[Clang] Partial implementation of support for P3074 (trivial unions) #146815

brevzin · 2025-07-03T03:51:56Z

This commit makes union construction/destruction trivial by default, but does not add the lifetime aspects of the paper — am holding out until P3726R0 will be discussed which alters that approach somewhat based on feedback from Richard Smith. But the constructor/destructor part is common regardless and also simpler.

llvmbot · 2025-07-03T03:52:29Z

@llvm/pr-subscribers-clang

Author: Barry Revzin (brevzin)

Changes

This commit makes union construction/destruction trivial by default, but does not add the lifetime aspects of the paper — am holding out until P3726R0 will be discussed which alters that approach somewhat based on feedback from Richard Smith. But the constructor/destructor part is common regardless and also simpler.

Full diff: https://github.com/llvm/llvm-project/pull/146815.diff

6 Files Affected:

(modified) clang/lib/AST/DeclCXX.cpp (+6-3)
(modified) clang/lib/Sema/SemaDeclCXX.cpp (+15-1)
(modified) clang/test/CXX/drs/cwg6xx.cpp (+2-2)
(modified) clang/test/CXX/special/class.ctor/p5-0x.cpp (+8-7)
(modified) clang/test/CXX/special/class.ctor/p6-0x.cpp (+15-13)
(modified) clang/test/CXX/special/class.dtor/p5-0x.cpp (+17-16)

diff --git a/clang/lib/AST/DeclCXX.cpp b/clang/lib/AST/DeclCXX.cpp
index ccb308e103253..49adbdf1c393d 100644
--- a/clang/lib/AST/DeclCXX.cpp
+++ b/clang/lib/AST/DeclCXX.cpp
@@ -1217,6 +1217,9 @@ void CXXRecordDecl::addedMember(Decl *D) {
     // those because they are always unnamed.
     bool IsZeroSize = Field->isZeroSize(Context);
 
+    // P3074
+    const bool TrivialUnion = Context.getLangOpts().CPlusPlus26 && isUnion();
+
     if (const auto *RecordTy = T->getAs<RecordType>()) {
       auto *FieldRec = cast<CXXRecordDecl>(RecordTy->getDecl());
       if (FieldRec->getDefinition()) {
@@ -1277,7 +1280,7 @@ void CXXRecordDecl::addedMember(Decl *D) {
         //    -- for all the non-static data members of its class that are of
         //       class type (or array thereof), each such class has a trivial
         //       default constructor.
-        if (!FieldRec->hasTrivialDefaultConstructor())
+        if (!FieldRec->hasTrivialDefaultConstructor() && !TrivialUnion)
           data().HasTrivialSpecialMembers &= ~SMF_DefaultConstructor;
 
         // C++0x [class.copy]p13:
@@ -1315,9 +1318,9 @@ void CXXRecordDecl::addedMember(Decl *D) {
         if (!FieldRec->hasTrivialMoveAssignment())
           data().HasTrivialSpecialMembers &= ~SMF_MoveAssignment;
 
-        if (!FieldRec->hasTrivialDestructor())
+        if (!FieldRec->hasTrivialDestructor() && !TrivialUnion)
           data().HasTrivialSpecialMembers &= ~SMF_Destructor;
-        if (!FieldRec->hasTrivialDestructorForCall())
+        if (!FieldRec->hasTrivialDestructorForCall() && !TrivialUnion)
           data().HasTrivialSpecialMembersForCall &= ~SMF_Destructor;
         if (!FieldRec->hasIrrelevantDestructor())
           data().HasIrrelevantDestructor = false;
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index e8c65025bfe6d..e9b45bf99620c 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9511,6 +9511,15 @@ bool SpecialMemberDeletionInfo::shouldDeleteForSubobjectCall(
   CXXMethodDecl *Decl = SMOR.getMethod();
   FieldDecl *Field = Subobj.dyn_cast<FieldDecl*>();
 
