# Objective
* The `SystemParam` derive internally uses tuples, which means it is constrained by the 16-field limit on `all_tuples`.
* The error message if you exceed this limit is abysmal.
* Supercedes #5965 -- this does the same thing, but is simpler.
## Solution
If any tuples have more than 16 fields, they are folded into tuples of tuples until they are under the 16-field limit.
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| .. | ||
| entity | ||
| query | ||
| schedule | ||
| storage | ||
| system | ||
| world | ||
| archetype.rs | ||
| bundle.rs | ||
| change_detection.rs | ||
| component.rs | ||
| event.rs | ||
| lib.rs | ||
| reflect.rs | ||