1367 extend does not require an "add" block The compiler accepts a file with an "extend" clause, that contains no "add", although the aldor user guide on page 120 states, that a post facto extension has to be of the form extend T : C == D where "D is a package providing implementations for the newly required exports". One might argue, that the compiler is supposed to accept extensions in the form of extend T : C if there are no additional implementations needed (as is the case in the provided file). Then on the other hand, the aldor user guide is once again faulty in a section. But then in turn, the compiler should really executable code, as the provided sample file segfaults. Indeed, there is obviously no checking of whether the extension is ok or not, because even a extend MachineInteger : DataStructureType (without any add) is ok, for the compiler (although producing segfaulting code). Anyways if the commented #include "algebra" is un-commented, then the example file compiles well and even does no longer segfault ! N.B.: This bug occurred with compiler version 1.0.1 as indicated. But upgrading to version 1.0.2 does not change the situation dk 2 /aldor.org/website/bugs/bugreport_1367/bugExtend1.as aldor -g interp bugExtend1.as 1.0.1 christian.aistleitner@gmx.at yes dk dk dk dk dk no no