The same rules are applied for properties that are defined in the class hierarchy. Thus, if the properties are compatible, a notice is issued, if not a fatal error occures.
Strict Standards: Notice and THello1 define the same property ($hello) in the composition of Notice. This might be incompatible, to improve maintainability consider using accessor methods in traits instead. Class was composed in %s on line %d
Fatal error: TraitsTest and THello1 define the same property ($hello) in the composition of TraitsTest. However, the definition differs and is considered incompatible. Class was composed in %s on line %d