Implement C23 _Static_assert without message (#440)

Co-authored-by: vit9696 <vit9696@users.noreply.github.com>

5 files changed, 16 insertions, 4 deletions

diff --git a/pycparser/c_generator.py b/pycparser/c_generator.py
index fdfe589..bbf1dd1 100644
--- a/pycparser/c_generator.py
+++ b/pycparser/c_generator.py
@@ -292,8 +292,9 @@ class CGenerator(object):
     def visit_StaticAssert(self, n):
         s = '_Static_assert('
         s += self.visit(n.cond)
-        s += ','
-        s += self.visit(n.message)
+        if n.message:
+            s += ','
+            s += self.visit(n.message)
         s += ')'
         return s
 
diff --git a/pycparser/c_parser.py b/pycparser/c_parser.py
index 61e4471..1be11a4 100644
--- a/pycparser/c_parser.py
+++ b/pycparser/c_parser.py
@@ -560,8 +560,12 @@ class CParser(PLYParser):
 
     def p_static_assert_declaration(self, p):
         """ static_assert           : _STATIC_ASSERT LPAREN constant_expression COMMA unified_string_literal RPAREN
+                                    | _STATIC_ASSERT LPAREN constant_expression RPAREN
         """
-        p[0] = [c_ast.StaticAssert(p[3], p[5], self._token_coord(p, 1))]
+        if len(p) == 5:
+            p[0] = [c_ast.StaticAssert(p[3], None, self._token_coord(p, 1))]
+        else:
+            p[0] = [c_ast.StaticAssert(p[3], p[5], self._token_coord(p, 1))]
 
     def p_pp_directive(self, p):
         """ pp_directive  : PPHASH
diff --git a/tests/c_files/c11.c b/tests/c_files/c11.c
index 1c7ec08..ff11162 100644
--- a/tests/c_files/c11.c
+++ b/tests/c_files/c11.c
@@ -33,6 +33,7 @@ _Noreturn void func(void)
 int main()
 {
   _Static_assert(sizeof(flag) == sizeof(flag2), "Unexpected size difference");
+  _Static_assert(sizeof(flag) == sizeof(flag2));
   static_assert(sizeof(flag) == sizeof(flag2), "Unexpected size difference");
   static_assert(sizeof(flag) == sizeof(flag3), "Unexpected size difference");
   static_assert(sizeof(flag) == sizeof(flag4), "Unexpected size difference");
diff --git a/tests/test_c_generator.py b/tests/test_c_generator.py
index a855e0b..4436a43 100644
--- a/tests/test_c_generator.py
+++ b/tests/test_c_generator.py
@@ -458,6 +458,7 @@ class TestCtoC(unittest.TestCase):
     def test_static_assert(self):
         self._assert_ctoc_correct('_Static_assert(sizeof(int) == sizeof(int), "123");')
         self._assert_ctoc_correct('int main() { _Static_assert(sizeof(int) == sizeof(int), "123"); } ')
+        self._assert_ctoc_correct('_Static_assert(sizeof(int) == sizeof(int));')
 
     def test_reduce_parentheses_binaryops(self):
         c1 = 'int x = a + b + c + d;';
diff --git a/tests/test_c_parser.py b/tests/test_c_parser.py
index 5b9d916..e83bd7d 100755
--- a/tests/test_c_parser.py
+++ b/tests/test_c_parser.py
@@ -43,7 +43,10 @@ def expand_decl(decl):
     elif typ == Alignas:
         return ['Alignas', expand_init(decl.alignment)]
     elif typ == StaticAssert:
-        return ['StaticAssert', decl.cond.value, decl.message.value]
+        if decl.message:
+            return ['StaticAssert', decl.cond.value, decl.message.value]
+        else:
+            return ['StaticAssert', decl.cond.value]
     else:
         nested = expand_decl(decl.type)
 
@@ -1644,11 +1647,13 @@ class TestCParser_fundamentals(TestCParser_base):
         int factorial(int p)
         {
             _Static_assert(2, "456");
+            _Static_assert(3);
         }
         ''')
 
         self.assertEqual(expand_decl(f1.ext[0]), ['StaticAssert', '1', '"123"'])
         self.assertEqual(expand_decl(f1.ext[1].body.block_items[0]), ['StaticAssert', '2', '"456"'])
+        self.assertEqual(expand_decl(f1.ext[1].body.block_items[2]), ['StaticAssert', '3'])
 
     def test_unified_string_literals(self):
         # simple string, for reference