bls12_381 left shift bug in wasm (bellman)

[dark64]

Description

panicked at 'attempt to shift left with overflow', 
/home/darko/.cargo/registry/src/github.com-1ecc6299db9ec823/bellman_ce-0.3.5/src/domain.rs:64:26

The issue seems to be in the following line:

let max_degree = (1 << E::Fr::S) - 1;

where S for bls12_381 is 32. This happens when running setup in wasm, which is a 32-bit environment.

Possible solutions

• Fork bellman and resolve the issue
• Or remove support for bls12_381 (when using bellman) in zokrates-js