[clang] Add tests for CWG issues regarding completeness of types (#92113)

Endilll · web-flow · commit d542eb7aa830 · 2024-05-15T23:12:02.000+04:00
This patch covers the following Core issues: [CWG930](https://cplusplus.github.io/CWG/issues/930.html) "`alignof` with incomplete array type" [CWG1110](https://cplusplus.github.io/CWG/issues/1110.html) "Incomplete return type should be allowed in `decltype` operand" [CWG1340](https://cplusplus.github.io/CWG/issues/1340.html) "Complete type in member pointer expressions" [CWG1352](https://cplusplus.github.io/CWG/issues/1352.html) "Inconsistent class scope and completeness rules" [CWG1458](https://cplusplus.github.io/CWG/issues/1458.html) "Address of incomplete type vs `operator&()`" [CWG1824](https://cplusplus.github.io/CWG/issues/1824.html) "Completeness of return type vs point of instantiation" [CWG1832](https://cplusplus.github.io/CWG/issues/1832.html) "Casting to incomplete enumeration" [CWG2304](https://cplusplus.github.io/CWG/issues/2304.html) "Incomplete type vs overload resolution" [CWG2310](https://cplusplus.github.io/CWG/issues/2310.html) "Type completeness and derived-to-base pointer conversions" [CWG2430](https://cplusplus.github.io/CWG/issues/2430.html) "Completeness of return and parameter types of member functions" [CWG2512](https://cplusplus.github.io/CWG/issues/2512.html) "`typeid` and incomplete class types" [CWG2630](https://cplusplus.github.io/CWG/issues/2630.html) "Syntactic specification of class completeness" [CWG2718](https://cplusplus.github.io/CWG/issues/2718.html) "Type completeness for derived-to-base conversions" [CWG2857](https://cplusplus.github.io/CWG/issues/2857.html) "Argument-dependent lookup with incomplete class types" Current wording for CWG1110 came from [P0135R1](https://wg21.link/p0135R1) "Wording for guaranteed copy elision through simplified value categories". As a drive-by fix, I fixed incorrect status of CWG1815, test for which was added in #87933. CC @yronglin
diff --git a/clang/test/CXX/drs/cwg11xx.cpp b/clang/test/CXX/drs/cwg11xx.cpp
@@ -4,6 +4,21 @@
 // RUN: %clang_cc1 -std=c++17 %s -verify=expected -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++2a %s -verify=expected -fexceptions -fcxx-exceptions -pedantic-errors
 
+namespace cwg1110 { // cwg1110: 3.1
+#if __cplusplus >= 201103L
+template <typename T>
+T return_T();
+
+struct A;
+
+template <typename>
+struct B;
+
+decltype(return_T<A>())* a;
+decltype(return_T<B<int>>())* b;
+#endif
+} // namespace cwg1110
+
 namespace cwg1111 { // cwg1111: 3.2
 namespace example1 {
 template <typename> struct set; // #cwg1111-struct-set
diff --git a/clang/test/CXX/drs/cwg13xx.cpp b/clang/test/CXX/drs/cwg13xx.cpp
@@ -306,6 +306,18 @@ namespace cwg1330 { // cwg1330: 4 c++11
 
 // cwg1334: sup 1719
 
+namespace cwg1340 { // cwg1340: 2.9
+struct A;
+struct B;
+
+void f(B* a, A B::* p) {
+  (*a).*p;
+  // expected-warning@-1 {{expression result unused}}
+  a->*p;
+  // expected-warning@-1 {{expression result unused}}
+}
+} // namespace cwg1340
+
 namespace cwg1341 { // cwg1341: sup P0683R1
 #if __cplusplus >= 202002L
 int a;
@@ -451,6 +463,25 @@ static_assert(!__is_nothrow_constructible(D4, int), "");
 #endif
 } // namespace cwg1350
 
+namespace cwg1352 { // cwg1352: 3.0
+struct A {
+#if __cplusplus >= 201103L
+  int a = sizeof(A);
+#endif
+  void f(int b = sizeof(A));
+};
+
+template <typename T>
+struct B {
+#if __cplusplus >= 201103L
+  int a = sizeof(B) + sizeof(T);
+#endif
+  void f(int b = sizeof(B) + sizeof(T));
+};
+
+template class B<int>;
+} // namespace cwg1352
+
 namespace cwg1358 { // cwg1358: 3.1
 #if __cplusplus >= 201103L
   struct Lit { constexpr operator int() const { return 0; } };
diff --git a/clang/test/CXX/drs/cwg14xx.cpp b/clang/test/CXX/drs/cwg14xx.cpp
@@ -86,6 +86,23 @@ struct A {
 };
 }
 
