alias PSC = ParameterStorageClass;
alias PSCT = ParameterStorageClassTuple;

void fun1(return ref int){}
void fun2(return out int){}

PSCT!fun1 == (PSC.return_ | PSC.ref_) // false
PSCT!fun2 == (PSC.return_ | PSC.out_) // false

PSCT!fun1 == PSC.return_ // true
PSCT!fun2 == PSC.return_ // true

how to differentiate them?