[php-src] Issue #18838: Fuzzer `php-fuzz-execute` crashing testcase: Assertion `!(executor_globals.exception)' failed.

Issue: https://github.com/php/php-src/issues/18838 Author: gal1ium ### Description The following code: ```php <?php class Foo { public function __toString() { } } function test(string $foo = new Foo() > '') { var_dump($foo); } test(); ?> ``` Resulted in this output: ``` php-fuzz-execute: Zend/zend_vm_execute.h:4135: const zend_op *ZEND_INIT_FCALL_SPEC_CONST_HANDLER(zend_execute_data *, const zend_op *): Assertion `!(executor_globals.exception)' failed. ==732252== ERROR: libFuzzer: deadly signal ... #9 0x7f9e9117b7f2 in abort stdlib/abort.c:79:7 #10 0x7f9e9117b71a in __assert_fail_base assert/assert.c:94:3 #11 0x7f9e9118ce95 in __assert_fail assert/assert.c:103:3 #12 0xfdefc2 in ZEND_INIT_FCALL_SPEC_CONST_HANDLER /src/php-src/Zend/zend_vm_execute.h:4135:2 #13 0x12609fd in fuzzer_execute_ex /src/php-src/sapi/fuzzer/fuzzer-execute-common.h:59:12 #14 0xfdc7a9 in ZEND_DO_FCALL_SPEC_RETVAL_UNUSED_HANDLER /src/php-src/Zend/zend_vm_execute.h:1972:4 #15 0x12609fd in fuzzer_execute_ex /src/php-src/sapi/fuzzer/fuzzer-execute-common.h:59:12 #16 0xf39af4 in zend_execute /src/php-src/Zend/zend_vm_execute.h:64220:2 #17 0x12615cc in fuzzer_do_request_from_buffer /src/php-src/sapi/fuzzer/fuzzer-sapi.c:274:5 #18 0x126083f in LLVMFuzzerTestOneInput /src/php-src/sapi/fuzzer/fuzzer-execute.c:27:2 ``` ### PHP Version ```plain dbabbe180b157eeaac5002276667f1f56f0b4def 2025-06-10 22:35:56+0200 ``` ### Operating System _No response_