[clang] [Clang] Only omit deprecation warnings for implicit special members (PR #219177)

[Corentin Jabot via cfe-commits]

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@@ -212,6 +212,10 @@ static bool ShouldDiagnoseAvailabilityInContext(
     } else if (K == AR_Deprecated) {
       if (C->isDeprecated())
         return true;
+      // Don't emit deprecated warnings when defining special member functions.
+      if (const auto *FD = dyn_cast<FunctionDecl>(C);
+          FD && FD->isDefaulted() && FD->isImplicit())
+        return true;
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cor3ntin wrote:

That seems somewhat brittle.
Can we instead check if the function is a CXXDeductionGuide?

https://github.com/llvm/llvm-project/pull/219177