Function try_inlining

fn try_inlining<'tcx, I: Inliner<'tcx>>(
    inliner: &I,
    caller_body: &mut Body<'tcx>,
    callsite: &CallSite<'tcx>,
) -> Result<Range<BasicBlock>, &'static str>

Attempts to inline a callsite into the caller body. When successful returns basic blocks containing the inlined body. Otherwise returns an error describing why inlining didn’t take place.