message: missing undef check in brilck?
diff: @@ -353,6 +353,7 @@ function checkFunc(funcs: FuncEnv, func: bril.Function) {
  }
  // Gather up all the types of the local variables and all the label names.
  + if (func.instrs){
  for (let instr of func.instrs) {
  if ('dest' in instr) {
  addType(vars, instr.dest, instr.type, instr.pos);
  @@ -376,6 +377,7 @@ function checkFunc(funcs: FuncEnv, func: bril.Function) {
  }
  }
  }
  +}
  function checkProg(prog: bril.Program) {
  // Gather up function types.
  