[Feature #20257] Rearchitect Ripper

Introduce another semantic value stack for Ripper so that
Ripper can manage both Node and Ruby Object separately.
This rearchitectutre of Ripper solves these issues.
Therefore adding test cases for them.

* [Bug 10436] https://bugs.ruby-lang.org/issues/10436
* [Bug 18988] https://bugs.ruby-lang.org/issues/18988
* [Bug 20055] https://bugs.ruby-lang.org/issues/20055

Checked the differences of `Ripper.sexp` for files under `/test/ruby`
are only on test_pattern_matching.rb.
The differences comes from the differences between
`new_hash_pattern_tail` functions between parser and Ripper.
Ripper `new_hash_pattern_tail` didn’t call `assignable` then
`kw_rest_arg` wasn’t marked as local variable.
This is also fixed by this commit.

```
--- a/./tmp/before/test_pattern_matching.rb
+++ b/./tmp/after/test_pattern_matching.rb
@@ -3607,7 +3607,7 @@
                  [:in,
                   [:hshptn, nil, [], [:var_field, [:@ident, “a”, [984, 13]]]],
                   [[:binary,
-                    [:vcall, [:@ident, “a”, [985, 10]]],
+                    [:var_ref, [:@ident, “a”, [985, 10]]],
                     :==,
                     [:hash, nil]]],
                   nil]]],
@@ -3662,7 +3662,7 @@
                  [:in,
                   [:hshptn, nil, [], [:var_field, [:@ident, “a”, [993, 13]]]],
                   [[:binary,
-                    [:vcall, [:@ident, “a”, [994, 10]]],
+                    [:var_ref, [:@ident, “a”, [994, 10]]],
                     :==,
                     [:hash,
                      [:assoclist_from_args,
@@ -3813,7 +3813,7 @@
                    [:command,
                     [:@ident, “raise”, [1022, 10]],
                     [:args_add_block,
-                     [[:vcall, [:@ident, “b”, [1022, 16]]]],
+                     [[:var_ref, [:@ident, “b”, [1022, 16]]]],
                      false]]],
                   [:else, [[:var_ref, [:@kw, “true”, [1024, 10]]]]]]]],
                nil,
@@ -3876,7 +3876,7 @@
                      [:@int, “0”, [1033, 15]]],
                     :“&&“,
                     [:binary,
-                     [:vcall, [:@ident, “b”, [1033, 20]]],
+                     [:var_ref, [:@ident, “b”, [1033, 20]]],
                      :==,
                      [:hash, nil]]]],
                   nil]]],
@@ -3946,7 +3946,7 @@
                      [:@int, “0”, [1042, 15]]],
                     :“&&“,
                     [:binary,
-                     [:vcall, [:@ident, “b”, [1042, 20]]],
+                     [:var_ref, [:@ident, “b”, [1042, 20]]],
                      :==,
                      [:hash,
                       [:assoclist_from_args,
@@ -5206,7 +5206,7 @@
                      [[:assoc_new,
                        [:@label, “c:“, [1352, 22]],
                        [:@int, “0”, [1352, 25]]]]]],
-                   [:vcall, [:@ident, “r”, [1352, 29]]]],
+                   [:var_ref, [:@ident, “r”, [1352, 29]]]],
                   false]]],
                [:binary,
                 [:call,
@@ -5299,7 +5299,7 @@
                       [:assoc_new,
                        [:@label, “c:“, [1367, 34]],
                        [:@int, “0”, [1367, 37]]]]]],
-                   [:vcall, [:@ident, “r”, [1367, 41]]]],
+                   [:var_ref, [:@ident, “r”, [1367, 41]]]],
                   false]]],
                [:binary,
                 [:call,
@@ -5931,7 +5931,7 @@
              [:in,
               [:hshptn, nil, [], [:var_field, [:@ident, “r”, [1533, 11]]]],
               [[:binary,
-                [:vcall, [:@ident, “r”, [1534, 8]]],
+                [:var_ref, [:@ident, “r”, [1534, 8]]],
                 :==,
                 [:hash,
                  [:assoclist_from_args,
```

1 files changed, 13 insertions, 0 deletions

diff --git a/test/ripper/test_sexp.rb b/test/ripper/test_sexp.rb
index a1cf5e4f0a..32285be9ab 100644
--- a/test/ripper/test_sexp.rb
+++ b/test/ripper/test_sexp.rb
@@ -18,6 +18,11 @@ class TestRipper::Sexp < Test::Unit::TestCase
     assert_nil Ripper.sexp("/*")
     assert_nil Ripper.sexp("/*/")
     assert_nil Ripper.sexp("/+/")
+    assert_nil Ripper.sexp("m(&nil) {}"), '[Bug #10436]'
+    assert_nil Ripper.sexp("/(?<a>)/ =~ ''; x = a **a, **a if false"), '[Bug #18988]'
+    assert_nil Ripper.sexp("return + return"), '[Bug #20055]'
+    assert_nil Ripper.sexp("1 in [a, a]"), '[Bug #20055]'
+    assert_nil Ripper.sexp("1 + (1 => [a, a])"), '[Bug #20055]'
   end
 
   def test_regexp_content
@@ -34,6 +39,14 @@ class TestRipper::Sexp < Test::Unit::TestCase
     assert_equal '(?<n>a(b|\g<n>))', search_sexp(:@tstring_content, search_sexp(:regexp_literal, sexp))[1]
   end
 
+  def test_regexp_named_capture
+    sexp = Ripper.sexp("/(?<a>)/ =~ ''; x = a **a, a if false")
+    assert_not_nil sexp, '[Bug #18988]'
+
+    sexp = Ripper.sexp("/(?<a>)/ =~ ''; a %(exit)")
+    assert_equal 'exit', search_sexp(:@ident, search_sexp(:paren, sexp))[1], '[Bug #18988]'
+  end
+
   def test_heredoc_content
     sexp = Ripper.sexp("<<E\nfoo\nE")
     assert_equal "foo\n", search_sexp(:@tstring_content, sexp)[1]