+  // P3074: default ctor and dtor for unions are not deleted, regardless of
+  // whether the underlying fields have non-trivial or deleted versions of those
+  // members
+  if (S.Context.getLangOpts().CPlusPlus26)
+    if (Field && Field->getParent()->isUnion() &&
+        (CSM == CXXSpecialMemberKind::DefaultConstructor ||
+         CSM == CXXSpecialMemberKind::Destructor))
+      return false;
+
   int DiagKind = -1;
 
   if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::NoMemberOrDeleted)
@@ -9774,7 +9783,8 @@ bool SpecialMemberDeletionInfo::shouldDeleteForField(FieldDecl *FD) {
 
       // At least one member in each anonymous union must be non-const
       if (CSM == CXXSpecialMemberKind::DefaultConstructor &&
-          AllVariantFieldsAreConst && !FieldRecord->field_empty()) {
+          AllVariantFieldsAreConst && !FieldRecord->field_empty() &&
+          !this->S.Context.getLangOpts().CPlusPlus26) {
         if (Diagnose)
           S.Diag(FieldRecord->getLocation(),
                  diag::note_deleted_default_ctor_all_const)
@@ -9804,6 +9814,10 @@ bool SpecialMemberDeletionInfo::shouldDeleteForAllConstMembers() {
   // default constructor. Don't do that.
   if (CSM == CXXSpecialMemberKind::DefaultConstructor && inUnion() &&
       AllFieldsAreConst) {
+
+    if (S.Context.getLangOpts().CPlusPlus26)
+      return false;
+
     bool AnyFields = false;
     for (auto *F : MD->getParent()->fields())
       if ((AnyFields = !F->isUnnamedBitField()))
diff --git a/clang/test/CXX/drs/cwg6xx.cpp b/clang/test/CXX/drs/cwg6xx.cpp
index e2eb009508b52..dd54bb5295b56 100644
--- a/clang/test/CXX/drs/cwg6xx.cpp
+++ b/clang/test/CXX/drs/cwg6xx.cpp
@@ -4,7 +4,7 @@
 // RUN: %clang_cc1 -std=c++17 %s -verify=expected,cxx11-20,cxx98-17,cxx11-17,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++20 %s -verify=expected,cxx11-20,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++23 %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
-// RUN: %clang_cc1 -std=c++2c %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++2c %s -verify=expected,since-cxx11,cxx26 -fexceptions -fcxx-exceptions -pedantic-errors
 
 #if __cplusplus == 199711L
 #define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
@@ -922,7 +922,7 @@ namespace cwg667 { // cwg667: 8
 
   struct B { ~B() = delete; };
   union C { B b; };
-  static_assert(!__is_trivially_destructible(C), "");
+  static_assert(!__is_trivially_destructible(C), ""); // cxx26-error {{failed}}
 
   struct D { D(const D&) = delete; };
   struct E : D {};
diff --git a/clang/test/CXX/special/class.ctor/p5-0x.cpp b/clang/test/CXX/special/class.ctor/p5-0x.cpp
index e0c53058f892b..97a8b035a0705 100644
--- a/clang/test/CXX/special/class.ctor/p5-0x.cpp
+++ b/clang/test/CXX/special/class.ctor/p5-0x.cpp
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 -Wno-deprecated-builtins -Wno-defaulted-function-deleted
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,until26 %s -std=c++11 -Wno-deprecated-builtins -Wno-defaulted-function-deleted
+// RUN: %clang_cc1 -fsyntax-only -verify=expected %s -std=c++26 -Wno-deprecated-builtins -Wno-defaulted-function-deleted
 
 struct DefaultedDefCtor1 {};
 struct DefaultedDefCtor2 { DefaultedDefCtor2() = default; };
@@ -23,8 +24,8 @@ int n;
 
