core.typed

Confusing error message when using clojure.core/defprotocol instead of clojure.core.typed/defprotocol>

Details

  • Type: Defect Defect
  • Status: Closed Closed
  • Priority: Minor Minor
  • Resolution: Completed
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: None
  • Labels:
    None
  • Environment:
    Clojure 1.5, core.typed 0.2.2

Description

Type checking a namespace using clojure.core/defprotocol instead of clojure.core.typed/defprotocol> results in the following error:

Exception in thread "main" java.lang.AssertionError: Assert failed: 4: Cannot set! (U nil clojure.lang.MethodImplCache) to Any

Form:
        (set! (. f__5866__auto__ __methodImplCache) cache__5865__auto__)
(sub/subtype? (-> cval expr-type ret-t) (-> ctarget expr-type ret-t))

Here's a minimal project demonstrating the problem: https://github.com/noidi/core.typed-record-problem

Although the user guide mentions defprotocol>, it's very easy to run into this error by accident, and the error message does not give the user any hints as to what might be wrong. In the long term it would be best if core.typed could deal with clojure.core/defprotocol. As a stopgap measure, maybe core.typed could detect this error and instruct the user to use clojure.core.typed/defprotocol> instead?

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  • Created:
    Updated:
    Resolved: