[clang] [Clang][diagnostics] Fix structured binding shadows template param loc (PR #129116)

[Amr Hesham via cfe-commits]

https://github.com/AmrDeveloper created https://github.com/llvm/llvm-project/pull/129116

Fix structured binding shadows template parameter location

Fixes: #129060

>From ed0cf3f026e439288f8334f27555ad26825fd56a Mon Sep 17 00:00:00 2001
From: AmrDeveloper <amr96 at programmer.net>
Date: Thu, 27 Feb 2025 21:49:32 +0100
Subject: [PATCH] [Clang][diagnostics] Fix structured binding shadows template
 parameter location

---
 clang/lib/Sema/SemaDeclCXX.cpp                 | 3 +--
 clang/test/CXX/temp/temp.res/temp.local/p6.cpp | 5 +++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 664d48ccbc382..a3a028b9485d6 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -883,8 +883,7 @@ Sema::ActOnDecompositionDeclarator(Scope *S, Declarator &D,
     // It's not permitted to shadow a template parameter name.
     if (Previous.isSingleResult() &&
         Previous.getFoundDecl()->isTemplateParameter()) {
-      DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
-                                      Previous.getFoundDecl());
+      DiagnoseTemplateParameterShadow(B.NameLoc, Previous.getFoundDecl());
       Previous.clear();
     }
 
diff --git a/clang/test/CXX/temp/temp.res/temp.local/p6.cpp b/clang/test/CXX/temp/temp.res/temp.local/p6.cpp
index 00bb35813c39a..e464bb5e7eaef 100644
--- a/clang/test/CXX/temp/temp.res/temp.local/p6.cpp
+++ b/clang/test/CXX/temp/temp.res/temp.local/p6.cpp
@@ -162,3 +162,8 @@ struct A {
 };
 A<0>::B a;
 }
+
+template <typename T> void shadow9() {  // expected-note{{template parameter is declared here}}
+  using arr = int[1]; // expected-warning at +1 {{decomposition declarations are a C++17 extension}}
+  auto [T] = arr{}; // expected-error {{declaration of 'T' shadows template parameter}}
+}