 // - X is a union-like class that has a variant member with a non-trivial
 // default constructor,
-union Deleted1a { UserProvidedDefCtor u; }; // expected-note {{default constructor of 'Deleted1a' is implicitly deleted because variant field 'u' has a non-trivial default constructor}}
-Deleted1a d1a; // expected-error {{implicitly-deleted default constructor}}
+union Deleted1a { UserProvidedDefCtor u; }; // until26-note {{default constructor of 'Deleted1a' is implicitly deleted because variant field 'u' has a non-trivial default constructor}}
+Deleted1a d1a; // until26-error {{implicitly-deleted default constructor}}
 union NotDeleted1a { DefaultedDefCtor1 nu; };
 NotDeleted1a nd1a;
 union NotDeleted1b { DefaultedDefCtor2 nu; };
@@ -86,19 +87,19 @@ NotDeleted3i nd3i;
 union Deleted4a {
   const int a;
   const int b;
-  const UserProvidedDefCtor c; // expected-note {{because variant field 'c' has a non-trivial default constructor}}
+  const UserProvidedDefCtor c; // until26-note {{because variant field 'c' has a non-trivial default constructor}}
 };
-Deleted4a d4a; // expected-error {{implicitly-deleted default constructor}}
+Deleted4a d4a; // until26-error {{implicitly-deleted default constructor}}
 union NotDeleted4a { const int a; int b; };
 NotDeleted4a nd4a;
 
 // - X is a non-union class and all members of any anonymous union member are of
 // const-qualified type (or array thereof),
 struct Deleted5a {
-  union { const int a; }; // expected-note {{because all data members of an anonymous union member are const-qualified}}
+  union { const int a; }; // until26-note {{because all data members of an anonymous union member are const-qualified}}
   union { int b; };
 };
-Deleted5a d5a; // expected-error {{implicitly-deleted default constructor}}
+Deleted5a d5a; // until26-error {{implicitly-deleted default constructor}}
 struct NotDeleted5a { union { const int a; int b; }; union { const int c; int d; }; };
 NotDeleted5a nd5a;
 
diff --git a/clang/test/CXX/special/class.ctor/p6-0x.cpp b/clang/test/CXX/special/class.ctor/p6-0x.cpp
index 156a2b20c6b52..6ce1b06841ab4 100644
--- a/clang/test/CXX/special/class.ctor/p6-0x.cpp
+++ b/clang/test/CXX/special/class.ctor/p6-0x.cpp
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,until26 %s -std=c++11
+// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx26 %s -std=c++26
 
 // Implicitly-defined default constructors are constexpr if the implicit
 // definition would be.
@@ -15,8 +16,9 @@ constexpr NonConstexpr2a nc2a = NonConstexpr2a(); // ok, does not call construct
 constexpr int nc2_a = NonConstexpr2().nl.a; // ok
 constexpr int nc2a_a = NonConstexpr2a().a; // ok
 struct Helper {
-  friend constexpr NonConstexpr1::NonConstexpr1(); // expected-error {{follows non-constexpr declaration}}
-  friend constexpr NonConstexpr2::NonConstexpr2(); // expected-error {{follows non-constexpr declaration}}
+  friend constexpr NonConstexpr1::NonConstexpr1(); // until26-error {{follows non-constexpr declaration}} cxx26-error {{missing exception specification}}
+  friend constexpr NonConstexpr2::NonConstexpr2(); // until26-error {{follows non-constexpr declaration}} cxx26-error {{missing exception specification}}
+
 };
 
 struct Constexpr1 {};
@@ -31,14 +33,14 @@ constexpr Constexpr2 c2 = Constexpr2(); // ok
 
 int n;
 struct Member {
-  Member() : a(n) {}
+  Member() : a(n) {} // cxx26-note {{here}}
   constexpr Member(int&a) : a(a) {}
   int &a;
 };
-struct NonConstexpr4 { // expected-note {{here}}
+struct NonConstexpr4 { // until26-note {{here}} cxx26-note {{non-constexpr constructor}}
   Member m;
 };
-constexpr NonConstexpr4 nc4 = NonConstexpr4(); // expected-error {{constant expression}} expected-note {{non-constexpr constructor 'NonConstexpr4'}}
+constexpr NonConstexpr4 nc4 = NonConstexpr4(); // expected-error {{constant expression}} until26-note {{non-constexpr constructor 'NonConstexpr4'}} cxx26-note {{in call to}}
 struct Constexpr3 {
   constexpr Constexpr3() : m(n) {}
   Member m;
@@ -53,11 +55,11 @@ constexpr Constexpr4 c4 = Constexpr4(); // ok
 // This rule breaks some legal C++98 programs!
 struct A {}; // expected-note {{here}}
 struct B {
-  friend A::A(); // expected-error {{non-constexpr declaration of 'A' follows constexpr declaration}}
+  friend A::A(); // until26-error {{non-constexpr declaration of 'A' follows constexpr declaration}} cxx26-error {{missing exception specification}}
 };
 
