[clang] [ASTWriter] Detect more non-affecting FileIDs to reduce source location duplication (PR #112015)

[Ilya Biryukov via cfe-commits]

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@@ -192,13 +201,13 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
 
       // The containing module map is affecting, because it's being pointed
       // into by Module::DefinitionLoc.
-      if (auto FE = MM.getContainingModuleMapFile(Mod))
-        ModuleMaps.insert(*FE);
+      if (auto F = MM.getContainingModuleMapFileID(Mod); F.isValid())
+        ModuleMaps.insert(F);
       // For inferred modules, the module map that allowed inferring is not
       // related to the virtual containing module map file. It did affect the
       // compilation, though.
-      if (auto FE = MM.getModuleMapFileForUniquing(Mod))
-        ModuleMaps.insert(*FE);
+      if (auto F = MM.getModuleMapFileIDForUniquing(Mod); F.isValid())
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ilya-biryukov wrote:

I've updated the second occurrence to use a different name (went with `UniqF` to avoid line breaks).
The same name did not bother me because it's scoped to just 2 lines, but I was still happy to update if you feel it's better.

https://github.com/llvm/llvm-project/pull/112015