%Error-IMPURE: t/t_func_impure_bad.v:11:9: Unsupported: External variable referenced by non-inlined function/task: 't.foo'
   11 |    task foo;
      |         ^~~
               t/t_func_impure_bad.v:13:7: ... Location of the external reference: 't.sig'
   13 |       sig = '1;
      |       ^~~
               ... For error description see https://verilator.org/warn/IMPURE?v=latest
%Error: Exiting due to