[Don't Commit] For playing modules

[ChuanqiXu]

Summary

This is a fake patch for developers to observe the features of named modules easily. This is not intended to be merged.

clang/lib/Sema/SemaDecl.cpp

Sema::ActOnFunctionDeclarator(Scope *S, Declarator &D, DeclContext *DC,
   if (getLangOpts().CPlusPlus) {
     // The rules for implicit inlines changed in C++20 for methods and friends
     // with an in-class definition (when such a definition is not attached to
     // the global module).  User-specified 'inline' overrides this (set when
     // the function decl is created above).
     // FIXME: We need a better way to separate C++ standard and clang modules.
     bool ImplicitInlineCXX20 = !getLangOpts().CPlusPlusModules ||
                                !NewFD->getOwningModule() ||
-                               NewFD->getOwningModule()->isGlobalModule() ||
+                               // NewFD->getOwningModule()->isGlobalModule() ||
                                NewFD->getOwningModule()->isHeaderLikeModule();
     bool isInline = D.getDeclSpec().isInlineSpecified();
     bool isVirtual = D.getDeclSpec().isVirtualSpecified();
     bool hasExplicit = D.getDeclSpec().hasExplicitSpecifier();
     isFriend = D.getDeclSpec().isFriendSpecified();
     if (isFriend && !isInline && D.isFunctionDefinition()) {
       // Pre-C++20 [class.friend]p5
       //   A function can be defined in a friend declaration of a

clang/lib/Sema/SemaLookup.cpp

if (M && !LookupModulesCache.insert(M).second)
       M = nullptr;
     CodeSynthesisContextLookupModules.push_back(M);
   }
   return LookupModulesCache;
 }
 
 /// Determine if we could use all the declarations in the module.
 bool Sema::isUsableModule(const Module *M) {
+  return true;
   assert(M && "We shouldn't check nullness for module here");
   // Return quickly if we cached the result.
   if (UsableModuleUnitsCache.count(M))
     return true;
 
   // If M is the global module fragment of the current translation unit. So it
   // should be usable.
   // [module.global.frag]p1: