Migrate to nullsafety

Author: XinyueZ

as2f/src/main/resources/dart_i18n.mvel

@@ -27,8 +27,8 @@ class GeneratedLocalizationsDelegate extends LocalizationsDelegate<S> {
     ];
   }
 
-  LocaleListResolutionCallback listResolution({Locale fallback}) {
-    return (List<Locale> locales, Iterable<Locale> supported) {
+  LocaleListResolutionCallback listResolution({Locale? fallback}) {
+    return (List<Locale>? locales, Iterable<Locale> supported) {
       if (locales == null || locales.isEmpty) {
         return fallback ?? supported.first;
       } else {
@@ -37,51 +37,53 @@ class GeneratedLocalizationsDelegate extends LocalizationsDelegate<S> {
     };
   }
 
-  LocaleResolutionCallback resolution({Locale fallback}) {
-    return (Locale locale, Iterable<Locale> supported) {
+  LocaleResolutionCallback resolution({Locale? fallback}) {
+    return (Locale? locale, Iterable<Locale> supported) {
       return _resolve(locale, fallback, supported);
     };
   }
 
-  Locale _resolve(Locale locale, Locale fallback, Iterable<Locale> supported) {
+  Locale _resolve(Locale? locale, Locale? fallback, Iterable<Locale> supported) {
     if (locale == null || !isSupported(locale)) {
       return fallback ?? supported.first;
     }
 
     final Locale languageLocale = Locale(locale.languageCode, "");
     if (supported.contains(locale)) {
       return locale;
-    } else if (supported.contains(languageLocale)) {
+    } else if (supported!.contains(languageLocale)) {
       return languageLocale;
     } else {
-      final Locale fallbackLocale = fallback ?? supported.first;
+      final Locale fallbackLocale = fallback ?? supported!.first;
       return fallbackLocale;
     }
   }
 
   @override
-  Future<S> load(Locale locale) {
-    final String lang = getLang(locale);
+  Future<S> load(Locale? locale) {
+    final String? lang = getLang(locale);
     if (lang != null) {
       switch (lang) {
-@foreach{locale : locales}        case "@{locale.value}": return SynchronousFuture<S>(const @{'$'}@{locale.value}());@end{'\n'}
+        case "en":
+          return SynchronousFuture<S>(const $en());
+        case "de":
+          return SynchronousFuture<S>(const $de());
         default:
-          // NO-OP.
+        // NO-OP.
       }
     }
     return SynchronousFuture<S>(const S());
   }
 
   @override
-  bool isSupported(Locale locale) =>
-    locale != null && supportedLocales.contains(locale);
+  bool isSupported(Locale? locale) => locale != null && supportedLocales.contains(locale);
 
   @override
   bool shouldReload(GeneratedLocalizationsDelegate old) => false;
 }
 
-String getLang(Locale l) => l == null
-  ? null
-  : l.countryCode != null && l.countryCode.isEmpty
-    ? l.languageCode
-    : l.toString();
+String? getLang(Locale? l) => l == null
+    ? null
+    : l.countryCode != null && l.countryCode!.isEmpty
+        ? l.languageCode
+        : l.toString();

as2f/src/main/resources/dart_i18n_class.mvel

@@ -5,7 +5,7 @@ class S implements WidgetsLocalizations {
   static const GeneratedLocalizationsDelegate delegate =
     GeneratedLocalizationsDelegate();
 
-  static S of(BuildContext context) => Localizations.of<S>(context, S);
+  static S of(BuildContext context) => Localizations.of<S>(context, S) ?? S();
 
   @override
   TextDirection get textDirection => TextDirection.@{textDirection.value};

as2f/src/main/resources/dart_i18n_quantity.mvel

@@ -1,7 +1,10 @@
 String @{key}(@{emitArgs()}) {
     plural_rules.startRuleEvaluation(quantity);
-    final pluralCase = plural_rules.pluralRules["@{locale}"]() as plural_rules.PluralCase;
-    switch (pluralCase) {
+
+    final pluralRulesLocale = plural_rules.pluralRules["@{locale}"];
+    if (pluralRulesLocale == null) return "";
+
+    switch (pluralRulesLocale()) {
 @foreach{item : items}      case plural_rules.PluralCase.@{item.quantity.value}: return "@{item.value}";@end{'\n'}
       default: return "";
     }