[clang] bcf9e91 - [Clang] Fix a regression introduced by #161163. (#162612)

[via cfe-commits]

Author: Corentin Jabot
Date: 2025-10-15T11:54:04+02:00
New Revision: bcf9e917142de4a5c4799b4debe7d11500cee426

URL: https://github.com/llvm/llvm-project/commit/bcf9e917142de4a5c4799b4debe7d11500cee426
DIFF: https://github.com/llvm/llvm-project/commit/bcf9e917142de4a5c4799b4debe7d11500cee426.diff

LOG: [Clang] Fix a regression introduced by #161163. (#162612)

Classes with a user provided constructor are still implicit lifetime if
they have an implicit, trivial copy ctr.

Added: 
    

Modified: 
    clang/lib/Sema/SemaTypeTraits.cpp
    clang/test/SemaCXX/type-traits.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaTypeTraits.cpp b/clang/lib/Sema/SemaTypeTraits.cpp
index 3e34675cbf064..aca21cc793170 100644
--- a/clang/lib/Sema/SemaTypeTraits.cpp
+++ b/clang/lib/Sema/SemaTypeTraits.cpp
@@ -1076,8 +1076,7 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
     if (T.isPODType(C) || T->isObjCLifetimeType())
       return true;
     if (CXXRecordDecl *RD = C.getBaseElementType(T)->getAsCXXRecordDecl()) {
-      if (RD->hasTrivialDefaultConstructor() &&
-          !RD->hasNonTrivialDefaultConstructor())
+      if (RD->hasTrivialDefaultConstructor())
         return true;
 
       bool FoundConstructor = false;
@@ -1165,14 +1164,26 @@ static bool EvaluateUnaryTypeTrait(Sema &Self, TypeTrait UTT,
     const CXXDestructorDecl *Dtor = RD->getDestructor();
     if (UnqualT->isAggregateType() && (!Dtor || !Dtor->isUserProvided()))
       return true;
-    if (RD->hasTrivialDestructor() && (!Dtor || !Dtor->isDeleted())) {
-      for (CXXConstructorDecl *Ctr : RD->ctors()) {
-        if (Ctr->isIneligibleOrNotSelected() || Ctr->isDeleted())
-          continue;
-        if (Ctr->isTrivial())
-          return true;
-      }
+    bool HasTrivialNonDeletedDtr =
+        RD->hasTrivialDestructor() && (!Dtor || !Dtor->isDeleted());
+    if (!HasTrivialNonDeletedDtr)
+      return false;
+    for (CXXConstructorDecl *Ctr : RD->ctors()) {
+      if (Ctr->isIneligibleOrNotSelected() || Ctr->isDeleted())
+        continue;
+      if (Ctr->isTrivial())
+        return true;
     }
+    if (RD->needsImplicitDefaultConstructor() &&
+        RD->hasTrivialDefaultConstructor() &&
+        !RD->hasNonTrivialDefaultConstructor())
+      return true;
+    if (RD->needsImplicitCopyConstructor() && RD->hasTrivialCopyConstructor() &&
+        !RD->defaultedCopyConstructorIsDeleted())
+      return true;
+    if (RD->needsImplicitMoveConstructor() && RD->hasTrivialMoveConstructor() &&
+        !RD->defaultedMoveConstructorIsDeleted())
+      return true;
     return false;
   }
   case UTT_IsIntangibleType:

diff  --git a/clang/test/SemaCXX/type-traits.cpp b/clang/test/SemaCXX/type-traits.cpp
index 901d510bba847..9ef44d0346b48 100644
--- a/clang/test/SemaCXX/type-traits.cpp
+++ b/clang/test/SemaCXX/type-traits.cpp
@@ -2066,7 +2066,28 @@ class UserProvidedConstructor {
     UserProvidedConstructor(const UserProvidedConstructor&)            = delete;
     UserProvidedConstructor& operator=(const UserProvidedConstructor&) = delete;
 };
+struct Ctr {
+  Ctr();
+};
+struct Ctr2 {
+  Ctr2();
+private:
+  NoEligibleTrivialContructor inner;
+};
+
+struct NonCopyable{
+    NonCopyable() = default;
+    NonCopyable(const NonCopyable&) = delete;
+};
+
+class C {
+    NonCopyable nc;
+};
 
+static_assert(__builtin_is_implicit_lifetime(Ctr));
+static_assert(!__builtin_is_implicit_lifetime(Ctr2));
+static_assert(__builtin_is_implicit_lifetime(C));
+static_assert(!__builtin_is_implicit_lifetime(NoEligibleTrivialContructor));
 static_assert(__builtin_is_implicit_lifetime(NonAggregate));
 static_assert(!__builtin_is_implicit_lifetime(DataMemberInitializer));
 static_assert(!__builtin_is_implicit_lifetime(UserProvidedConstructor));
@@ -2076,9 +2097,27 @@ template <typename T>
 class Tpl {
     Tpl() requires false = default ;
 };
-static_assert(!__builtin_is_implicit_lifetime(Tpl<int>));
+static_assert(__builtin_is_implicit_lifetime(Tpl<int>));
+
+template <typename>
+class MultipleDefaults {
+  MultipleDefaults() {};
+  MultipleDefaults() requires true = default;
+};
+static_assert(__builtin_is_implicit_lifetime(MultipleDefaults<int>));
+template <typename>
+class MultipleDefaults2 {
+  MultipleDefaults2() requires true {};
+  MultipleDefaults2() = default;
+};
+
+static_assert(__builtin_is_implicit_lifetime(MultipleDefaults2<int>));
+
 
 #endif
+
+
+
 }
 
 void is_signed()