When using the Theta REPL, if you try to do any kind of assignment, even something as simple as x<Number> = 1, it will fail with a segmentation fault.

It seems that if you wrap the assignment in a capsule, that issue doesn't occur.

capsule Test { x<Number> = 1 }

The above code parses exactly as expected. The issue seems to stem somehow from how free-floating expressions are parsed within the REPL.