seesymfony/symfony#27917 +symfony/symfony#12312

https://symfony.com/doc/current/validation/custom_constraint.html

instead of

if (!is_string($value)) {-    throw new UnexpectedTypeException($value, 'string');+    throw new UnexpectedValueException($value, 'string');}

This will cause a violation to be raised instead.

The"string" value is used withThis value should be of type {{ type }}., thus should be translator friendly. E.g. core uses phpdoc notation to avoid any grammar being used here (string|int instead ofstring or integer andSome&Other instead ofSome and Other).