Commented by: @dyemanov

I don't see this issue in the code. All built-in functions don't have declared parameter types/lengths, they accept whatever is passed. The problem is whether the argument can be converted to the expected datatype. RDB$ROLE_IN_USE expects a string of arbitrary length, I don't see any limit implied there.

Commented by: @AlexPeshkoff

When long role name is used RDB$ROLE_IN_USE incorrectly returns false even in a case RDB$ROLE_IN_USE(current_role)

Commented by: @AlexPeshkoff

There were 2 issues - first, varchar(32) in documentation, which was obviously wrong limit, Dmitry is right, built-in functions accept whatever is passed. But there was one more issue - case sensitivity. I've blindly uppercased role name what is definitely wrong - we may have roles with lower case letters, moreover, we may have SOMEROLE and SomeRole, and that will be 2 different roles.

The small problem with this function is that we can't use double quotes to mark names of case-sensitive roles - we should be able to accept strings returned by CURRENT_ROLE, values in RDB$ROLE_NAME field, and they all do not contain double quotes. Therefore the only working solution is to always enter role name case sensitive.