llvmbot wrote:

<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: cor3ntin (cor3ntin)

<details>
<summary>Changes</summary>

- Support non-member functions and callable objects for size and data(). We 
previously tried to (badly) pick the best overload ourselves, in a way that 
would only support member functions. We now leave clamg construct an unresolved 
member expression and call that, properly performing overload resolution with 
callable objects and static functions, cojnsistent with the logic for `get` 
calls for structured bindings.
- Support UDLs as message expression.
- Add tests and mark CWG2798 as resolved

---
Full diff: https://github.com/llvm/llvm-project/pull/73234.diff


6 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+3) 
- (modified) clang/lib/Parse/ParseDeclCXX.cpp (+1-1) 
- (modified) clang/lib/Sema/SemaDeclCXX.cpp (+3-21) 
- (added) clang/test/CXX/drs/dr27xx.cpp (+30) 
- (modified) clang/test/SemaCXX/static-assert-cxx26.cpp (+44-10) 
- (modified) clang/www/cxx_dr_status.html (+1-1) 


``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7e2c990d03e7f27..5a8e63be1258a28 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -617,6 +617,9 @@ Bug Fixes in This Version
 - Fix crash during code generation of C++ coroutine initial suspend when the 
return
   type of await_resume is not trivially destructible.
   Fixes (`#63803 <https://github.com/llvm/llvm-project/issues/63803>`_)
+- Fix crash when the object used as a ``static_asssert`` message has ``size`` 
or ``data`` members
+  which are not member functions.
+- Support UDLs in ``static_asssert`` message.
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index d9125955fda2783..910112ecae964cc 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -1023,7 +1023,7 @@ Decl *Parser::ParseStaticAssertDeclaration(SourceLocation 
&DeclEnd) {
         const Token &T = GetLookAheadToken(I);
         if (T.is(tok::r_paren))
           break;
-        if (!tokenIsLikeStringLiteral(T, getLangOpts())) {
+        if (!tokenIsLikeStringLiteral(T, getLangOpts()) || T.hasUDSuffix()) {
           ParseAsExpression = true;
           break;
         }
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 3688192e6cbe5c5..01e2be3a45be85a 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -17291,33 +17291,15 @@ bool Sema::EvaluateStaticAssertMessageAsString(Expr 
*Message,
 
   auto FindMember = [&](StringRef Member, bool &Empty,
                         bool Diag = false) -> std::optional<LookupResult> {
-    QualType ObjectType = Message->getType();
-    Expr::Classification ObjectClassification =
-        Message->Classify(getASTContext());
-
     DeclarationName DN = PP.getIdentifierInfo(Member);
     LookupResult MemberLookup(*this, DN, Loc, Sema::LookupMemberName);
     LookupQualifiedName(MemberLookup, RD);
     Empty = MemberLookup.empty();
     OverloadCandidateSet Candidates(MemberLookup.getNameLoc(),
                                     OverloadCandidateSet::CSK_Normal);
-    for (NamedDecl *D : MemberLookup) {
-      AddMethodCandidate(DeclAccessPair::make(D, D->getAccess()), ObjectType,
-                         ObjectClassification, /*Args=*/{}, Candidates);
-    }
-    OverloadCandidateSet::iterator Best;
-    switch (Candidates.BestViableFunction(*this, Loc, Best)) {
-    case OR_Success:
-      return std::move(MemberLookup);
-    default:
-      if (Diag)
-        Candidates.NoteCandidates(
-            PartialDiagnosticAt(
-                Loc, PDiag(diag::err_static_assert_invalid_mem_fn_ret_ty)
-                         << (Member == "data")),
-            *this, OCD_AllCandidates, /*Args=*/{});
-    }
-    return std::nullopt;
+    if(MemberLookup.empty())
+      return std::nullopt;
+    return MemberLookup;
   };
 
   bool SizeNotFound, DataNotFound;
diff --git a/clang/test/CXX/drs/dr27xx.cpp b/clang/test/CXX/drs/dr27xx.cpp
new file mode 100644
index 000000000000000..f17726eb045f933
--- /dev/null
+++ b/clang/test/CXX/drs/dr27xx.cpp
@@ -0,0 +1,30 @@
+// RUN: %clang_cc1 -std=c++2c -verify %s
+
+namespace dr2798 { // dr2798: 17 drafting
+#if __cpp_static_assert >= 202306
+struct string {
+    constexpr string() {
+        data_ = new char[6]();
+        __builtin_memcpy(data_, "Hello", 5);
+        data_[5] = 0;
+    }
+    constexpr ~string() {
+        delete[] data_;
+    }
+    constexpr unsigned long size() const {
+        return 5;
+    };
+    constexpr const char* data() const {
+        return data_;
+    }
+
+    char* data_;
+};
+struct X {
+    string s;
+};
+consteval X f() { return {}; }
+
+static_assert(false, f().s); // expected-error {{static assertion failed: 
Hello}}
+#endif
+}
diff --git a/clang/test/SemaCXX/static-assert-cxx26.cpp 
b/clang/test/SemaCXX/static-assert-cxx26.cpp
index b19aac6cabd1324..f4ede74f9214a44 100644
--- a/clang/test/SemaCXX/static-assert-cxx26.cpp
+++ b/clang/test/SemaCXX/static-assert-cxx26.cpp
@@ -179,18 +179,20 @@ static_assert(false, Message{}); // expected-error 
{{static assertion failed: He
 }
 
