[clang][NFC] Add CWG713 test; add example from CWG1584 test #100747

MitalAshok · 2024-07-26T13:56:49Z

https://cplusplus.github.io/CWG/issues/713.html
https://cplusplus.github.io/CWG/issues/1584.html

https://cplusplus.github.io/CWG/issues/713.html https://cplusplus.github.io/CWG/issues/1584.html

llvmbot · 2024-07-26T13:57:26Z

@llvm/pr-subscribers-clang

Author: Mital Ashok (MitalAshok)

Changes

https://cplusplus.github.io/CWG/issues/713.html
https://cplusplus.github.io/CWG/issues/1584.html

Full diff: https://github.com/llvm/llvm-project/pull/100747.diff

3 Files Affected:

(modified) clang/test/CXX/drs/cwg15xx.cpp (+31-17)
(modified) clang/test/CXX/drs/cwg7xx.cpp (+17-1)
(modified) clang/www/cxx_dr_status.html (+1-1)

diff --git a/clang/test/CXX/drs/cwg15xx.cpp b/clang/test/CXX/drs/cwg15xx.cpp
index 21a392a5141e3..961c25000111a 100644
--- a/clang/test/CXX/drs/cwg15xx.cpp
+++ b/clang/test/CXX/drs/cwg15xx.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify=expected -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify=expected,cxx98 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify=expected,cxx11-20,since-cxx11,cxx11-14 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown %s -verify=expected,cxx11-20,since-cxx11,cxx11-14,cxx14-17 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-unknown %s -verify=expected,cxx11-20,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
@@ -6,6 +6,11 @@
 // RUN: %clang_cc1 -std=c++23 -triple x86_64-unknown-unknown %s -verify=expected,since-cxx23,since-cxx20,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -std=c++2c -triple x86_64-unknown-unknown %s -verify=expected,since-cxx23,since-cxx20,since-cxx11,since-cxx17 -fexceptions -fcxx-exceptions -pedantic-errors
 
+#if __cplusplus == 199711L
+#define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
+// cxx98-error@-1 {{variadic macros are a C99 feature}}
+#endif
+
 namespace cwg1512 { // cwg1512: 4
   void f(char *p) {
     if (p > 0) {}
@@ -556,24 +561,33 @@ auto CWG1579_lambda_invalid = []() -> GenericMoveOnly<char> {
 } // end namespace cwg1579
 
 namespace cwg1584 { // cwg1584: 7 drafting 2015-05
-#if __cplusplus >= 201103L
-  // Deducing function types from cv-qualified types
-  template<typename T> void f(const T *); // #cwg1584-f
-  template<typename T> void g(T *, const T * = 0);
-  template<typename T> void h(T *) { T::error; }
-  // since-cxx11-error@-1 {{type 'void ()' cannot be used prior to '::' because it has no members}}
-  //   since-cxx11-note@#cwg1584-h {{in instantiation of function template specialization 'cwg1584::h<void ()>' requested here}}
-  template<typename T> void h(const T *);
-  void i() {
-    f(&i);
-    // since-cxx11-error@-1 {{no matching function for call to 'f'}}
-    //   since-cxx11-note@#cwg1584-f {{candidate template ignored: could not match 'const T *' against 'void (*)()'}}
-    g(&i);
-    h(&i); // #cwg1584-h
-  }
-#endif
+// Deducing function types from cv-qualified types
+template<typename T> void f(const T *); // #cwg1584-f
+template<typename T> void g(T *, const T * = 0);
+template<typename T> void h(T *) { T::error; }
+// expected-error@-1 {{type 'void ()' cannot be used prior to '::' because it has no members}}
+//   expected-note@#cwg1584-h {{in instantiation of function template specialization 'cwg1584::h<void ()>' requested here}}
+template<typename T> void h(const T *);
+void i() {
+  f(&i);
+  // expected-error@-1 {{no matching function for call to 'f'}}
+  //   expected-note@#cwg1584-f {{candidate template ignored: could not match 'const T *' against 'void (*)()'}}
+  g(&i);
+  h(&i); // #cwg1584-h
 }
 
