(long AnyInteger) doesn't typecheck

Description

reiska.core=> (t/cf (long (+ 2 (int 123))))
Type Error (/private/var/folders/x2/47j5hlbs01b9b4mjz_8fyf05m8hy4p/T/form-init7340610759194794514.clj:1:7) Static method clojure.lang.RT/longCast could not be applied to arguments:


Domains:
        long

Arguments:
        t/AnyInteger

Ranges:
        long

in: (clojure.lang.RT/longCast (clojure.lang.Numbers/add 2 (clojure.lang.RT/intCast 123)))
in: (clojure.lang.RT/longCast (clojure.lang.Numbers/add 2 (clojure.lang.RT/intCast 123)))


ExceptionInfo Type Checker: Found 1 error  clojure.core/ex-info (core.clj:4403)

Pull request: 36
Patch: ctyp-210.patch
Commit: 68d20b
Release: 0.3.9

Environment

[org.clojure/core.typed "0.2.84"]
[org.clojure/clojure "1.6.0"]

Attachments

ctyp-210.patch

22 Jul, 2015

Activity

Timo Mihaljov

April 15, 2015 at 4:57 AM

Here's what I think is going on:

1. clojure.core/long is defined as an inlineable function, so its body gets inlined and core.typed never sees the function application (long x) (where long's type is [t/Any -> Long]). Instead, it sees the method application (clojure.lang.RT/longCast x) and has to infer the method's type from its Java type.

This hypothesis is supported by the following experiment. Commenting out the inline form in a copy of clojure.core/long makes it apply cleanly to t/AnyInteger values.

;;; Doesn't typecheck

(t/ann ^:no-check my-long [t/Any -> long])
(defn my-long
  {:inline (fn [x] `(. clojure.lang.RT (longCast ~x)))}
  [^Number x]
  (clojure.lang.RT/longCast x))

(def a (my-long (t/ann-form 123 t/AnyInteger)))

;;; Typechecks

(t/ann ^:no-check my-long2 [t/Any -> long])
(defn my-long2
  ; Commented out: {:inline (fn [x] `(. clojure.lang.RT (longCast ~x)))}
  [^Number x]
  (clojure.lang.RT/longCast x))

(def b (my-long2 (t/ann-form 123 t/AnyInteger)))

2. The clojure.lang.RT/longCast method is overloaded. It seems that instead of inferring a multi-arity type, core.typed seems to pick just one of the arities. In this case it picks the wrong arity: t/AnyInteger is a valid argument to longCast(Object x), but not the picked longCast(long x).

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Completed

Details

Assignee

Ambrose Bonnaire-Sergeant

Reporter

Timo Mihaljov

Fix versions

0.3.9

0.3.x

Priority

Minor

Created April 9, 2015 at 5:27 AM

Updated December 3, 2017 at 11:07 PM

Resolved December 3, 2017 at 11:07 PM