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+1 vote
in Compiler by

Hey all :)

Have hit what I think is a compiler bug this morning, wondering whether it's one I should submit to JIRA?

Here's what I believe to be a minimal repro:

(defprotocol P
  (^double p1 [p a])
  (^double p2 [p a]))

(let [p (reify P)]
  (min 0.0
       (case :p1
         :p1 (p1 p :foo)
         :p2 (p2 p :foo))))


1. Caused by java.lang.ArrayIndexOutOfBoundsException
   Index -1 out of bounds for length 0

                Frame.java: 1262  clojure.asm.Frame/merge
                Frame.java: 1238  clojure.asm.Frame/merge
         MethodWriter.java: 1604  clojure.asm.MethodWriter/computeAllFrames
         MethodWriter.java: 1540  clojure.asm.MethodWriter/visitMaxs

... (have a fuller trace I can send, or the above code snippet should work at a REPL)

Any of the following make this error go away

  • removing the type hinting
  • adding a nil default to the case
  • making the protocol functions normal type-hinted defns
  • raising the case out of the min (removing the min)

I've managed to refactor the original code to work around the issue, but please do let me know if I should raise a JIRA ticket.



1 Answer

+1 vote

Ticket created at https://clojure.atlassian.net/browse/CLJ-2698

Please feel free to comment there as needed.
Thank you!