Make Intl generated code pass most current lint options

Trying this again, but reverted the "new" removal and one additional type in generated code, as the generated code is used in Dart 1 projects that are still active.

Mostly using ignore_for_file, but fixing a few of the most obvious issues
Started out as integrating dart-archive/intl_translation#31 but then expanded.
Cloned from CL 264686901 by 'g4 patch'.
Original change by alanknight@alanknight:intl_maintenance:290:citc on 2019/08/21 14:02:13.

PiperOrigin-RevId: 264925581

Author: Dart Team

pkgs/intl_translation/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 0.17.6
   * Strip indentation from generated JSON output to improve codesize.
+  * Make generated code not trigger most lints, either by fixing issues
+    or by using lots of ignore_for_file directives.
 
 ## 0.17.5
   * Allow multiple ARB files with the same locale and combine

pkgs/intl_translation/lib/generate_localized.dart

@@ -57,7 +57,7 @@ class MessageGeneration {
   /// so it's left undefined.
   String package;
 
-  get releaseMode => codegenMode == 'release';
+  bool get releaseMode => codegenMode == 'release';
 
   bool get jsonMode => false;
 
@@ -105,10 +105,8 @@ class MessageGeneration {
     for (var translation in usableTranslations) {
       // Some messages we generate as methods in this class. Simpler ones
       // we inline in the map from names to messages.
-      var messagesThatNeedMethods = translation.originalMessages
-          .where((each) => _hasArguments(each))
-          .toSet()
-          .toList();
+      var messagesThatNeedMethods =
+          translation.originalMessages.where(_hasArguments).toSet().toList();
       for (var original in messagesThatNeedMethods) {
         output
           ..write("  ")
@@ -153,22 +151,21 @@ class MessageGeneration {
 // messages from the main program should be duplicated here with the same
 // function name.
 
-// ignore_for_file: unnecessary_brace_in_string_interps
+// Ignore issues from commonly used lints in this file.
+// ignore_for_file:unnecessary_brace_in_string_interps, unnecessary_new
+// ignore_for_file:prefer_single_quotes,comment_references, directives_ordering
+// ignore_for_file:annotate_overrides,prefer_generic_function_type_aliases
+// ignore_for_file:unused_import, file_names
 
 import 'package:$intlImportPath/intl.dart';
 import 'package:$intlImportPath/message_lookup_by_library.dart';
 $extraImports
-// ignore: unnecessary_new
 final messages = new MessageLookup();
 
-// ignore: unused_element
-final _keepAnalysisHappy = Intl.defaultLocale;
-
-// ignore: non_constant_identifier_names
-typedef MessageIfAbsent(String message_str, List<dynamic> args);
+typedef String MessageIfAbsent(String messageStr, List<dynamic> args);
 
 class MessageLookup extends MessageLookupByLibrary {
-  get localeName => '$locale';
+  String get localeName => '$locale';
 
 """ +
       (releaseMode ? overrideLookup : "");
@@ -185,7 +182,6 @@ class MessageLookup extends MessageLookupByLibrary {
       // If there's no message_str, then we are an internal lookup, e.g. an
       // embedded plural, and shouldn't fail.
       if (message_str == null) return null;
-      // ignore: unnecessary_new
       throw new UnsupportedError(
           "No translation found for message '\$name',\\n"
           "  original text '\$message_str'");
@@ -215,12 +211,11 @@ class MessageLookup extends MessageLookupByLibrary {
       var locale = Intl.canonicalizedLocale(rawLocale);
       var loadOperation = (useDeferredLoading)
           ? "  '$locale': ${libraryName(locale)}.loadLibrary,\n"
-          : "// ignore: unnecessary_new\n"
-              "  '$locale': () => new Future.value(null),\n";
+          : "  '$locale': () => new Future.value(null),\n";
       output.write(loadOperation);
     }
     output.write("};\n");
-    output.write("\nMessageLookupByLibrary _findExact(localeName) {\n"
+    output.write("\nMessageLookupByLibrary _findExact(String localeName) {\n"
         "  switch (localeName) {\n");
     for (var rawLocale in allLocales) {
       var locale = Intl.canonicalizedLocale(rawLocale);
@@ -238,11 +233,17 @@ class MessageLookup extends MessageLookupByLibrary {
 // This is a library that looks up messages for specific locales by
 // delegating to the appropriate library.
 
+// Ignore issues from commonly used lints in this file.
+// ignore_for_file:implementation_imports, file_names, unnecessary_new
+// ignore_for_file:unnecessary_brace_in_string_interps, directives_ordering
+// ignore_for_file:argument_type_not_assignable, invalid_assignment
+// ignore_for_file:prefer_single_quotes, prefer_generic_function_type_aliases
+// ignore_for_file:comment_references
+
 import 'dart:async';
 
 import 'package:$intlImportPath/intl.dart';
 import 'package:$intlImportPath/message_lookup_by_library.dart';
-// ignore: implementation_imports
 import 'package:$intlImportPath/src/intl_helpers.dart';
 
 """;
@@ -260,16 +261,12 @@ Future<bool> initializeMessages(String localeName) async {
     (locale) => _deferredLibraries[locale] != null,
     onFailure: (_) => null);
   if (availableLocale == null) {
-    // ignore: unnecessary_new
     return new Future.value(false);
   }
   var lib = _deferredLibraries[availableLocale];
-  // ignore: unnecessary_new
   await (lib == null ? new Future.value(false) : lib());
-  // ignore: unnecessary_new
   initializeInternalMessageLookup(() => new CompositeMessageLookup());
   messageLookup.addLocale(availableLocale, _findGeneratedMessagesFor);
-  // ignore: unnecessary_new
   return new Future.value(true);
 }
 
@@ -281,7 +278,7 @@ bool _messagesExistFor(String locale) {
   }
 }
 
-MessageLookupByLibrary _findGeneratedMessagesFor(locale) {
+MessageLookupByLibrary _findGeneratedMessagesFor(String locale) {
   var actualLocale = Intl.verifiedLocale(locale, _messagesExistFor,
       onFailure: (_) => null);
   if (actualLocale == null) return null;
@@ -329,8 +326,8 @@ import '${generatedFilePrefix}messages_all.dart' show evaluateJsonTemplate;
       Iterable<TranslatedMessage> usableTranslations, String locale) {
     output.write(r"""
   var _messages;
-  // ignore: unnecessary_new
-  get messages => _messages ??= new JsonDecoder().convert(messageText);
+  get messages => _messages ??=
+      const JsonDecoder().convert(messageText) as Map<String, dynamic>;
 """);
 
     output.write("  static final messageText = ");
@@ -358,7 +355,7 @@ import '${generatedFilePrefix}messages_all.dart' show evaluateJsonTemplate;
 ///   * \['Intl.gender', String gender, (templates for female, male, other)\]
 ///   * \['Intl.select', String choice, { 'case' : template, ...} \]
 ///   * \['text alternating with ', 0 , ' indexes in the argument list'\]
-String evaluateJsonTemplate(Object input, List<dynamic> args) {
+String evaluateJsonTemplate(dynamic input, List<dynamic> args) {
   if (input == null) return null;
   if (input is String) return input;
   if (input is int) {
@@ -398,7 +395,6 @@ String evaluateJsonTemplate(Object input, List<dynamic> args) {
 
    // If we get this far, then we are a basic interpolation, just strings and
    // ints.
-   // ignore: unnecessary_new
    var output = new StringBuffer();
    for (var entry in template) {
      if (entry is int) {