Add test fixture for malformed regex capture name escape encoding

Author: stevenjohnstone

snapshots/regex_capture_escape_encoding_malformed.txt

@@ -0,0 +1,39 @@
+@ ProgramNode (location: (1,0)-(2,18))
+├── flags: ∅
+├── locals: []
+└── statements:
+    @ StatementsNode (location: (1,0)-(2,18))
+    ├── flags: ∅
+    └── body: (length: 2)
+        ├── @ CallNode (location: (1,0)-(1,27))
+        │   ├── flags: newline
+        │   ├── receiver:
+        │   │   @ RegularExpressionNode (location: (1,0)-(1,18))
+        │   │   ├── flags: static_literal, forced_us_ascii_encoding
+        │   │   ├── opening_loc: (1,0)-(1,1) = "/"
+        │   │   ├── content_loc: (1,1)-(1,17) = "(?<\\u{21!3}>foo)"
+        │   │   ├── closing_loc: (1,17)-(1,18) = "/"
+        │   │   └── unescaped: "(?<\\u{21!3}>foo)"
+        │   ├── call_operator_loc: ∅
+        │   ├── name: :=~
+        │   ├── message_loc: (1,19)-(1,21) = "=~"
+        │   ├── opening_loc: ∅
+        │   ├── arguments:
+        │   │   @ ArgumentsNode (location: (1,22)-(1,27))
+        │   │   ├── flags: ∅
+        │   │   └── arguments: (length: 1)
+        │   │       └── @ StringNode (location: (1,22)-(1,27))
+        │   │           ├── flags: ∅
+        │   │           ├── opening_loc: (1,22)-(1,23) = "\""
+        │   │           ├── content_loc: (1,23)-(1,26) = "foo"
+        │   │           ├── closing_loc: (1,26)-(1,27) = "\""
+        │   │           └── unescaped: "foo"
+        │   ├── closing_loc: ∅
+        │   ├── equal_loc: ∅
+        │   └── block: ∅
+        └── @ RegularExpressionNode (location: (2,0)-(2,18))
+            ├── flags: newline, static_literal, forced_us_ascii_encoding
+            ├── opening_loc: (2,0)-(2,1) = "/"
+            ├── content_loc: (2,1)-(2,17) = "(?<\\u{21!3}>foo)"
+            ├── closing_loc: (2,17)-(2,18) = "/"
+            └── unescaped: "(?<\\u{21!3}>foo)"

test/prism/fixtures/regex_capture_escape_encoding_malformed.txt

@@ -0,0 +1,2 @@
+/(?<\u{21!3}>foo)/ =~ "foo"
+/(?<\u{21!3}>foo)/

test/prism/lex_test.rb

@@ -20,6 +20,8 @@ class LexTest < TestCase
       # is a line continuation preceded by escaped backslashes. It should emit two, same
       # as if the backslashes are not present.
       "heredocs_with_fake_newlines.txt",
+      # Prism is currently silent on malformed escapes in regexes
+      "regex_capture_escape_encoding_malformed.txt"
     ]
 
     if RUBY_VERSION < "3.3.0"

test/prism/ruby/parser_test.rb

@@ -76,6 +76,9 @@ class ParserTest < TestCase
 
       # https://bugs.ruby-lang.org/issues/21168#note-5
       "command_method_call_2.txt",
+
+      # Prism is currently silent on malformed escapes in regexes
+      "regex_capture_escape_encoding_malformed.txt"
     ]
 
     # These files contain code that is being parsed incorrectly by the parser

test/prism/ruby/ripper_test.rb

@@ -51,6 +51,7 @@ class RipperTest < TestCase
       "dos_endings.txt",
       "heredocs_with_fake_newlines.txt",
       "heredocs_with_ignored_newlines.txt",
+      "regex_capture_escape_encoding_malformed.txt",
       "seattlerb/block_call_dot_op2_brace_block.txt",
       "seattlerb/block_command_operation_colon.txt",
       "seattlerb/block_command_operation_dot.txt",

test/prism/ruby/ruby_parser_test.rb

@@ -45,6 +45,7 @@ class RubyParserTest < TestCase
       "not.txt",
       "patterns.txt",
       "regex.txt",
+      "regex_capture_escape_encoding_malformed.txt",
       "seattlerb/and_multi.txt",
       "seattlerb/heredoc__backslash_dos_format.txt",
       "seattlerb/heredoc_bad_hex_escape.txt",