 namespace UnionCtors {
-  union A { // expected-note {{here}}
+  union A { // until26-note {{here}}
     int a;
     int b;
   };
@@ -79,7 +81,7 @@ namespace UnionCtors {
       int d = 5;
     };
   };
-  struct E { // expected-note {{here}}
+  struct E { // until26-note {{here}}
     union {
       int a;
       int b;
@@ -87,11 +89,11 @@ namespace UnionCtors {
   };
 
   struct Test {
-    friend constexpr A::A() noexcept; // expected-error {{follows non-constexpr declaration}}
+    friend constexpr A::A() noexcept; // until26-error {{follows non-constexpr declaration}}
     friend constexpr B::B() noexcept;
     friend constexpr C::C() noexcept;
     friend constexpr D::D() noexcept;
-    friend constexpr E::E() noexcept; // expected-error {{follows non-constexpr declaration}}
+    friend constexpr E::E() noexcept; // until26-error {{follows non-constexpr declaration}}
   };
 }
 
@@ -122,6 +124,6 @@ namespace PR48763 {
 
   struct G { G(); };
   struct H : D { using D::D; H(int); G g; };
-  union V { H h; }; // expected-note {{field 'h' has a non-trivial default constructor}}
-  V v; // expected-error {{deleted}}
+  union V { H h; }; // until26-note {{field 'h' has a non-trivial default constructor}}
+  V v; // until26-error {{deleted}}
 }
diff --git a/clang/test/CXX/special/class.dtor/p5-0x.cpp b/clang/test/CXX/special/class.dtor/p5-0x.cpp
index ae14dcdaf102a..7616383515e0a 100644
--- a/clang/test/CXX/special/class.dtor/p5-0x.cpp
+++ b/clang/test/CXX/special/class.dtor/p5-0x.cpp
@@ -1,10 +1,11 @@
-// RUN: %clang_cc1 -verify -std=c++11 %s -Wno-defaulted-function-deleted -triple x86_64-linux-gnu
+// RUN: %clang_cc1 -verify=expected,until26 -std=c++11 %s -Wno-defaulted-function-deleted -triple x86_64-linux-gnu
+// RUN: %clang_cc1 -verify=expected -std=c++26 %s -Wno-defaulted-function-deleted -triple x86_64-linux-gnu
 
 struct NonTrivDtor {
   ~NonTrivDtor();
 };
 struct DeletedDtor {
-  ~DeletedDtor() = delete; // expected-note 5 {{deleted here}}
+  ~DeletedDtor() = delete; // expected-note 4+ {{deleted here}}
 };
 class InaccessibleDtor {
   ~InaccessibleDtor() = default;
@@ -16,28 +17,28 @@ class InaccessibleDtor {
 // destructor.
 union A1 {
   A1();
-  NonTrivDtor n; // expected-note {{destructor of 'A1' is implicitly deleted because variant field 'n' has a non-trivial destructor}}
+  NonTrivDtor n; // until26-note {{destructor of 'A1' is implicitly deleted because variant field 'n' has a non-trivial destructor}}
 };
-A1 a1; // expected-error {{deleted function}}
+A1 a1; // until26-error {{deleted function}}
 struct A2 {
   A2();
   union {
-    NonTrivDtor n; // expected-note {{because variant field 'n' has a non-trivial destructor}}
+    NonTrivDtor n; // until26-note {{because variant field 'n' has a non-trivial destructor}}
   };
 };
-A2 a2; // expected-error {{deleted function}}
+A2 a2; // until26-error {{deleted function}}
 union A3 {
   A3();
-  NonTrivDtor n[3]; // expected-note {{because variant field 'n' has a non-trivial destructor}}
+  NonTrivDtor n[3]; // until26-note {{because variant field 'n' has a non-trivial destructor}}
 };
-A3 a3; // expected-error {{deleted function}}
+A3 a3; // until26-error {{deleted function}}
 struct A4 {
   A4();
   union {
-    NonTrivDtor n[3]; // expected-note {{because variant field 'n' has a non-trivial destructor}}
+    NonTrivDtor n[3]; // until26-note {{because variant field 'n' has a non-trivial destructor}}
   };
 };
-A4 a4; // expected-error {{deleted function}}
+A4 a4; // until26-error {{deleted function}}
 
