phase3: generated l10n/messages_all, events, actions, dialog null-safe

lib/generated/intl/messages_all.dart

@@ -24,7 +24,7 @@ Map<String, LibraryLoader> _deferredLibraries = {
   'zh_CN': () => new Future.value(null),
 };
 
-MessageLookupByLibrary _findExact(String localeName) {
+MessageLookupByLibrary? _findExact(String localeName) {
   switch (localeName) {
     case 'en':
       return messages_en.messages;
@@ -59,7 +59,7 @@ bool _messagesExistFor(String locale) {
   }
 }
 
-MessageLookupByLibrary _findGeneratedMessagesFor(String locale) {
+MessageLookupByLibrary? _findGeneratedMessagesFor(String locale) {
   var actualLocale = Intl.verifiedLocale(locale, _messagesExistFor,
       onFailure: (_) => null);
   if (actualLocale == null) return null;

lib/generated/l10n.dart

@@ -15,7 +15,7 @@ import 'intl/messages_all.dart';
 class S {
   S();
   
-  static S current;
+  static S current = S();
   
   static const AppLocalizationDelegate delegate =
     AppLocalizationDelegate();
@@ -32,7 +32,7 @@ class S {
   } 
 
   static S of(BuildContext context) {
-    return Localizations.of<S>(context, S);
+    return Localizations.of<S>(context, S) ?? S.current;
   }
 
   /// `About`