Function emit_write_aggregate_field

pub(crate) fn emit_write_aggregate_field(
    body: &mut InstrSeqBuilder<'_>,
    ctx: &LowerCtx<'_>,
    base_ptr_local: LocalId,
    base_ty: &Ty,
    field: &str,
    src_local: LocalId,
    src_ty: ValType,
) -> Result<(), LowerError>

Write one aggregate field from a runtime local.