[PRISM] Fix segv with regex once flag

When you have an interpolated regex with a `once` flag and local
variable is outside the block created by the `once` flag, Prism would
see a segv. This is because it was not taking the depth into account.

To fix this, we need to add 1 to the `local_depth_offset` on the
`scope`.

Fixes: ruby/prism#2047

1 files changed, 1 insertions, 0 deletions

diff --git a/test/ruby/test_compile_prism.rb b/test/ruby/test_compile_prism.rb
index e95baf5d5c..0409fc3e46 100644
--- a/test/ruby/test_compile_prism.rb
+++ b/test/ruby/test_compile_prism.rb
@@ -601,6 +601,7 @@ module Prism
       assert_prism_eval('/pit/ne')
 
       assert_prism_eval('2.times.map { /#{1}/o }')
+      assert_prism_eval('2.times.map { foo = 1; /#{foo}/o }')
     end
 
     def test_StringNode