Primitive type hints on function names should throw
Description
Functions returning primitives should be hinted with metadata on the argument list, not on the function name (which attaches to the var). Using a primitive type hint on a function name will be evaluated to the clojure.core function and should print an error message.
Currently, misplaced primitive hints are read without error but can blow up if used later.
Related variant exists for defs:
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Rich Hickey August 21, 2023 at 2:03 PM
this story needs work. The problem is one thing but this story is written in terms of a (likely wrong/breaking) solution
Alex Miller July 10, 2017 at 8:10 PM
Description could use some examples
lvh July 2, 2016 at 4:07 PM
Alternatively, perhaps the compiler could simply use the type hint? While ^long is useless now, its intent seems unambiguous.
Andy Fingerhut February 24, 2015 at 3:20 AM
One can type hint a primitive value on a Var naming a function, or any value one wants, like so:
(def {:tag 'long} foo 17)
(defn {:tag 'double} bar [x y] (* 2.0 x y))
I think it is odd that one must use {:tag 'long} instead of ^long, since trying to use ^long ends up giving the useless type hint that is the value of the function clojure.core/long.
However, the Clojure compiler will use the primitive type hints as shown in the examples above to avoid reflection in appropriate Java interop calls, so making them an error seems undesirable.
Functions returning primitives should be hinted with metadata on the argument list, not on the function name (which attaches to the var). Using a primitive type hint on a function name will be evaluated to the clojure.core function and should print an error message.
Currently, misplaced primitive hints are read without error but can blow up if used later.
Related variant exists for defs: