[clang] [Clang][Sema] Fix wrong initialization kind when handling initializing structured bindings from an array with direct-list-initialization (PR #124793)

Yanzuo Liu via cfe-commits cfe-commits at lists.llvm.org
Mon Feb 3 20:29:39 PST 2025


https://github.com/zwuis updated https://github.com/llvm/llvm-project/pull/124793

>From 16596add29b63ee0282e026dec7b1d5946863113 Mon Sep 17 00:00:00 2001
From: Yanzuo Liu <zwuis at outlook.com>
Date: Wed, 29 Jan 2025 00:38:15 +0800
Subject: [PATCH 1/3] Fix wrong initialization kind

---
 clang/lib/Sema/SemaInit.cpp                |  5 +++--
 clang/test/SemaCXX/cxx1z-decomposition.cpp | 21 ++++++++++-----------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index b95cbbf4222056..5552fce55f1310 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -4861,8 +4861,9 @@ static void TryListInitialization(Sema &S,
             S.Context.hasSameUnqualifiedType(SubInit[0]->getType(), DestType) &&
             "Deduced to other type?");
         TryArrayCopy(S,
-                     InitializationKind::CreateCopy(Kind.getLocation(),
-                                                    InitList->getLBraceLoc()),
+                     InitializationKind::CreateDirect(Kind.getLocation(),
+                                                      InitList->getLBraceLoc(),
+                                                      InitList->getRBraceLoc()),
                      Entity, SubInit[0], DestType, Sequence,
                      TreatUnavailableAsInvalid);
         if (Sequence)
diff --git a/clang/test/SemaCXX/cxx1z-decomposition.cpp b/clang/test/SemaCXX/cxx1z-decomposition.cpp
index a8914fe4e9cd82..b3d98e44990f61 100644
--- a/clang/test/SemaCXX/cxx1z-decomposition.cpp
+++ b/clang/test/SemaCXX/cxx1z-decomposition.cpp
@@ -200,38 +200,37 @@ namespace lambdas {
 
 namespace by_value_array_copy {
   struct explicit_copy {
-    explicit_copy() = default; // expected-note 2{{candidate constructor not viable: requires 0 arguments, but 1 was provided}}
-    explicit explicit_copy(const explicit_copy&) = default; // expected-note 2{{explicit constructor is not a candidate}}
+    explicit_copy() = default; // expected-note {{candidate constructor not viable: requires 0 arguments, but 1 was provided}}
+    explicit explicit_copy(const explicit_copy&) = default; // expected-note {{explicit constructor is not a candidate}}
   };
 
   constexpr int direct_initialization_for_elements() {
     explicit_copy ec_arr[2];
     auto [a1, b1](ec_arr);
+    auto [a2, b2]{ec_arr};
 
     int arr[3]{1, 2, 3};
-    auto [a2, b2, c2](arr);
+    auto [a3, b3, c3](arr);
+    auto [a4, b4, c4]{arr}; // GH31813
     arr[0]--;
-    return a2 + b2 + c2 + arr[0];
+    return a3 + b3 + c3 + a4 + b4 + c4 + arr[0];
   }
-  static_assert(direct_initialization_for_elements() == 6);
+  static_assert(direct_initialization_for_elements() == 12);
 
   constexpr int copy_initialization_for_elements() {
     int arr[2]{4, 5};
     auto [a1, b1] = arr;
-    auto [a2, b2]{arr}; // GH31813
     arr[0] = 0;
-    return a1 + b1 + a2 + b2 + arr[0];
+    return a1 + b1 + arr[0];
   }
-  static_assert(copy_initialization_for_elements() == 18);
+  static_assert(copy_initialization_for_elements() == 9);
 
   void copy_initialization_for_elements_with_explicit_copy_ctor() {
     explicit_copy ec_arr[2];
     auto [a1, b1] = ec_arr; // expected-error {{no matching constructor for initialization of 'explicit_copy[2]'}}
-    auto [a2, b2]{ec_arr}; // expected-error {{no matching constructor for initialization of 'explicit_copy[2]'}}
 
