[llvm] [clang] Fix handling of adding a file with the same name as an existing dir to VFS (PR #94461)

[via llvm-commits]

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@@ -893,6 +893,10 @@ bool InMemoryFileSystem::addFile(const Twine &P, time_t ModificationTime,
     }
 
     if (auto *NewDir = dyn_cast<detail::InMemoryDirectory>(Node)) {
+      // Trying to insert a file in place of a directory.
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jensmassberg wrote:

With the refactored code we cover the case that a directory is added

https://github.com/llvm/llvm-project/pull/94461