It's a math culture thing. Names barely matter, relationships do. All math since junior high is about f(x), not function_of(variable_entity).
It's very disturbing from the application Dev world view where people seek longer names for reasons, but after spending time in FP/LP and math you quickly forget long names. You seek variable count reduction most the time also.
This comment hits the nail on the head - if you think in terms of expressions and subsequently, expression substitution; there sometimes /is/ no good name for something.
This is /especially/ true for abstract code - functions like identity, const, map.
It seems rust compiler team didn't write a proper error message or I cannot find meaning in this .. usually _ means 'whatever type' but <_,_,_> is useless if all types are the same whatever.
It's very disturbing from the application Dev world view where people seek longer names for reasons, but after spending time in FP/LP and math you quickly forget long names. You seek variable count reduction most the time also.