+template<typename T> struct tuple_size {
+  static const bool is_primary = true;
+};
+template<typename T> struct tuple_size<T const> : tuple_size<T> {
+  static const bool is_primary = false;
+};
+
+tuple_size<void()> t;
+static_assert(tuple_size<void()>::is_primary, "");
+static_assert(tuple_size<void()const>::is_primary, "");
+} // namespace cwg1584
+
 namespace cwg1589 {   // cwg1589: 3.7 c++11
 #if __cplusplus >= 201103L
   // Ambiguous ranking of list-initialization sequences
diff --git a/clang/test/CXX/drs/cwg7xx.cpp b/clang/test/CXX/drs/cwg7xx.cpp
index 6d93e2948dadb..1e5d3c0873d8b 100644
--- a/clang/test/CXX/drs/cwg7xx.cpp
+++ b/clang/test/CXX/drs/cwg7xx.cpp
@@ -1,9 +1,14 @@
-// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++98 %s -verify=expected,cxx98-14,cxx98-11 -fexceptions -fcxx-exceptions -pedantic-errors
+// RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++98 %s -verify=expected,cxx98,cxx98-14,cxx98-11 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++11 %s -verify=expected,cxx98-14,cxx98-11,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++14 %s -verify=expected,cxx98-14,since-cxx14,since-cxx11,cxx14 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++17 %s -verify=expected,since-cxx14,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
 // RUN: %clang_cc1 -triple %itanium_abi_triple -std=c++2a %s -verify=expected,since-cxx14,since-cxx11 -fexceptions -fcxx-exceptions -pedantic-errors
 
+#if __cplusplus == 199711L
+#define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
+// cxx98-error@-1 {{variadic macros are a C99 feature}}
+#endif
+
 namespace cwg705 { // cwg705: yes
   namespace N {
     struct S {};
@@ -71,6 +76,17 @@ namespace cwg712 { // cwg712: partial
 #endif
 }
 
+namespace cwg713 { // cwg713: yes
+static_assert(!__is_const(void()const), "");
+static_assert(!__is_const(void()const volatile), "");
+static_assert(!__is_volatile(void()volatile), "");
+static_assert(!__is_volatile(void()const volatile), "");
+#if __cplusplus >= 201103L
+static_assert(!__is_const(void()const&), "");
+static_assert(!__is_volatile(void()volatile&), "");
+#endif
+} // namespace cwg713
+
 namespace cwg727 { // cwg727: partial
   struct A {
     template<typename T> struct C; // #cwg727-C
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 937f67981e296..3dd91be9ed9d3 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -4327,7 +4327,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2>
     <td><a href="https://cplusplus.github.io/CWG/issues/713.html">713</a></td>
     <td>CD2</td>
     <td>Unclear note about cv-qualified function types</td>
-    <td class="unknown" align="center">Unknown</td>
+    <td class="full" align="center">Yes</td>
   </tr>
   <tr id="714">
     <td><a href="https://cplusplus.github.io/CWG/issues/714.html">714</a></td>

MitalAshok · 2024-07-26T13:59:10Z

@Endilll The problem with the CWG713 test in Clang 18 was with parsing the type trait (#81298), they weren't actually considered const: https://godbolt.org/z/snde76brE

Also, I would think since the resolution is purely editorial (it just changes notes, nothing normative), it would be considered implemented in any clang version?

Endilll · 2024-07-26T14:35:33Z

Also, I would think since the resolution is purely editorial (it just changes notes, nothing normative), it would be considered implemented in any clang version?

The question "availability" answers is "What is the first Clang version that exhibits the correct behavior?", where the correct behavior is approximated by the test in our test suite. Because Clang 18 does not pass your CWG713 test, we can't claim that it implements this CWG issue as we understand it.

Endilll · 2024-07-26T15:16:01Z

clang/test/CXX/drs/cwg7xx.cpp

@@ -71,6 +76,17 @@ namespace cwg712 { // cwg712: partial
 #endif
 }

+namespace cwg713 { // cwg713: yes


Please check how just released Clang 19.1-rc1 handles this test, and choose between 19 and 20 accordingly.