     // Test prvalue
     using T = explicit_copy[2];
-    auto [a3, b3] = T{};
-    auto [a4, b4]{T{}};
+    auto [a2, b2] = T{};
   }
 } // namespace by_value_array_copy

>From ad033c917db457ebe68b4556a482e9ba56b4746d Mon Sep 17 00:00:00 2001
From: Yanzuo Liu <zwuis at outlook.com>
Date: Wed, 29 Jan 2025 10:28:21 +0800
Subject: [PATCH 2/3] Make tests more clear

---
 clang/test/SemaCXX/cxx1z-decomposition.cpp | 39 ++++++++++------------
 1 file changed, 17 insertions(+), 22 deletions(-)

diff --git a/clang/test/SemaCXX/cxx1z-decomposition.cpp b/clang/test/SemaCXX/cxx1z-decomposition.cpp
index b3d98e44990f61..95c64bc3b8bff6 100644
--- a/clang/test/SemaCXX/cxx1z-decomposition.cpp
+++ b/clang/test/SemaCXX/cxx1z-decomposition.cpp
@@ -204,33 +204,28 @@ namespace by_value_array_copy {
     explicit explicit_copy(const explicit_copy&) = default; // expected-note {{explicit constructor is not a candidate}}
   };
 
-  constexpr int direct_initialization_for_elements() {
-    explicit_copy ec_arr[2];
-    auto [a1, b1](ec_arr);
-    auto [a2, b2]{ec_arr};
-
-    int arr[3]{1, 2, 3};
-    auto [a3, b3, c3](arr);
-    auto [a4, b4, c4]{arr}; // GH31813
-    arr[0]--;
-    return a3 + b3 + c3 + a4 + b4 + c4 + arr[0];
-  }
-  static_assert(direct_initialization_for_elements() == 12);
+  constexpr int simple_array_elements() {
+    int arr[2]{1, 2};
+
+    auto [a1, a2] = arr;
+    auto [b1, b2](arr);
+    auto [c1, c2]{arr}; // GH31813
 
-  constexpr int copy_initialization_for_elements() {
-    int arr[2]{4, 5};
-    auto [a1, b1] = arr;
     arr[0] = 0;
-    return a1 + b1 + arr[0];
+    return arr[0] + a1 + a2 + b1 + b2 + c1 + c2;
   }
-  static_assert(copy_initialization_for_elements() == 9);
+  static_assert(simple_array_elements() == 9);
 
-  void copy_initialization_for_elements_with_explicit_copy_ctor() {
-    explicit_copy ec_arr[2];
-    auto [a1, b1] = ec_arr; // expected-error {{no matching constructor for initialization of 'explicit_copy[2]'}}
+  void explicit_copy_ctor_array_elements() {
+    explicit_copy ec_arr[1];
+
+    auto [a] = ec_arr; // expected-error {{no matching constructor for initialization of 'explicit_copy[1]'}}
+    auto [b](ec_arr);
+    auto [c]{ec_arr};
 
     // Test prvalue
-    using T = explicit_copy[2];
-    auto [a2, b2] = T{};
+    using T = explicit_copy[1];
+    auto [d] = T{};
   }
+
 } // namespace by_value_array_copy

>From 88f702e64396300ec2f07f6960379f6617bcbf0e Mon Sep 17 00:00:00 2001
From: Yanzuo Liu <zwuis at outlook.com>
Date: Tue, 4 Feb 2025 12:27:57 +0800
Subject: [PATCH 3/3] Add assertion

---
 clang/lib/Sema/SemaInit.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 5552fce55f1310..916afbbe80e7af 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -4860,6 +4860,9 @@ static void TryListInitialization(Sema &S,
         assert(
             S.Context.hasSameUnqualifiedType(SubInit[0]->getType(), DestType) &&
             "Deduced to other type?");
+        assert(Kind.getKind() == clang::InitializationKind::IK_DirectList &&
+               "List-initialize structured bindings but not "
+               "direct-list-initialization?");
         TryArrayCopy(S,
                      InitializationKind::CreateDirect(Kind.getLocation(),
                                                       InitList->getLBraceLoc(),



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