[Clang] Add diagnostic reasoning for unsatisfied is_destructible trait

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1776,7 +1776,8 @@ def note_unsatisfied_trait
            "%StandardLayout{standard-layout}|"
            "%Aggregate{aggregate}|"
            "%Final{final}|"
-           "%Abstract{abstract}"
+           "%Abstract{abstract}|"
+           "%Destructible{destructible}"
            "}1">;
 
 def note_unsatisfied_trait_reason
@@ -1808,6 +1809,7 @@ def note_unsatisfied_trait_reason
            "%NonStandardLayoutMember{has a non-standard-layout member %1 of type %2}|"
            "%IndirectBaseWithFields{has an indirect base %1 with data members}|"
            "%DeletedDtr{has a %select{deleted|user-provided}1 destructor}|"
+           "%InaccessibleDtr{has a %select{private|protected}1 destructor}|"
            "%UserProvidedCtr{has a user provided %select{copy|move}1 "
            "constructor}|"
            "%UserDeclaredCtr{has a user-declared constructor}|"
@@ -1823,6 +1825,7 @@ def note_unsatisfied_trait_reason
            "%FunctionType{is a function type}|"
            "%CVVoidType{is a cv void type}|"
            "%IncompleteArrayType{is an incomplete array type}|"
+           "%IncompleteType{is an incomplete type}|"
            "%PrivateProtectedDirectDataMember{has a %select{private|protected}1 direct data member}|"
            "%PrivateProtectedDirectBase{has a %select{private|protected}1 direct base}|"
            "%NotClassOrUnion{is not a class or union type}|"
@@ -12135,11 +12138,11 @@ def err_omp_linear_ordered : Error<
   "'linear' clause cannot be specified along with 'ordered' clause with a parameter">;
 def err_omp_unexpected_schedule_modifier : Error<
   "modifier '%0' cannot be used along with modifier '%1'">;
-def err_omp_schedule_nonmonotonic_static : Error<
-  "'nonmonotonic' modifier can only be specified with 'dynamic' or 'guided' schedule kind">;
 def err_omp_incompatible_dyn_groupprivate_modifier
     : Error<"modifier '%0' cannot be used along with modifier '%1' in "
             "dyn_groupprivate">;
+def err_omp_schedule_nonmonotonic_static : Error<
+  "'nonmonotonic' modifier can only be specified with 'dynamic' or 'guided' schedule kind">;
 def err_omp_simple_clause_incompatible_with_ordered : Error<
   "'%0' clause with '%1' modifier cannot be specified if an 'ordered' clause is specified">;
 def err_omp_ordered_simd : Error<

clang/lib/Sema/SemaTypeTraits.cpp

@@ -2028,6 +2028,7 @@ static std::optional<TypeTrait> StdNameToTypeTrait(StringRef Name) {
       .Case("is_constructible", TypeTrait::TT_IsConstructible)
       .Case("is_final", TypeTrait::UTT_IsFinal)
       .Case("is_abstract", TypeTrait::UTT_IsAbstract)
+      .Case("is_destructible", TypeTrait::UTT_IsDestructible)
       .Default(std::nullopt);
 }
 
@@ -2399,6 +2400,66 @@ static void DiagnoseNonConstructibleReason(
   SemaRef.Diag(D->getLocation(), diag::note_defined_here) << D;
 }
 
