Fix failing to parse GO after a comment

Author: aharpervc

src/parser/mod.rs

@@ -16501,6 +16501,12 @@ impl<'a> Parser<'a> {
             match prev_token.token {
                 Token::Whitespace(ref w) => match w {
                     Whitespace::Newline => break,
+                    Whitespace::SingleLineComment { comment, prefix: _ } => {
+                        if comment.ends_with('\n') {
+                            break;
+                        }
+                        look_back_count += 1;
+                    }
                     _ => look_back_count += 1,
                 },
                 _ => {

tests/sqlparser_mssql.rs

@@ -2553,6 +2553,20 @@ fn parse_mssql_go_keyword() {
     assert_eq!(stmts[1], Statement::Go(GoStatement { count: Some(5) }));
     assert_eq!(stmts[3], Statement::Go(GoStatement { count: None }));
 
+    let single_line_comment_preceding_go = "USE some_database; -- okay\nGO";
+    let stmts = ms()
+        .parse_sql_statements(single_line_comment_preceding_go)
+        .unwrap();
+    assert_eq!(stmts.len(), 2);
+    assert_eq!(stmts[1], Statement::Go(GoStatement { count: None }));
+
+    let multi_line_comment_preceding_go = "USE some_database; /* okay */\nGO";
+    let stmts = ms()
+        .parse_sql_statements(multi_line_comment_preceding_go)
+        .unwrap();
+    assert_eq!(stmts.len(), 2);
+    assert_eq!(stmts[1], Statement::Go(GoStatement { count: None }));
+
     let comment_following_go = "USE some_database;\nGO -- okay";
     let stmts = ms().parse_sql_statements(comment_following_go).unwrap();
     assert_eq!(stmts.len(), 2);