learn to count newlines correctly in multiline comments

tests/test_parser.py

@@ -2751,3 +2751,15 @@ def test_multiline_comments(self, space):
 
         with self.raises(space, 'SyntaxError'):
             space.parse("=begin\nbar\n=foo")
+
+    def test_multiline_comments_lineno(self, space):
+        r = space.parse("""
+=begin
+some
+lines
+=end
+        1 + 1
+        """)
+        assert r == ast.Main(ast.Block([
+            ast.Statement(ast.Send(ast.ConstantInt(1), "+", [ast.ConstantInt(1)], None, 6))
+        ]))

topaz/lexer.py

@@ -376,6 +376,7 @@ def multiline_comment(self, ch):
             if ch == self.EOF:
                 self.error("embedded document meets end of file")
             if ch in "\r\n":
+                self.newline(ch)
                 if (self.read() == "=" and
                     self.read() == "e" and
                     self.read() == "n" and