core.typed use case

desired_code.clj

(require '[clojure.core.typed :as t])

;; Instead of via namespaces
(t/check-ns 'valid-ns)
(t/check-ns 'invalid-ns)

;; I would like to have something like this to work
(t/cf      
  (let [a (fn [x] x)
        _ (t/ann ^:no-check a [Number -> Number])
        b (fn [x] (a 1))
        _ (t/ann-form b  [Number -> Number])]
    (b 1)))

invalid_ns.clj

(ns invalid-ns
  (:require [clojure.core.typed :as t]))

;; Missing checks here
(defn unchecked-f [x]
  (str "no-int"))

(let [a unchecked-f
      b (fn [x] (a 1))
      _ (t/ann-form b  [Number -> Number])]
  (b 1))

proper.clj

(t/cf      
  (let [a (t/cast [Number :-> Number] (fn [x] x))
         b (fn [x] (a 1))
         _ (t/ann-form b  [Number -> Number])]
    (b 1)))
  ;=> Number
  
  (let [x (try
  (t/cf      
  (let [a (t/cast [Number :-> Number] (fn [x] x))
         b (fn [x] (a 1))
         _ (t/ann-form b  [Number -> Number])]
    (b 1)))
  (catch Exception e e))
   ]
  (if-let [error (ex-data x)]
      error
      :ok))
  ;=> :ok
  
  (let [x (try
  (t/cf      
  (let [a (t/cast [String :-> Number] (fn [x] x))
         b (fn [x] (a 1))
         _ (t/ann-form b  [Number -> Number])]
    (b 1)))
  ;; Fixme Exception is still being printed here
  (catch Exception e e))
   ]
  (if-let [msg (some-> x ex-data :errors first .getMessage)]
      msg
      :ok))
    ;=> "Function a could not be applied to arguments:\n\n\nDomains:\n\tString\n\nArguments:\n\t(t/Val 1)\n\nRanges:\n\tNumber\n\n"

valid_ns.clj

(ns valid-ns
  (:require [clojure.core.typed :as t]))

(t/ann ^:no-check unchecked-f [Number -> Number])
(defn unchecked-f [x]
  (str "no-int"))

(let [a unchecked-f
      b (fn [x] (a 1))
      _ (t/ann-form b  [Number -> Number])]
  (b 1))