Function func_for 

pub fn func_for(
    source: &Func,
    names: &mut Interner,
    selector: &'static Selector,
    conv: &'static CallRegs,
    elsewhere: &Elsewhere,
    debug: bool,
) -> Result<Lowered, Unsupported>

func, for a build that says whether it writes debugging information. Without it the walk leaves out which value each declaration holds on the way into each block, since that is read only for the debugging information.

Errors

The same as func.