Fix #14256 syntaxError for C++23 lambda without parameter clause (#7953)

Author: chrchr-github

lib/tokenize.cpp

@@ -8920,7 +8920,7 @@ void Tokenizer::findGarbageCode() const
         if (Token::Match(tok, "!|~ %comp%") &&
             !(cpp && tok->strAt(1) == ">" && Token::simpleMatch(tok->tokAt(-1), "operator")))
             syntaxError(tok);
-        if (Token::Match(tok, "] %name%") && (!cpp || !(tok->tokAt(-1) && Token::simpleMatch(tok->tokAt(-2), "delete [")))) {
+        if (Token::Match(tok, "] %name%") && (!cpp || !(tok->tokAt(1)->isKeyword() || (tok->tokAt(-1) && Token::simpleMatch(tok->tokAt(-2), "delete ["))))) {
             if (tok->next()->isUpperCaseName())
                 unknownMacroError(tok->next());
             else

test/testtokenize.cpp

@@ -7994,6 +7994,12 @@ class TestTokenizer : public TestFixture {
                                              "int main() { \n"
                                              "    takesFunc([func = [](S s) { return s.c; }] {});\n"
                                              "}\n"));
+
+        ASSERT_NO_THROW(tokenizeAndStringify("void f() {\n" // #14256
+                                             "    int i = 0;\n"
+                                             "    auto x = [i] mutable {};\n"
+                                             "}\n"));
+
         ignore_errout();
     }
     void checkIfCppCast() {