Function compile_program_to_chips_returning 

pub fn compile_program_to_chips_returning(
    source: &str,
    target: &SpatialTarget,
    manifest: &TpManifest,
    results: &BTreeSet<String>,
) -> Result<ChipLowering, SpatialReject>

compile_program_to_chips for a program whose results are declared (see compile_program_to_spatial_returning): on each chip, a tensor only the next statement reads — no statement of any chip, no Show, no carried state, nothing results names — is forwarded.