+namespace cwg1458 { // cwg1458: 3.1
+#if __cplusplus >= 201103L
+struct A;
+
+void f() {
+  constexpr A* a = nullptr;
+  constexpr int p = &*a;
+  // expected-error@-1 {{cannot initialize a variable of type 'const int' with an rvalue of type 'A *'}}
+  constexpr A *p2 = &*a;
+}
+
+struct A {
+  int operator&();
+};
+#endif
+} // namespace cwg1458
+
 namespace cwg1460 { // cwg1460: 3.5
 #if __cplusplus >= 201103L
   namespace DRExample {
diff --git a/clang/test/CXX/drs/cwg18xx.cpp b/clang/test/CXX/drs/cwg18xx.cpp
@@ -206,7 +206,7 @@ namespace cwg1814 { // cwg1814: yes
 #endif
 }
 
-namespace cwg1815 { // cwg1815: yes
+namespace cwg1815 { // cwg1815: 19
 #if __cplusplus >= 201402L
   struct A { int &&r = 0; };
   A a = {};
@@ -303,6 +303,32 @@ namespace cwg1822 { // cwg1822: yes
 #endif
 }
 
+namespace cwg1824 { // cwg1824: 2.7
+template<typename T>
+struct A {
+  T t;
+};
+
+struct S {
+  A<S> f() { return A<S>(); }
+};
+} // namespace cwg1824
+
+namespace cwg1832 { // cwg1832: 3.0
+enum E { // #cwg1832-E
+  a = static_cast<int>(static_cast<E>(0))
+  // expected-error@-1 {{'E' is an incomplete type}}
+  //   expected-note@#cwg1832-E {{definition of 'cwg1832::E' is not complete until the closing '}'}}
+};
+
+#if __cplusplus >= 201103L
+enum E2: decltype(static_cast<E2>(0), 0) {};
+// expected-error@-1 {{unknown type name 'E2'}}
+enum class E3: decltype(static_cast<E3>(0), 0) {};
+// expected-error@-1 {{unknown type name 'E3'}}
+#endif
+} // namespace cwg1832
+
 namespace cwg1837 { // cwg1837: 3.3
 #if __cplusplus >= 201103L
   template <typename T>
diff --git a/clang/test/CXX/drs/cwg23xx.cpp b/clang/test/CXX/drs/cwg23xx.cpp
@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 -std=c++98 %s -verify=expected -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
-// RUN: %clang_cc1 -std=c++11 %s -verify=expected,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
-// RUN: %clang_cc1 -std=c++14 %s -verify=expected,since-cxx11,since-cxx14 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 %s -verify=expected,cxx11-14,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -std=c++14 %s -verify=expected,cxx11-14,since-cxx11,since-cxx14 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
 // RUN: %clang_cc1 -std=c++17 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
 // RUN: %clang_cc1 -std=c++20 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
 // RUN: %clang_cc1 -std=c++23 %s -verify=expected,since-cxx11,since-cxx14,since-cxx17,since-cxx20 -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s
@@ -47,6 +47,50 @@ void g() {
 } // namespace cwg2303
 #endif
 
