RE2C version 4 emits warnings

[petk]

Description

The following code:

git clone https://github.com/skvadrik/re2c
cd re2c
git checkout 4.0.2
cmake -B build
cmake --build build -j

cd ../php-src
./buildconf
RE2C=../re2c/build/re2c ./configure
make

Resulted in this output:

ext/pdo/pdo_sql_parser.re:35:1: warning: control flow is undefined for strings that match '\x0', use default rule '*' [-Wundefined-control-flow]
ext/pdo_sqlite/sqlite_sql_parser.re:36:1: warning: control flow is undefined for strings that match '\x0', use default rule '*' [-Wundefined-control-flow]
Zend/zend_language_scanner.l:1816:19: warning: escape has no effect: '\*' [-Wuseless-escape]
Zend/zend_language_scanner.l:1820:19: warning: escape has no effect: '\*' [-Wuseless-escape]
Zend/zend_ini_scanner.l:355:13: warning: escape has no effect: '\.' [-Wuseless-escape]
Zend/zend_ini_scanner.l:355:32: warning: escape has no effect: '\.' [-Wuseless-escape]
Zend/zend_ini_scanner.l:362:32: warning: escape has no effect: '\[' [-Wuseless-escape]
Zend/zend_ini_scanner.l:364:11: warning: escape has no effect: '\[' [-Wuseless-escape]
Zend/zend_ini_scanner.l:661:66: warning: unreachable rule in condition 'ST_OFFSET' (shadowed by rule at line 606) [-Wunreachable-rules]
Zend/zend_ini_scanner.l:661:66: warning: unreachable rule in condition 'ST_SECTION_VALUE' (shadowed by rule at line 606) [-Wunreachable-rules]
...

But I expected output without RE2C specific warnings.

Probably all lexer-related files should be rechecked and updated a bit.

PHP Version

PHP 8.3

Operating System

Any

[cmb69]

Closing as duplicate of #17523, since the new issue contains more relevant information.

[bukka]

This is not completely a duplicate as it specifies some other warnings that we should fix.