[clang] [clang][Modules] Diagnosing Module Redefinition Across ModuleMaps (PR #190085)

[Cyndy Ishida via cfe-commits]

================
@@ -1756,9 +1756,24 @@ void ModuleMapLoader::handleModuleDecl(const modulemap::ModuleDecl &MD) {
   if (Module *Existing = Map.lookupModuleQualified(ModuleName, ActiveModule)) {
     // We might see a (re)definition of a module that we already have a
     // definition for in four cases:
-    //  - If we loaded one definition from an AST file and we've just found a
-    //    corresponding definition in a module map file, or
+    //  - If we loaded one definition from an AST file and we've just found the
+    //    corresponding definition in the same module map file, or
----------------
cyndyishida wrote:

IIUC, I think it might be clearer to change the comment to be 

>  If the module was loaded from an AST file and we've found its original definition again (same source module map) 

That way, you don't need to repeat the same information in the comment on line 1763


https://github.com/llvm/llvm-project/pull/190085