Still need to support the method returning false in PHP <8

for a php version dependent return-type a DynamicFunctionReturnTypeExtension would be a better fit then a stub.
sorry, I just saw this comment right now.

we have a few of them in the codebase already for inspiration.

Yikes - as this codebase is so new to me, I'm struggling to know where to start. It looks like this is the first time a string function has made use of the DynamicReturnTypeExtension.

NativeReflectionEnumReturnDynamicReturnTypeExtension looks to be one of the simplest but I don't know what count_chars() needs for getClass()|isMethodSupported()|getTypeFromMethodCall() and all of this just to capture and also return false on PHP <8. 😮‍💨

• Is there much value when PHPStan 2 requires ^8.1?
• Is this PR no longer valid as is?

t looks like this is the first time a string function has made use of the DynamicReturnTypeExtension.

see e.g. https://github.com/phpstan/phpstan-src/blob/2.0.x/src/Type/Php/AbsFunctionDynamicReturnTypeExtension.php which is similar to what we need.

• Is there much value when PHPStan 2 requires ^8.1?

PHPStan 2.x will have min php version of 7.4.
8.1 is only used for development in the code-base but is downgraded for 7.4 compat on release.

• Is this PR no longer valid as is?

the test-cases are still useful

@staabm: thanks for your patience/guidance 🙏🏻

Thank you.