 // -- any of the non-static data members has class type M (or array thereof) and
 // M has a deleted or inaccessible destructor.
@@ -63,18 +64,18 @@ struct B4 {
 B4 b4; // expected-error {{deleted function}}
 union B5 {
   B5();
-  union { // expected-note-re {{because field 'B5::(anonymous union at {{.+}})' has a deleted destructor}}
-    DeletedDtor a; // expected-note {{because field 'a' has a deleted destructor}}
+  union { // until26-note-re {{because field 'B5::(anonymous union at {{.+}})' has a deleted destructor}}
+    DeletedDtor a; // until26-note {{because field 'a' has a deleted destructor}}
   };
 };
-B5 b5; // expected-error {{deleted function}}
+B5 b5; // until26-error {{deleted function}}
 union B6 {
   B6();
-  union { // expected-note-re {{because field 'B6::(anonymous union at {{.+}})' has a deleted destructor}}
-    InaccessibleDtor a; // expected-note {{because field 'a' has an inaccessible destructor}}
+  union { // until26-note-re {{because field 'B6::(anonymous union at {{.+}})' has a deleted destructor}}
+    InaccessibleDtor a; // until26-note {{because field 'a' has an inaccessible destructor}}
   };
 };
-B6 b6; // expected-error {{deleted function}}
+B6 b6; // until26-error {{deleted function}}
 
 // -- any direct or virtual base class has a deleted or inaccessible destructor.
 struct C1 : DeletedDtor { C1(); } c1; // expected-error {{deleted function}} expected-note {{base class 'DeletedDtor' has a deleted destructor}}

clang/test/CXX/drs/cwg6xx.cpp

clang/test/CXX/special/class.ctor/p5-0x.cpp

brevzin · 2025-07-07T13:34:28Z

clang/lib/Sema/SemaDeclCXX.cpp

+    RecordDecl *Parent = Field->getParent();
+    while (Parent &&
+           (Parent->isAnonymousStructOrUnion() ||
+            (Parent->isUnion() && Parent->getIdentifier() == nullptr))) {
+      if (auto RD = dyn_cast_or_null<RecordDecl>(Parent->getParent())) {
+        Parent = RD;
+      } else {
+        break;
+      }
+    }
+
+    auto ParentDecl = dyn_cast<CXXRecordDecl>(Parent);
+    if (!ParentDecl->isBeingDefined()) {
+      Sema::SpecialMemberOverloadResult SMOR = S.LookupSpecialMember(
+          ParentDecl, CXXSpecialMemberKind::DefaultConstructor, false, false,
+          false, false, false);
+      if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::Success) {


I'm guessing this is the wrong way to do this, but I don't know how to do it better.

Also this doesn't exactly implement the wording I quoted above because the wording is just wrong (see future CWG issue here).

At least when it comes to getting the parent type, we do something similar in GetEnclosingNamedOrTopAnonRecord() in SemaBoundsSafety.cpp so I don’t think there is a helper for that.

CXXRecordDecl has hasTrivialDefaultConstructor() and friends; you might be able to make use of those here rather than performing a lookup manually (at least the check for !isBeingDefined() would imply to me that the flags that those functions query are accurate), but it’s possible I’m missing something here.

clang/test/CXX/special/class.dtor/p7.cpp

bcardosolopes

Added more reviewers and some nits

clang/lib/Sema/SemaDeclCXX.cpp

Sirraide · 2025-07-11T14:25:58Z

clang/lib/AST/DeclCXX.cpp

    bool IsZeroSize = Field->isZeroSize(Context);

+    // P3074
+    const bool TrivialUnion = Context.getLangOpts().CPlusPlus26 && isUnion();


Suggested change

const bool TrivialUnion = Context.getLangOpts().CPlusPlus26 && isUnion();

bool TrivialUnion = Context.getLangOpts().CPlusPlus26 && isUnion();

nit (we typically don’t use top-level const for local vars)

Why not? I see a lot of them btw.

