[lazerg]

ReflectionEnumUnitCase and ReflectionEnumBackedCase only checked the constant in their own constructors, after ReflectionClassConstant::__construct() had already stored it. A subclass calling ReflectionClassConstant::__construct() directly skipped those checks, and so did a failed second __construct() call, which left the new constant in place. getBackingValue() then crashed, and getEnum()/getValue() returned the wrong types. The checks now live in ReflectionClassConstant::__construct() itself, keyed on the object's class, and run before anything is stored.

Fixes GH-25340

[ndossche]

getBackingValue is likely not the only method assuming that we're actually operating on a backed enum, this would need to be blocked another way I presume.