+namespace cwg2304 { // cwg2304: 2.8
+template<typename T> void foo(T, int);
+template<typename T> void foo(T&, ...);
+struct Q; // #cwg2304-Q
+void fn1(Q &data_vectors) {
+  foo(data_vectors, 0);
+  // expected-error@-1 {{argument type 'cwg2304::Q' is incomplete}}
+  //   expected-note@#cwg2304-Q {{forward declaration of 'cwg2304::Q'}}
+}
+} // namespace cwg2304
+
+namespace cwg2310 { // cwg2310: partial
+#if __cplusplus >= 201103L
+template<typename A, typename B>
+struct check_derived_from {
+  static A a;
+  // FIXME: all 3 examples should be rejected in all language modes.
+  // FIXME: we should test this in 98 mode.
+  // FIXME: we accept this when MSVC triple is used
+  static constexpr B *p = &a;
+#if !defined(_WIN32) || defined(__MINGW32__)
+  // cxx11-14-error@-2 {{cannot initialize a variable of type 'cwg2310::X *const' with an rvalue of type 'cwg2310::Z *'}}
+  //   cxx11-14-note@#cwg2310-X {{in instantiation of template class 'cwg2310::check_derived_from<cwg2310::Z, cwg2310::X>' requested here}}
+  // cxx11-14-error@-4 {{cannot initialize a variable of type 'cwg2310::Y *const' with an rvalue of type 'cwg2310::Z *'}}
+  //   cxx11-14-note@#cwg2310-Y {{in instantiation of template class 'cwg2310::check_derived_from<cwg2310::Z, cwg2310::Y>' requested here}}
+#endif
+};
+
+struct W {};
+struct X {};
+struct Y {};
+struct Z : W,
+  X, check_derived_from<Z, X>, // #cwg2310-X
+  check_derived_from<Z, Y>, Y  // #cwg2310-Y
+{  
+  // FIXME: It was properly rejected before, but we're crashing since Clang 11 in C++11 and C++14 modes.
+  //        See https://github.com/llvm/llvm-project/issues/59920
+#if __cplusplus >= 201703L
+  check_derived_from<Z, W> cdf;
+#endif
+};
+#endif
+} // namespace cwg2310
+
 // cwg2331: na
 // cwg2335 is in cwg2335.cxx
 
diff --git a/clang/test/CXX/drs/cwg24xx.cpp b/clang/test/CXX/drs/cwg24xx.cpp
@@ -45,6 +45,12 @@ void fallthrough(int n) {
 #endif
 }
 
+namespace cwg2430 { // cwg2430: 2.7
+struct S {
+  S f(S s) { return s; }
+};
+} // namespace cwg2430
+
 namespace cwg2450 { // cwg2450: 18
 #if __cplusplus >= 202302L
 struct S {int a;};
diff --git a/clang/test/CXX/drs/cwg25xx.cpp b/clang/test/CXX/drs/cwg25xx.cpp
@@ -6,12 +6,21 @@
 // RUN: %clang_cc1 -std=c++23 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx20,since-cxx23 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++2c -triple x86_64-unknown-unknown %s -verify=expected,since-cxx11,since-cxx20,since-cxx23 -fexceptions -fcxx-exceptions -pedantic-errors
 
-#if __cplusplus == 199711L
-// expected-no-diagnostics
-#endif
+namespace std {
+struct type_info{};
+} // namespace std
 
 // cwg2504 is in cwg2504.cpp
 
+namespace cwg2512 { // cwg2512: 2.7
+struct A; // #cwg2512-A
+void foo(A* p) {
+  typeid(*p);
+  // expected-error@-1 {{'typeid' of incomplete type 'A'}}
+  //   expected-note@#cwg2512-A {{forward declaration of 'cwg2512::A'}}
+}
+} // namespace cwg2512
+
 namespace cwg2516 { // cwg2516: 3.0
                    // NB: reusing 1482 test
 #if __cplusplus >= 201103L
diff --git a/clang/test/CXX/drs/cwg2630.cpp b/clang/test/CXX/drs/cwg2630.cpp
@@ -0,0 +1,23 @@
+// RUN: split-file --leading-lines %s %t
+// RUN: %clang_cc1 -std=c++20 -verify -emit-module-interface %t/module.cppm -o %t/module.pcm
+// RUN: %clang_cc1 -std=c++20 -verify -fmodule-file=A=%t/module.pcm %t/main.cpp
+// RUN: %clang_cc1 -std=c++23 -verify -emit-module-interface %t/module.cppm -o %t/module.pcm
+// RUN: %clang_cc1 -std=c++23 -verify -fmodule-file=A=%t/module.pcm %t/main.cpp
+// RUN: %clang_cc1 -std=c++2c -verify -emit-module-interface %t/module.cppm -o %t/module.pcm
+// RUN: %clang_cc1 -std=c++2c -verify -fmodule-file=A=%t/module.pcm %t/main.cpp
+
+//--- module.cppm
+// expected-no-diagnostics
+export module A;
+
+namespace cwg2630 {
+export class X {};
+} // namespace cwg2630
+
+//--- main.cpp
+// expected-no-diagnostics
+import A;
+
+namespace cwg2630 { // cwg2630: 9
+X x;
+} // namespace cwg2630
diff --git a/clang/test/CXX/drs/cwg26xx.cpp b/clang/test/CXX/drs/cwg26xx.cpp
@@ -49,6 +49,8 @@ void f() {
 #endif
 }
 
