[Bug #20030] dispatch invalid escaped character without ignoring it

3 files changed, 26 insertions, 2 deletions

diff --git a/parse.y b/parse.y
index 865d26c0f3..1e59e832ec 100644
--- a/parse.y
+++ b/parse.y
@@ -7878,6 +7878,16 @@ tokadd_codepoint(struct parser_params *p, rb_encoding **encp,
 
 static int tokadd_mbchar(struct parser_params *p, int c);
 
+static int
+tokskip_mbchar(struct parser_params *p)
+{
+    int len = parser_precise_mbclen(p, p->lex.pcur-1);
+    if (len > 0) {
+        p->lex.pcur += len - 1;
+    }
+    return len;
+}
+
 /* return value is for ?\u3042 */
 static void
 tokadd_utf8(struct parser_params *p, rb_encoding **encp,
@@ -8065,7 +8075,11 @@ read_escape(struct parser_params *p, int flags)
         }
         else if (c == '?')
             return 0177;
-        else if (c == -1 || !ISASCII(c)) goto eof;
+        else if (c == -1) goto eof;
+        else if (!ISASCII(c)) {
+            tokskip_mbchar(p);
+            goto eof;
+        }
         else {
             int c2 = escaped_control_code(c);
             if (c2) {
@@ -8093,7 +8107,7 @@ read_escape(struct parser_params *p, int flags)
       eof:
       case -1:
         yyerror0("Invalid escape character syntax");
-        token_flush(p);
+        dispatch_scan_event(p, tSTRING_CONTENT);
         return '\0';
 
       default:
diff --git a/test/ripper/test_scanner_events.rb b/test/ripper/test_scanner_events.rb
index 8434cc9c40..9739cdb1eb 100644
--- a/test/ripper/test_scanner_events.rb
+++ b/test/ripper/test_scanner_events.rb
@@ -991,6 +991,12 @@ class TestRipper::ScannerEvents < Test::Unit::TestCase
     assert_equal("\e", err[2])
   end
 
+  def test_invalid_escape
+    err = nil
+    assert_equal ["\\C-\u{3042}"], scan('tstring_content', %["\\C-\u{3042}"]) {|*e| err = e}
+    assert_equal [:on_parse_error, "Invalid escape character syntax", "\\C-\u{3042}"], err
+  end
+
   def test_invalid_hex_escape
     err = nil
     assert_equal ['U'], scan('tstring_content', '"\\xU"') {|*e| err = e}
diff --git a/test/ruby/test_parse.rb b/test/ruby/test_parse.rb
index 2960a3c295..6121205857 100644
--- a/test/ruby/test_parse.rb
+++ b/test/ruby/test_parse.rb
@@ -603,6 +603,10 @@ class TestParse < Test::Unit::TestCase
     assert_equal(' ^~~~~'"\n", e.message.lines.last)
     e = assert_syntax_error('"\M-\U0000"', 'Invalid escape character syntax')
     assert_equal(' ^~~~~'"\n", e.message.lines.last)
+
+    e = assert_syntax_error(%["\\C-\u3042"], 'Invalid escape character syntax')
+    assert_match(/^\s \^(?# \\ ) ~(?# C ) ~(?# - ) ~+(?# U+3042 )$/x, e.message.lines.last)
+    assert_not_include(e.message, "invalid multibyte char")
   end
 
   def test_question