Add support for parsing, but not capturing, assers in constructor initializer lists

pkg/analyzer/lib/src/task/options.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library analyzer.src.task.options;
 
 import 'dart:collection';
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/plugin/options.dart';
@@ skipping 27 matching lines @@
 
 /// Configure this [context] based on configuration details specified in
 /// the given [options].  If [options] is `null`, default values are applied.
 void configureContextOptions(
         AnalysisContext context, Map<String, Object> options) =>
     _processor.configure(context, options);
 
 /// `analyzer` analysis options constants.
 class AnalyzerOptions {
   static const String analyzer = 'analyzer';
+  static const String enableAssertInitializer = 'enableAssertInitializer';
   static const String enableAsync = 'enableAsync';
   static const String enableGenericMethods = 'enableGenericMethods';
   static const String enableStrictCallChecks = 'enableStrictCallChecks';
   static const String enableSuperMixins = 'enableSuperMixins';
 
   static const String errors = 'errors';
   static const String exclude = 'exclude';
   static const String language = 'language';
   static const String plugins = 'plugins';
   static const String strong_mode = 'strong-mode';
@@ skipping 19 matching lines @@
   static const List<String> topLevel = const [
     errors,
     exclude,
     language,
     plugins,
     strong_mode
   ];
 
   /// Supported `analyzer` language configuration options.
   static const List<String> languageOptions = const [
+    enableAssertInitializer,
     enableAsync,
     enableGenericMethods,
     enableStrictCallChecks,
     enableSuperMixins
   ];
 }
 
 /// Validates `analyzer` options.
 class AnalyzerOptionsValidator extends CompositeValidator {
   AnalyzerOptionsValidator()
@@ skipping 374 matching lines @@
     if (excludes is YamlList) {
       List<String> excludeList = toStringList(excludes);
       if (excludeList != null) {
         context.setConfigurationData(CONTEXT_EXCLUDES, excludeList);
       }
     }
   }
 
   void setLanguageOption(
       AnalysisContext context, Object feature, Object value) {
+    if (feature == AnalyzerOptions.enableAssertInitializer) {
+      if (isTrue(value)) {
+        AnalysisOptionsImpl options =
+            new AnalysisOptionsImpl.from(context.analysisOptions);
+        options.enableAssertInitializer = true;
+        context.analysisOptions = options;
+      }
+    }
     if (feature == AnalyzerOptions.enableAsync) {
       if (isFalse(value)) {
         AnalysisOptionsImpl options =
             new AnalysisOptionsImpl.from(context.analysisOptions);
         options.enableAsync = false;
         context.analysisOptions = options;
       }
     }
     if (feature == AnalyzerOptions.enableStrictCallChecks) {
       if (isTrue(value)) {
@@ skipping 54 matching lines @@
         options.strongMode = strongMode;
         context.analysisOptions = options;
       }
     }
   }
 
   void _applyLanguageOption(
       AnalysisOptionsImpl options, Object feature, Object value) {
     bool boolValue = toBool(value);
     if (boolValue != null) {
-      if (feature == AnalyzerOptions.enableAsync) {
+      if (feature == AnalyzerOptions.enableAssertInitializer) {
+        options.enableAssertInitializer = boolValue;
+      } else if (feature == AnalyzerOptions.enableAsync) {
         options.enableAsync = boolValue;
-      }
-      if (feature == AnalyzerOptions.enableSuperMixins) {
+      } else if (feature == AnalyzerOptions.enableSuperMixins) {
         options.enableSuperMixins = boolValue;
-      }
-      if (feature == AnalyzerOptions.enableGenericMethods) {
+      } else if (feature == AnalyzerOptions.enableGenericMethods) {
         options.enableGenericMethods = boolValue;
       }
     }
   }
 
   void _applyLanguageOptions(AnalysisOptionsImpl options, Object configs) {
     if (configs is YamlMap) {
       configs.nodes.forEach((key, value) {
         if (key is YamlScalar && value is YamlScalar) {
           String feature = key.value?.toString();
@@ skipping 28 matching lines @@
         }
       });
     } else if (config is Map) {
       options.strongMode = true;
       config.forEach((k, v) => _applyStrongModeOption(options, k, v));
     } else {
       options.strongMode = config is bool ? config : false;
     }
   }
 }