+// cwg2630 is in cwg2630.cpp
+
 namespace cwg2631 { // cwg2631: 16
 #if __cplusplus >= 202002L
   constexpr int g();
diff --git a/clang/test/CXX/drs/cwg27xx.cpp b/clang/test/CXX/drs/cwg27xx.cpp
@@ -6,9 +6,17 @@
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++23 -verify=expected,since-cxx23 %s
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -std=c++2c -verify=expected,since-cxx23,since-cxx26 %s
 
-#if __cplusplus <= 202002L
-// expected-no-diagnostics
-#endif
+namespace cwg2718 { // cwg2718: 2.7
+struct B {};
+struct D;
+
+void f(B b) {
+  static_cast<D&>(b);
+  // expected-error@-1 {{non-const lvalue reference to type 'D' cannot bind to a value of unrelated type 'B'}}
+}
+
+struct D : B {};
+} // namespace cwg2718
 
 namespace cwg2759 { // cwg2759: 19
 #if __cplusplus >= 201103L
diff --git a/clang/test/CXX/drs/cwg28xx.cpp b/clang/test/CXX/drs/cwg28xx.cpp
@@ -6,10 +6,6 @@
 // RUN: %clang_cc1 -std=c++23 -verify=expected,since-cxx20,since-cxx23 %s
 // RUN: %clang_cc1 -std=c++2c -verify=expected,since-cxx20,since-cxx23,since-cxx26 %s
 
-#if __cplusplus < 202002L
-// expected-no-diagnostics
-#endif
-
 namespace cwg2819 { // cwg2819: 19 tentatively ready 2023-12-01
 #if __cpp_constexpr >= 202306L
   constexpr void* p = nullptr;
@@ -67,6 +63,30 @@ void B<int>::g() requires true;
 
 } // namespace cwg2847
 
+namespace cwg2857 { // cwg2857: no
+struct A {};
+template <typename>
+struct D;
+namespace N {
+  struct B {};
+  void adl_only(A*, D<int>*); // #cwg2857-adl_only
+}
+
+void f(A* a, D<int>* d) {
+  adl_only(a, d);
+  // expected-error@-1 {{use of undeclared identifier 'adl_only'; did you mean 'N::adl_only'?}}
+  //   expected-note@#cwg2857-adl_only {{'N::adl_only' declared here}}
+}
+
+#if __cplusplus >= 201103L
+template <typename>
+struct D : N::B {
+  // FIXME: ADL shouldn't associate it's base B and N since D is not complete here
+  decltype(adl_only((A*) nullptr, (D*) nullptr)) f;
+};
+#endif
+} // namespace cwg2857
+
 namespace cwg2858 { // cwg2858: 19 tentatively ready 2024-04-05
 
 #if __cplusplus > 202302L
diff --git a/clang/test/CXX/drs/cwg9xx.cpp b/clang/test/CXX/drs/cwg9xx.cpp
@@ -14,6 +14,13 @@ namespace std {
   };
 }
 
+namespace cwg930 { // cwg930: 2.7
+#if __cplusplus >= 201103L
+static_assert(alignof(int[]) == alignof(int), "");
+static_assert(alignof(int[][2]) == alignof(int[2]), "");
+#endif
+} // namespace cwg930
+
 namespace cwg948 { // cwg948: 3.7
 #if __cplusplus >= 201103L
   class A {
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html

Original file line number	Diff line number	Diff line change
`@@ -49,6 +49,8 @@ void f() {`
`49`	`49`	`#endif`
`50`	`50`	`}`
`51`	`51`
	`52`	`+// cwg2630 is in cwg2630.cpp`
	`53`	`+`
`52`	`54`	`namespace cwg2631 { // cwg2631: 16`
`53`	`55`	`#if __cplusplus >= 202002L`
`54`	`56`	`constexpr int g();`