[clang] [clang] print correct context for diagnostics suppressed by deduction (PR #125453)

[Erich Keane via cfe-commits]

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@@ -1909,7 +1909,19 @@ class Sema final : public SemaBase {
   /// '\#pragma clang attribute push' directives to the given declaration.
   void AddPragmaAttributes(Scope *S, Decl *D);
 
-  void PrintPragmaAttributeInstantiationPoint();
+  using DiagFuncRef =
+      llvm::function_ref<void(SourceLocation, PartialDiagnostic)>;
+  auto getDefaultDiagFunc() {
+    return [this](SourceLocation Loc, PartialDiagnostic PD) {
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erichkeane wrote:

`PartialDiagnostic`, or `PDiag` don't actually have a location.  `PartialDiagnostic` is only the diag-ID, plus up to the full-list (meaning, doesn't have to be the full list) of `<<` arguments.  `PartialDiagnosticAt` is a `std::pair` for cases where you already know the location, exactly the use here.

https://github.com/llvm/llvm-project/pull/125453