[ruby-core:107459] [Ruby master Bug#18569] RubyVM::InstructionSequence#disasm returns nil for composed functions

Issue #18569 has been reported by GabrielMalakias (Gabriel  Malaquias).

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Bug #18569: RubyVM::InstructionSequence#disasm returns nil for composed functions
https://bugs.ruby-lang.org/issues/18569

* Author: GabrielMalakias (Gabriel  Malaquias)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.0
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
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I was testing function composition Proc#>> (https://ruby-doc.org/core-2.6/Proc.html#method-i-3E-3E) and noticed that when disassembling composed functions it always returns nil.

``` ruby
first_proc = proc { |x| x + 2 }
puts RubyVM::InstructionSequence.disasm(first_proc)

# returns 
# == disasm: #<ISeq:block in <main>@disasm.rb:3 (3,18)-(3,31)> (catch: FALSE)
# local table (size: 1, argc: 1 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1])
# [ 1] x@0<Arg>
# 0000 getlocal_WC_0                          x@0                       (   3)[LiBc]
# 0002 putobject                              2
# 0004 opt_plus                               <calldata!mid:+, argc:1, ARGS_SIMPLE>[CcCr]
# 0006 leave                                  [Br]
# -------------------------------------

puts RubyVM::InstructionSequence.disasm(first_proc >> first_proc)
# return nil
```

Is this expected or there is something weird happening here? I'm happy to help fixing it with some help in case it's a bug


---Files--------------------------------
disasm.rb (631 Bytes)


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