Nil assertion failed in codegen_fun when using closured object inside captured block inside CONST initializer

[RX14]

I was writing my first Crystal code for a while and I managed to hit this in 5 minutes! I think I have previous maintainer's bad luck.

Here's a minimal test case, which reproduces with --prelude=empty:

class Foo
  def bar
  end
end

def func(&block)
  block.call
end

CONST = begin
  foo = Foo.new
  func do
    foo.bar
  end
end

CONST

Backtrace:

Nil assertion failed (NilAssertionError)
  from /data/programming/crystal-lang/crystal/master/src/nil.cr:106:5 in 'not_nil!'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/fun.cr:103:47 in 'codegen_fun'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/fun.cr:51:3 in 'codegen_fun:fun_module_info:is_fun_literal:is_closure'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/codegen.cr:549:17 in 'visit'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/syntax/visitor.cr:27:12 in 'accept'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/codegen.cr:2184:7 in 'accept'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/call.cr:318:5 in 'codegen_call_with_block_as_fun_literal'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/call.cr:30:9 in 'visit'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/syntax/visitor.cr:27:12 in 'accept'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/codegen.cr:2184:7 in 'accept'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/codegen.cr:619:9 in 'visit'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/syntax/visitor.cr:27:12 in 'accept'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/codegen.cr:2184:7 in 'accept'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/const.cr:159:13 in 'create_initialize_const_function'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/const.cr:131:56 in 'initialize_const'
  from /data/programming/crystal-lang/crystal/master/src/compiler/crystal/codegen/codegen.cr:930:9 in 'codegen_assign'
... boring codegen visitor doing it's visiting, clipped for length

[asterite]

Hi!

I'd love to help but I can't compile the compiler anymore :-(

Undefined symbols for architecture x86_64:
  "_roundeven", referenced from:
      _*Float64#round_even:Float64 in F-loat64.o

This is on Mac OSX, LLVM 11.1.0

@straight-shoota Any ideas?

[asterite]

By the way, the issue seems to be that closures don't work right now inside const initializations. It should be easy to fix... once I can get things compiling again. Maybe I'll stick with LLVM 10 for now.

[asterite]

Same error... :-(

[straight-shoota]

@asterite This is weird, and definitely a different issue. You can just revert the last commit (or just checkout master^).

[RX14]

I'm looking into a patch for this, it's interesting poking around in the compiler anyway :)