MitalAshok · 2024-07-26T15:48:38Z

New test compiles down to clang 3.0 (except warnings for https://cplusplus.github.io/CWG/issues/547.html) but do not compile before that because of the lack of __is_const/__is_volatile type traits.

Function types with cv- qualifiers were added for Clang 2.5 in 22c40fa, where they already used a different field to hold the qualifiers (thus the function types were not considered const/volatile/__restrict themselves), so it should be okay to claim this was implemented in Clang 2.5?

Endilll · 2024-07-26T15:59:32Z

New test compiles down to clang 3.0 (except warnings for https://cplusplus.github.io/CWG/issues/547.html) but do not compile before that because of the lack of __is_const/__is_volatile type traits.

Function types with cv- qualifiers were added for Clang 2.5 in 22c40fa, where they already used a different field to hold the qualifiers (thus the function types were not considered const/volatile/__restrict themselves), so it should be okay to claim this was implemented in Clang 2.5?

Thank you for the analysis! Typically you don't need to dig that deep. Based on https://godbolt.org/z/n6oPdMT91, I think 3.1 is the correct availability here, but I can be persuaded for 3.0.

Clang 2.7 was the first one that by default provided C++ support without relying on GCC frontend, so I don't think it's meaningful to go further than that. (Clang 2.6 (assertions) on Compiler Explorer is patched to use internal C++ support, you can see for yourself how broken it was.)

MitalAshok · 2024-07-26T16:20:37Z

Based on https://godbolt.org/z/n6oPdMT91, I think 3.1 is the correct availability here, but I can be persuaded for 3.0.

The warnings are because of how the test is written, the tested behaviour ("function types are never const or volatile") is still true in Clang 3.0

) https://cplusplus.github.io/CWG/issues/713.html https://cplusplus.github.io/CWG/issues/1584.html

[clang][Tests][NFC] Add CWG713 test; add example from CWG1584 test

1ba0cbc

https://cplusplus.github.io/CWG/issues/713.html https://cplusplus.github.io/CWG/issues/1584.html

MitalAshok requested a review from Endilll as a code owner July 26, 2024 13:56

llvmbot added the clang Clang issues not falling into any other category label Jul 26, 2024

Endilll requested changes Jul 26, 2024

View reviewed changes

MitalAshok added 2 commits July 26, 2024 16:50

Make test work back up to Clang 3

3156001

Mark as Clang 2.5

f9f1264

MitalAshok force-pushed the cwg713-tests branch from 8cb011b to f9f1264 Compare July 26, 2024 15:50

2.5 -> 3.0

87dfb54

Endilll approved these changes Jul 26, 2024

View reviewed changes

MitalAshok changed the title ~~[clang][Tests][NFC] Add CWG713 test; add example from CWG1584 test~~ [clang][NFC] Add CWG713 test; add example from CWG1584 test Jul 31, 2024

cor3ntin merged commit 30e5d71 into llvm:main Aug 5, 2024
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banach-space pushed a commit to banach-space/llvm-project that referenced this pull request Aug 7, 2024

[clang][NFC] Add CWG713 test; add example from CWG1584 test (llvm#100747

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) https://cplusplus.github.io/CWG/issues/713.html https://cplusplus.github.io/CWG/issues/1584.html

kstoimenov pushed a commit to kstoimenov/llvm-project that referenced this pull request Aug 15, 2024

[clang][NFC] Add CWG713 test; add example from CWG1584 test (llvm#100747

f425a49

) https://cplusplus.github.io/CWG/issues/713.html https://cplusplus.github.io/CWG/issues/1584.html

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[clang][NFC] Add CWG713 test; add example from CWG1584 test #100747

[clang][NFC] Add CWG713 test; add example from CWG1584 test #100747

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[clang][NFC] Add CWG713 test; add example from CWG1584 test #100747

[clang][NFC] Add CWG713 test; add example from CWG1584 test #100747

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