[clang-tools-extra] [clang-tidy] performance-unnecessary-copy-init: Add a hook... (PR #73921)

[Clement Courbet via cfe-commits]

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@@ -302,6 +303,20 @@ void UnnecessaryCopyInitialization::check(
   }
 }
 
+void UnnecessaryCopyInitialization::makeDiagnostic(
+    DiagnosticBuilder Diagnostic, const VarDecl &Var, const Stmt &BlockStmt,
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legrosbuffle wrote:

I can't really do that because each of the two uses of this function are streaming one description-dependent parameter (`IsConstQualified` for one and `OldVar` for the other). These are even different types. So it feels simpler to stream before entering the function, so that the function only holds logic which is common to both callers.

https://github.com/llvm/llvm-project/pull/73921