 struct MessageInvalidSize {
-    constexpr auto size(int) const; // expected-note {{candidate function not 
viable: requires 1 argument, but 0 were provided}}
-    constexpr auto data() const;
+    constexpr unsigned long size(int) const; // expected-note {{'size' 
declared here}}
+    constexpr const char* data() const;
 };
 struct MessageInvalidData {
-    constexpr auto size() const;
-    constexpr auto data(int) const; // expected-note {{candidate function not 
viable: requires 1 argument, but 0 were provided}}
+    constexpr unsigned long size() const;
+    constexpr const char* data(int) const; // expected-note {{'data' declared 
here}}
 };
 
 static_assert(false, MessageInvalidSize{});  // expected-error {{static 
assertion failed}} \
-                                             // expected-error {{the message 
in a static assertion must have a 'size()' member function returning an object 
convertible to 'std::size_t'}}
+                                             // expected-error {{the message 
in a static assertion must have a 'size()' member function returning an object 
convertible to 'std::size_t'}} \
+                                             // expected-error {{too few 
arguments to function call, expected 1, have 0}}
 static_assert(false, MessageInvalidData{});  // expected-error {{static 
assertion failed}} \
-                                             // expected-error {{the message 
in a static assertion must have a 'data()' member function returning an object 
convertible to 'const char *'}}
+                                             // expected-error {{the message 
in a static assertion must have a 'data()' member function returning an object 
convertible to 'const char *'}} \
+                                             // expected-error {{too few 
arguments to function call, expected 1, have 0}}
 
 struct NonConstMembers {
     constexpr int size() {
@@ -227,14 +229,14 @@ static_assert(false, Variadic{}); // expected-error 
{{static assertion failed: O
 
 template <typename T>
 struct DeleteAndRequires {
-    constexpr int size() = delete; // expected-note {{candidate function has 
been explicitly deleted}}
-    constexpr const char* data() requires false; // expected-note {{candidate 
function not viable: constraints not satisfied}} \
-                                                 // expected-note {{because 
'false' evaluated to false}}
+    constexpr int size() = delete; // expected-note {{'size' has been 
explicitly marked deleted here}}
+    constexpr const char* data() requires false; // expected-note {{because 
'false' evaluated to false}}
 };
 static_assert(false, DeleteAndRequires<void>{});
 // expected-error@-1 {{static assertion failed}} \
 // expected-error@-1 {{the message in a static assertion must have a 'size()' 
member function returning an object convertible to 'std::size_t'}}\
-// expected-error@-1 {{the message in a static assertion must have a 'data()' 
member function returning an object convertible to 'const char *'}}
+// expected-error@-1 {{invalid reference to function 'data': constraints not 
satisfied}} \
+// expected-error@-1 {{attempt to use a deleted function}}
 
 class Private {
     constexpr int size(int i = 0) { // expected-note {{implicitly declared 
private here}}
@@ -294,6 +296,9 @@ struct Frobble {
   constexpr const char *data() const { return "hello"; }
 };
 
+constexpr Frobble operator ""_myd (const char *, unsigned long) { return 
Frobble{}; }
+static_assert (false, "foo"_myd); // expected-error {{static assertion failed: 
hello}}
+
 Good<Frobble> a; // expected-note {{in instantiation}}
 Bad<int> b; // expected-note {{in instantiation}}
 
@@ -307,3 +312,32 @@ static_assert((char8_t)-128 == (char8_t)-123, ""); // 
expected-error {{failed}}
 static_assert((char16_t)0xFEFF == (char16_t)0xDB93, ""); // expected-error 
{{failed}} \
                                                          // expected-note 
{{evaluates to 'u'' (0xFEFF, 65279) == u'\xDB93' (0xDB93, 56211)'}}
 }
+
+struct Static {
+  static constexpr int size() { return 5; }
+  static constexpr const char *data() { return "hello"; }
+};
+static_assert(false, Static{}); // expected-error {{static assertion failed: 
hello}}
+
+struct Data {
+    unsigned long size = 0;
+    const char* data = "hello";
+};
+static_assert(false, Data{}); // expected-error {{called object type 'unsigned 
long' is not a function or function pointer}} \
+                              // expected-error {{called object type 'const 
char *' is not a function or function pointer}} \
+                              // expected-error {{the message in a static 
assertion must have a 'size()' member function returning an object convertible 
to 'std::size_t'}} \
+                              // expected-error {{static assertion failed}}
+
+struct Callable {
+    struct {
+        constexpr auto operator()() const {
+            return 5;
+        };
+    } size;
+    struct {
+        constexpr auto operator()() const {
+            return "hello";
+        };
+    } data;
+};
+static_assert(false, Callable{}); // expected-error {{static assertion failed: 
hello}}
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index e711b2173d191c1..266891a2e373090 100755
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -7145,7 +7145,7 @@ <h2 id="cxxdr">C++ defect report implementation 
status</h2>
     <td><a 
href="https://cplusplus.github.io/CWG/issues/1223.html";>1223</a></td>
     <td>drafting</td>
     <td>Syntactic disambiguation and <I>trailing-return-type</I>s</td>
-    <td class="unreleased" align="center">Clang 17</td>
+    <td class="full" align="center">Clang 17</td>
   </tr>
   <tr id="1224">
     <td><a 
href="https://cplusplus.github.io/CWG/issues/1224.html";>1224</a></td>

``````````

</details>


https://github.com/llvm/llvm-project/pull/73234
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