Wired compiler error, BUG: called type_id for Array(Config)+.class (Crystal::VirtualMetaclassType) (Exception)

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1

I want to refactor my shards to use polydocopt to rewrite the sub-command parser, but when I added this shards into my project, and requireing it, i get following strange compiler error when run shards buld

 ╰──➤ $ shards build
Dependencies are satisfied
Building: new_app
Error target new_app failed to compile:
BUG: called type_id for Array(Config)+.class (Crystal::VirtualMetaclassType) (Exception)
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  from /home/zw963/Crystal/bin/crystal in '__crystal_main'
  from /home/zw963/Crystal/bin/crystal in 'main'
  from /usr/lib/libc.so.6 in '??'
  from /usr/lib/libc.so.6 in '__libc_start_main'
  from /home/zw963/Crystal/bin/crystal in '_start'
  from ???
Error: you've found a bug in the Crystal compiler. Please open an issue, including source code that will allow us to reproduce the bug: https://github.com/crystal-lang/crystal/issues

Following is a reduced reproducible project.

  1. git clone GitHub - zw963/new_app
  2. shards install
  3. shards build

AFAIK, this issue introduced after require docopt shard, but the really issue is:

  1. I can’t understand the error message, the only things i know is, this probably a compiler bug?
  2. Why does the compiler print such a useless log? (Filled with ??, but without source code line number)
2

Does it work if you make it use GitHub - ralsina/docopt.cr: docopt for crystal-lang via shards override instead of the original? This fork contains some bug fixes that the other shard was doing that was kinda frowned upon.

Usually this means you’re using a production binary that had debug symbols stripped.

1 Like
3

Thanks, It works after switch to use ralsina/docopt.cr.

But, the issue is, why original version code can broken compiler? a normal compiler error message should not print like this, right?

4

Related: Why is this failing?. If I had to guess, it’s a different manifestation of why it’s bad to inherit from Array, or other stdlib types.

1 Like
5

I create a issue on the Github for compiler.

Regardless of how, I believe compiler printing out such a large amount of meaningless log not behavior correct.

6

As Blacksmoke16 said, this issue caused by inherit from Array, following is the diff screenshot for original old broken version(left) with forked working version(right)

image
image2311×658 115 KB

but as a user, we can’t control if one shards use it like that, compiler should tell user what happened instead of many meaningless info.

1 Like