[clang] [clang][Lex] Replace push_back with emplace_back for vector insertions (PR #232260)

[Chen Miao via cfe-commits]

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@@ -737,6 +737,11 @@ class alignas(8) Module {
 
     /// The message provided to the user when there is a conflict.
     std::string Message;
+
+    /// Construct an unresolved conflict.
+    UnresolvedConflict() = default;
+    UnresolvedConflict(ModuleId Id, std::string Message)
+        : Id(Id), Message(Message) {}
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ChenMiaoi wrote:

Yes, that fixes the additional copies. However, it still performs a copy followed by a move for `Id`, just like the original implementation.

https://github.com/llvm/llvm-project/pull/232260