Issue #21711 has been reported by tompng (tomoya ishida). ---------------------------------------- Bug #21711: Prism and parse.y parses private endless method definition with block differently https://bugs.ruby-lang.org/issues/21711 * Author: tompng (tomoya ishida) * Status: Open * ruby -v: ruby 4.0.0dev (2025-11-26T06:41:42Z master 43ed35de6c) +YJIT +MN +PRISM [arm64-darwin24] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- In the following code, `do end` block is passed to `private` in Prism but passed to `tap` in parse.y ~~~ruby private def f = tap do end f # different result(prism: LocalJumpError, parsey: returns main) ~~~ According to https://bugs.ruby-lang.org/issues/17398#note-10, `private def hello = puts "Hello" do expr end` should be parsed as `private (def hello = puts "Hello") do expr end`. This is correctly implemented in both Prism and parse.y, but when rhs is `tap do end`, there is a discrepancy. Another example. Prism: parse success, parse.y: syntax error. ~~~ruby private def f = 1 do end ~~~ -- https://bugs.ruby-lang.org/