Issue #19966 has been reported by nobu (Nobuyoshi Nakada).
----------------------------------------
Bug #19966: Prism defines global method instead of singleton method
https://bugs.ruby-lang.org/issues/19966
* Author: nobu (Nobuyoshi Nakada)
* Status: Open
* Priority: Normal
* Backport: 3.0: DONTNEED, 3.1: DONTNEED, 3.2: DONTNEED
----------------------------------------
The receiver is ignored and compiled to `definemethod` instead of `definesmethod`.
```
$ ./ruby -v -e 'puts RubyVM::InstructionSequence.compile_prism("def
a.foo;end").disasm'
ruby 3.3.0dev (2023-10-20T00:12:09Z master 985370406d) [arm64-darwin22]
== disasm: #<ISeq:<compiled>@<compiled>:0 (0,0)-(0,13)>
0000 definemethod :foo, foo
0003 putobject :foo
0005 leave
== disasm: #<ISeq:foo@<compiled>:0 (0,0)-(0,13)>
0000 putnil
0001 leave
```
```
$ ./ruby -v -e 'puts RubyVM::InstructionSequence.compile("def
a.foo;end").disasm'
ruby 3.3.0dev (2023-10-20T00:12:09Z master 985370406d) [arm64-darwin22]
== disasm: #<ISeq:<compiled>@<compiled>:1 (1,0)-(1,13)>
0000 putself ( 1)[Li]
0001 opt_send_without_block <calldata!mid:a, argc:0,
FCALL|VCALL|ARGS_SIMPLE>
0003 definesmethod :foo, foo
0006 putobject :foo
0008 leave
== disasm: #<ISeq:foo@<compiled>:1 (1,0)-(1,13)>
0000 putnil ( 1)[Ca]
0001 leave [Re]
```
--
https://bugs.ruby-lang.org/