+static void DiagnoseNonDestructibleReason(Sema &SemaRef, SourceLocation Loc,
+                                          QualType T) {
+
+  QualType CoreT = T.getCanonicalType();
+  if (const ArrayType *AT = SemaRef.Context.getAsArrayType(CoreT))
+    CoreT = AT->getElementType();
+
+  SemaRef.Diag(Loc, diag::note_unsatisfied_trait)
+      << CoreT << diag::TraitName::Destructible;
+
+  if (CoreT->isFunctionType()) {
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::FunctionType;
+    return;
+  }
+
+  if (CoreT->isVoidType()) {
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::CVVoidType;
+    return;
+  }
+
+  if (CoreT->isIncompleteType()) {
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::IncompleteType;
+    return;
+  }
+
+  const CXXRecordDecl *RD = CoreT->getAsCXXRecordDecl();
+  if (!RD || RD->isInvalidDecl())
+    return;
+
+  const CXXRecordDecl *Def = RD->getDefinition();
+  if (!Def) {
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::IncompleteType;
+    return;
+  }
+
+  CXXDestructorDecl *Dtor = Def->getDestructor();
+  if (!Dtor)
+    return;
+
+  if (Dtor->isDeleted()) {
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::DeletedDtr << 0
+        << Dtor->getSourceRange();
+    return;
+  }
+
+  AccessSpecifier AS = Dtor->getAccess();
+  if (AS == AS_private || AS == AS_protected) {
+    unsigned Select = AS != AS_private;
+    SemaRef.Diag(Loc, diag::note_unsatisfied_trait_reason)
+        << diag::TraitNotSatisfiedReason::InaccessibleDtr << Select
+        << Dtor->getSourceRange();
+    return;
+  }
+}
+
 static void DiagnoseNonTriviallyCopyableReason(Sema &SemaRef,
                                                SourceLocation Loc, QualType T) {
   SemaRef.Diag(Loc, diag::note_unsatisfied_trait)
@@ -2889,6 +2950,9 @@ void Sema::DiagnoseTypeTraitDetails(const Expr *E) {
   case TT_IsConstructible:
     DiagnoseNonConstructibleReason(*this, E->getBeginLoc(), Args);
     break;
+  case UTT_IsDestructible:
+    DiagnoseNonDestructibleReason(*this, E->getBeginLoc(), Args[0]);
+    break;
   case UTT_IsAggregate:
     DiagnoseNonAggregateReason(*this, E->getBeginLoc(), Args[0]);
     break;

clang/test/SemaCXX/type-traits-unsatisfied-diags-std.cpp

@@ -73,6 +73,15 @@ struct is_abstract {
 template <typename T>
 constexpr bool is_abstract_v = __is_abstract(T);
 
+template <typename T>
+struct is_destructible {
+    static constexpr bool value = __is_destructible(T);
+};
+
+template <typename T>
+constexpr bool is_destructible_v = __is_destructible(T);
+
+
 #endif
 
 #ifdef STD2
@@ -167,6 +176,17 @@ using is_abstract = __details_is_abstract<T>;
 template <typename T>
 constexpr bool is_abstract_v = __is_abstract(T);
 
+template <typename T>
+struct __details_is_destructible {
+    static constexpr bool value = __is_destructible(T);
+};
+
+template <typename T>
+using is_destructible = __details_is_destructible<T>;
+
+template <typename T>
+constexpr bool is_destructible_v = __is_destructible(T);
+
 #endif
 
 
@@ -252,6 +272,15 @@ using is_abstract = __details_is_abstract<T>;
 template <typename T>
 constexpr bool is_abstract_v = is_abstract<T>::value;
 
+template <typename T>
+struct __details_is_destructible : bool_constant<__is_destructible(T)> {};
+
+template <typename T>
+using is_destructible = __details_is_destructible<T>;
+
+template <typename T>
+constexpr bool is_destructible_v = is_destructible<T>::value;
+
 #endif
 }
 
@@ -374,6 +403,18 @@ static_assert(std::is_abstract_v<int&>);
 // expected-note@-1 {{because it is a reference type}} \
 // expected-note@-1 {{because it is not a struct or class type}}
 
+static_assert(std::is_destructible<int>::value);
+
+static_assert(std::is_destructible<void>::value);
+// expected-error-re@-1 {{static assertion failed due to requirement 'std::{{.*}}is_destructible<void>::value'}} \
+// expected-note@-1 {{'void' is not destructible}} \
+// expected-note@-1 {{because it is a cv void type}}
+
+static_assert(std::is_destructible_v<void>);
+// expected-error@-1 {{static assertion failed due to requirement 'std::is_destructible_v<void>'}} \
+// expected-note@-1 {{'void' is not destructible}} \
+// expected-note@-1 {{because it is a cv void type}}
+
 
 namespace test_namespace {
     using namespace std;
@@ -473,6 +514,17 @@ namespace test_namespace {
     // expected-note@-1 {{'int &' is not abstract}} \
     // expected-note@-1 {{because it is a reference type}} \
     // expected-note@-1 {{because it is not a struct or class type}}
+
+    static_assert(is_destructible<void>::value);
+    // expected-error-re@-1 {{static assertion failed due to requirement '{{.*}}is_destructible<void>::value'}} \
+    // expected-note@-1 {{'void' is not destructible}} \
+    // expected-note@-1 {{because it is a cv void type}}
+
+    static_assert(is_destructible_v<void>);
+    // expected-error@-1 {{static assertion failed due to requirement 'is_destructible_v<void>'}} \
+    // expected-note@-1 {{'void' is not destructible}} \
+    // expected-note@-1 {{because it is a cv void type}}
+
 }
 
