Bug #13701: Ripper fails to parse "proc { |(w, *x, y), z| }"

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin13]
• Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN

[mjago (Martyn Jago)]

The Ruby formatter rufo has exposed a ripper parsing error when parsing the following ruby code:

proc { |(w, *x, y), z| }

The s-expression below shows that the y identifier is swallowed.

The following ruby spec fails for the same reason:

https://github.com/ruby/spec/blob/master/language/block_spec.rb#L852#L865

$ ruby -rripper -rpp -e 'pp Ripper.sexp("proc { |(w, *x, y), z| }")'

[:program,
 [[:method_add_block,
   [:method_add_arg, [:fcall, [:@ident, "proc", [1, 0]]], []],
   [:brace_block,
    [:block_var,
     [:params,
      [[:mlhs_paren,
        [:mlhs_add_star,
         [[:mlhs_paren, [:@ident, "w", [1, 9]]]],
         [:@ident, "x", [1, 13]]]],
       [:@ident, "z", [1, 20]]],
      nil,
      nil,
      nil,
      nil,
      nil,
      nil],
     false],
    [[:void_stmt]]]]]]

ref: rufo issue: https://github.com/asterite/rufo/issues/73

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r59246.

---

parse.y: f_margs parser events

• parse.y (f_margs): implemented parser events for massign
  formal arguments. [ruby-core:81848] [Bug #13701]

[mjago (Martyn Jago)]

Thank you nobu for the quick fix