- assoc on a vector bounds-checks the index (0..count); out-of-range/negative throw
- dissoc throws on non-maps (numbers/sequences/sets/scalars); nil ok; records/
sorted-maps/meta-maps still handled
- count throws on scalars (numbers/keywords/symbols/booleans/chars)
- subvec validates vector type and 0<=start<=end<=count
- numerator/denominator always throw (Jolt has no ratio type)
- min-key/max-key throw on no values
count 18/2; dissoc 19/3; assoc 36/6; subvec 26/3/5; numerator/denominator throw
cases pass. clojure-test-suite pass 3840->3864. spec: map/strictness (16). jpm test green.