if (constantStyle case WithArgumentsConstantStyle(
       :var withArgumentsParams,
@@ -662,7 +673,7 @@ LocatableDiagnostic $withArgumentsName({$withArgumentsParams}) {
       constant.writeln('isUnresolvedIdentifier:true,');
     }
     if (baseClasses.requiresTypeArgument) {
-      constant.writeln('type: ${diagnosticClassInfo.type.code},');
+      constant.writeln('type: ${type.code},');
     }
     String uniqueName = analyzerCode.toString().replaceFirst(
       'LinterLintCode.',

pkg/analyzer_utilities/lib/messages.dart

@@ -451,7 +451,7 @@ class DiagnosticTables {
             .add(message);
         var package = message.package;
         var type = message.type;
-        if (type != null && analyzerCode.diagnosticClass.type != type) {
+        if (analyzerCode.diagnosticClass.type != type) {
           throw LocatedError(
             'Diagnostic type is ${type.name}, but its diagnostic class '
             '(${analyzerCode.diagnosticClass.name}) implies a type of '
@@ -459,6 +459,13 @@ class DiagnosticTables {
             span: message.keySpan,
           );
         }
+        if (!package.permittedTypes.contains(type)) {
+          throw LocatedError(
+            'Diagnostic type is ${type.name}, which may not be used in '
+            'package:${package.dirName}',
+            span: message.keySpan,
+          );
+        }
         if (!message.isRemoved && message is! AliasMessage) {
           (activeMessagesByPackage[package] ??= []).add(message);
         }
@@ -935,7 +942,7 @@ class SharedMessage extends CfeStyleMessage with MessageWithAnalyzerCode {
   final bool hasPublishedDocs;
 
   @override
-  final AnalyzerDiagnosticType? type;
+  final AnalyzerDiagnosticType type;
 
   SharedMessage(super.messageYaml)
     : analyzerCode = messageYaml.get(
@@ -946,7 +953,6 @@ class SharedMessage extends CfeStyleMessage with MessageWithAnalyzerCode {
       type = messageYaml.get(
         'type',
         decode: MessageWithAnalyzerCode.decodeType,
-        ifAbsent: () => null,
       );
 
   @override