Currently, trait methods are aliased will continue to use the
original function name. In a few places in the codebase, we will
try to look up the actual method name instead. However, this does
not work if an aliased method is used indirectly
(https://bugs.php.net/bug.php?id=69180).
I think it would be better to instead actually change the method
name to the alias. This is in principle easy: We have to allow
function_name to be changed even if op array is otherwise shared
(similar to static_variables). This means we need to addref/release
the function_name separately, but I don't think there is a
performance concern here (especially as everything is usually
interned).
There is a bit of complication in opcache, where we need to make
sure that the function name is released the correct number of times
(interning may overwrite the name in the original op_array, but we
need to release it as many times as the op_array is shared).
Fixes bug #69180.
Fixes bug #74939.
Closes GH-5226.
Specifically, this checks if there are trait aliases defined in the class scope
before attempting to dereference the first trait alias. This handles the case
where a trait alias was used in a child trait but no aliases exist in the
concrete class.
