From 94d27c433ed61cb9734699b1fed15a0dcee66a4e Mon Sep 17 00:00:00 2001
From: Earlopain <14981592+Earlopain@users.noreply.github.com>
Date: Tue, 20 Jan 2026 13:38:50 +0100
Subject: [PATCH] Handle `on_sp` when using prism

It used to not emit this token type, but now it does.
So when a newer version of prism is present, we can fall back
to the same code that ripper uses.

Ref:
* https://github.com/ruby/ruby/pull/15914
* https://github.com/ruby/prism/pull/3859
---
 CHANGELOG.md                    | 2 ++
 lib/syntax_suggest/code_line.rb | 7 +++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ee4c4da..60f0cbd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## HEAD (unreleased)
 
+- Fix: Correctly identify trailing slashes when using Prism > 1.8.0. (https://github.com/ruby/syntax_suggest/pull/241)
+
 ## 2.0.2
 
 - Fix: Separate multiple parser errors by newline. (https://github.com/ruby/syntax_suggest/pull/232)
diff --git a/lib/syntax_suggest/code_line.rb b/lib/syntax_suggest/code_line.rb
index 58197e9..892c273 100644
--- a/lib/syntax_suggest/code_line.rb
+++ b/lib/syntax_suggest/code_line.rb
@@ -180,10 +180,13 @@ def ignore_newline_not_beg?
     #     EOM
     #     expect(lines.first.trailing_slash?).to eq(true)
     #
-    if SyntaxSuggest.use_prism_parser?
+    if SyntaxSuggest.use_prism_parser? && Prism::VERSION <= "1.8.0"
+      # Older versions of prism didn't correctly emit on_sp
       def trailing_slash?
         last = @lex.last
-        last&.type == :on_tstring_end
+        return false unless last
+
+        last.type == :on_tstring_end || (last.type == :on_sp && last.token == TRAILING_SLASH)
       end
     else
       def trailing_slash?