 
@@ -518,6 +570,15 @@ concept C5 = std::is_aggregate_v<T>; // #concept10
 
 template <C5 T> void g5();  // #cand10
 
+template <typename T>
+requires std::is_destructible<T>::value void f6();  // #cand11
+
+template <typename T>
+concept C6 = std::is_destructible_v<T>; // #concept11
+
+template <C6 T> void g6();  // #cand12
+
+
 void test() {
     f<int&>();
     // expected-error@-1 {{no matching function for call to 'f'}} \
@@ -589,6 +650,21 @@ void test() {
     // expected-note@#concept10 {{because 'std::is_aggregate_v<void>' evaluated to false}} \
     // expected-note@#concept10 {{'void' is not aggregate}} \
     // expected-note@#concept10 {{because it is a cv void type}}
+
+    f6<void>();
+    // expected-error@-1 {{no matching function for call to 'f6'}} \
+    // expected-note@#cand11 {{candidate template ignored: constraints not satisfied [with T = void]}} \
+    // expected-note-re@#cand11 {{because '{{.*}}is_destructible<void>::value' evaluated to false}} \
+    // expected-note@#cand11 {{'void' is not destructible}} \
+    // expected-note@#cand11 {{because it is a cv void type}}
+
+    g6<void>();
+    // expected-error@-1 {{no matching function for call to 'g6'}} \
+    // expected-note@#cand12 {{candidate template ignored: constraints not satisfied [with T = void]}} \
+    // expected-note@#cand12 {{because 'void' does not satisfy 'C6'}} \
+    // expected-note@#concept11 {{because 'std::is_destructible_v<void>' evaluated to false}} \
+    // expected-note@#concept11 {{'void' is not destructible}} \
+    // expected-note@#concept11 {{because it is a cv void type}}
 }
 }
 

clang/test/SemaCXX/type-traits-unsatisfied-diags.cpp

@@ -1052,3 +1052,52 @@ static_assert(__is_abstract(U));
 // expected-note@-1 {{because it is not a struct or class type}}
 
 }
+namespace destructible {
+
+struct Incomplete; // expected-note {{forward declaration of 'destructible::Incomplete'}}
+static_assert(__is_destructible(Incomplete));
+// expected-error@-1 {{incomplete type 'Incomplete' used in type trait expression}}
+
+static_assert(__is_destructible(void));
+// expected-error@-1 {{static assertion failed due to requirement '__is_destructible(void)'}} \
+// expected-note@-1 {{'void' is not destructible}} \
+// expected-note@-1 {{because it is a cv void type}}
+
+using F = void();
+static_assert(__is_destructible(F));
+// expected-error@-1 {{static assertion failed due to requirement '__is_destructible(void ())'}} \
+// expected-note@-1 {{'void ()' is not destructible}} \
+// expected-note@-1 {{because it is a function type}}
+
+using Ref = int&;
+static_assert(__is_destructible(Ref)); // no diagnostics (true)
+
+struct DeletedDtor { // #d-DeletedDtor
+  ~DeletedDtor() = delete;
+};
+static_assert(__is_destructible(DeletedDtor));
+// expected-error@-1 {{static assertion failed due to requirement '__is_destructible(destructible::DeletedDtor)'}} \
+// expected-note@-1 {{'destructible::DeletedDtor' is not destructible}} \
+// expected-note@-1 {{because it has a deleted destructor}}
+
+struct PrivateDtor { // #d-PrivateDtor
+private:
+  ~PrivateDtor(); // #d-PrivateDtor-dtor
+};
+static_assert(__is_destructible(PrivateDtor));
+// expected-error@-1 {{static assertion failed due to requirement '__is_destructible(destructible::PrivateDtor)'}} \
+// expected-note@-1 {{'destructible::PrivateDtor' is not destructible}} \
+// expected-note@-1 {{because it has a private destructor}}
+
+struct BaseInaccessible { // #d-BaseInacc
+private:
+  ~BaseInaccessible(); // #d-BaseInacc-dtor
+};
+
+struct DerivedFromInaccessible : BaseInaccessible {}; // #d-DerivedInacc
+static_assert(__is_destructible(DerivedFromInaccessible));
+// expected-error@-1 {{static assertion failed due to requirement '__is_destructible(destructible::DerivedFromInaccessible)'}} \
+// expected-note@-1 {{'destructible::DerivedFromInaccessible' is not destructible}} \
+// expected-note@-1 {{because it has a deleted destructor}}
+
+}