[clang] [clang] Decay types of function and constant template parameter packs (PR #132189)

[via cfe-commits]

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@@ -1277,19 +1278,27 @@ QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
     TSI = SubstAutoTypeSourceInfoDependent(TSI);
   }
 
-  return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
+  return CheckNonTypeTemplateParameterType(TSI->getType(), Loc, Diagnose);
 }
 
-bool Sema::RequireStructuralType(QualType T, SourceLocation Loc) {
+bool Sema::RequireStructuralType(QualType T, SourceLocation Loc,
+                                 bool Diagnose) {
   if (T->isDependentType())
     return false;
 
-  if (RequireCompleteType(Loc, T, diag::err_template_nontype_parm_incomplete))
+  if (Diagnose ? RequireCompleteType(Loc, T,
+                                     diag::err_template_nontype_parm_incomplete)
+               : !isCompleteType(Loc, T))
     return true;
 
   if (T->isStructuralType())
     return false;
 
+  // If we're not emitting diagnostics, there's no need to figure out
+  // why exactly T is not a structural type.
+  if (!Diagnose)
+    return true;
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offsetof wrote:

Hm, there's an `isCompleteType` check a few lines above. Is that not sufficient?

https://github.com/llvm/llvm-project/pull/132189