Internal compiler warning: found a statement without source information.

[brucelynnzkm]

Hi, all. When i am trying to compile the following code,
//////////////////////////////////code_start//////////////////////////////////////////
struct record {
field[32] rec;
}

def updateRec(record mut states, u32 rec, field value) -> record {
states.rec[rec] = value;
return states;
}

def main(record mut states, u32 rec, field value) -> record{
return updateRec(states, rec, value);
}
///////////////////////////code end///////////////////////////////////////////////////

i got the following warnings:

Internal compiler warning: found a statement without source information. Please open an issue https://github.com/Zokrates/ZoKrates/issues/new?template=bug_report.md

how can i fix the warning? thanks.