[clang] Enable -Wunique-object-duplication inside templated code (PR #125902)

[Devon Loehr via cfe-commits]

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@@ -3669,6 +3669,7 @@ class Sema final : public SemaBase {
   /// cause problems if the variable is mutable, its initialization is
   /// effectful, or its address is taken.
   bool GloballyUniqueObjectMightBeAccidentallyDuplicated(const VarDecl *Dcl);
+  void DiagnoseDangerousUniqueObjectDuplication(const VarDecl *Dcl);
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DKLoehr wrote:

I think it's meaningful because it's possible for objects to be duplicated "harmlessly", in which case we don't warn because the only problem is a little extra memory usage. This is the case for constants whose initializers don't have side effects.

https://github.com/llvm/llvm-project/pull/125902