[clang] [Clang][NFC] Avoid duplication in BuildDeductionGuideForTypeAlias (PR #161948)

[Younan Zhang via cfe-commits]

https://github.com/zyn0217 created https://github.com/llvm/llvm-project/pull/161948

This addresses the post-commit review from Shafik.

>From bbb086aa3bd4bfbfa40149084c3cbad08fe5f35e Mon Sep 17 00:00:00 2001
From: Younan Zhang <zyn7109 at gmail.com>
Date: Sat, 4 Oct 2025 13:48:59 +0800
Subject: [PATCH] [Clang][NFC] Avoid duplication in
 BuildDeductionGuideForTypeAlias

This addresses the post-commit review from Shafik.
---
 clang/lib/Sema/SemaTemplateDeductionGuide.cpp | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp
index 9a61888e318b3..8ba23aa334afd 100644
--- a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp
+++ b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp
@@ -1189,14 +1189,13 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
     // parameter list of a synthesized CTAD guide. See also the FIXME in
     // test/SemaCXX/cxx20-ctad-type-alias.cpp:test25.
     Sema::CheckTemplateArgumentInfo CTAI;
+    for (auto TA : Output.arguments())
+      if (SemaRef.CheckTemplateArgument(
+              TP, TA, F, F->getLocation(), F->getLocation(),
+              /*ArgumentPackIndex=*/-1, CTAI,
+              Sema::CheckTemplateArgumentKind::CTAK_Specified))
+        return nullptr;
     if (Input.getArgument().getKind() == TemplateArgument::Pack) {
-      for (auto TA : Output.arguments()) {
-        if (SemaRef.CheckTemplateArgument(
-                TP, TA, F, F->getLocation(), F->getLocation(),
-                /*ArgumentPackIndex=*/-1, CTAI,
-                Sema::CheckTemplateArgumentKind::CTAK_Specified))
-          return nullptr;
-      }
       // We will substitute the non-deduced template arguments with these
       // transformed (unpacked at this point) arguments, where that substitution
       // requires a pack for the corresponding parameter packs.
@@ -1204,12 +1203,6 @@ BuildDeductionGuideForTypeAlias(Sema &SemaRef,
           TemplateArgument::CreatePackCopy(Context, CTAI.SugaredConverted);
     } else {
       assert(Output.arguments().size() == 1);
-      TemplateArgumentLoc Transformed = Output.arguments()[0];
-      if (SemaRef.CheckTemplateArgument(
-              TP, Transformed, F, F->getLocation(), F->getLocation(),
-              /*ArgumentPackIndex=*/-1, CTAI,
-              Sema::CheckTemplateArgumentKind::CTAK_Specified))
-        return nullptr;
       TemplateArgsForBuildingFPrime[Index] = CTAI.SugaredConverted[0];
     }
   }