I thought it was in our coding standards because I’m used to people pointing this out all the time but https://llvm.org/docs/CodingStandards.html doesn’t seem to have anything to say about it.

clang/lib/Sema/SemaDeclCXX.cpp

Sirraide · 2025-07-11T14:52:49Z

clang/test/CXX/special/class.ctor/p6-0x.cpp

 struct Helper {
-  friend constexpr NonConstexpr1::NonConstexpr1(); // expected-error {{follows non-constexpr declaration}}
-  friend constexpr NonConstexpr2::NonConstexpr2(); // expected-error {{follows non-constexpr declaration}}
+  friend constexpr NonConstexpr1::NonConstexpr1(); // cxx11-23-error {{follows non-constexpr declaration}} cxx26-error {{missing exception specification}}


That ‘is missing exception specification 'noexcept'’ error is weird; I’m also getting that before C++26 and only Clang errors on this; GCC, MSVC, and EDG seem to be fine with it. I don’t think that has anything to do w/ this patch but it’s still strange.

clang/test/CXX/special/class.dtor/p7.cpp

Sirraide · 2025-07-11T14:59:30Z

clang/test/CXX/special/class.dtor/p7.cpp

+  DeletedDtor a; // expected-note {{because field 'a' has a deleted destructor}}
+};
+B1 b1; // expected-error {{deleted function}}
+union B2 {


Some more cases:

union A { struct { NonTrivial x; // W/ and w/o a default member initialiser. }; }; A a; struct B { union { NonTrivial x; // as above }; }; B b; union { struct { union { struct { union { NonTrivial x; // as above }; }; }; }; } c; struct { union { struct { union { struct { NonTrivial x; // as above }; }; }; }; } d;

Alright I'm not handling this case correctly, but I can't figure out why:

union U9 { struct { NonTrivial x = 1; // #6 }; } u9; // expected-error {{deleted function}}

Hmm, at a glance nothing jumps out to me; we do create a FieldDecl for the anonymous struct inside the union so I’d expect this to just handle that case—maybe we’re doing something weird with IndirectFieldDecls somewhere but that’s just a guess.

I did spot a fixme about anonymous unions inside anonymous unions, so er, here’s another gross test case I suppose:

union { union { NonTrivial x; }; } a;

[P3074] Implementing part of trivial unions

40290a9

brevzin requested a review from Endilll as a code owner July 3, 2025 03:51

brevzin changed the title ~~[P3074] Parital implementation of support for trivial unions~~ [P3074] Partial implementation of support for trivial unions Jul 3, 2025

llvmbot added clang Clang issues not falling into any other category clang:frontend Language frontend issues, e.g. anything involving "Sema" labels Jul 3, 2025

Adding test case that I have to fix still

59b0649

brevzin force-pushed the p3074-pt2 branch from d070148 to 59b0649 Compare July 3, 2025 04:06

One down

e7cc4ec

Endilll reviewed Jul 3, 2025

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clang/test/CXX/special/class.ctor/p5-0x.cpp Outdated Show resolved Hide resolved

brevzin added 6 commits July 3, 2025 10:26

More accurate

5eb68c5

Test fixup

80e2476

Uh... this cannot be right

9972d7e

More test fixups

c2f3a05

What, really, this is good?

1283ddb

I don't think the other cases make sense, given that we have a field

eed0988

brevzin changed the title ~~[P3074] Partial implementation of support for trivial unions~~ [Clang] Partial implementation of support for P3074 (trivial unions) Jul 7, 2025

brevzin commented Jul 7, 2025

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shafik reviewed Jul 8, 2025

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bcardosolopes requested review from Fznamznon and Sirraide July 9, 2025 14:59

bcardosolopes reviewed Jul 9, 2025

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PR feedback

64babbc

Sirraide reviewed Jul 11, 2025

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brevzin added 2 commits July 11, 2025 16:13

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8aebb45

	const bool TrivialUnion = Context.getLangOpts().CPlusPlus26 && isUnion();
	bool TrivialUnion = Context.getLangOpts().CPlusPlus26 && isUnion();

[Clang] Partial implementation of support for P3074 (trivial unions) #146815

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[Clang] Partial implementation of support for P3074 (trivial unions) #146815

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