#10327 Now hashtags get parsed as comment starters if they are prefixed with any whitespace.

crates/nu-parser/src/lex.rs

@@ -149,8 +149,11 @@ pub fn lex_item(
                 quote_start = None;
             }
         } else if c == b'#' && !in_comment {
-            // To start a comment, It either need to be the first character of the token or prefixed with space.
-            in_comment = previous_char.map(|pc| pc == b' ').unwrap_or(true);
+            // To start a comment, It either need to be the first character of the token or prefixed with whitespace.
+            in_comment = previous_char
+                .map(char::from)
+                .map(char::is_whitespace)
+                .unwrap_or(true);
         } else if c == b'\n' || c == b'\r' {
             in_comment = false;
             if is_item_terminator(&block_level, c, additional_whitespace, special_tokens) {

crates/nu-parser/tests/test_lex.rs

@@ -182,6 +182,20 @@ fn lex_comment_with_space_in_front_of_hashtag() {
     ));
 }
 
+#[test]
+fn lex_comment_with_tab_in_front_of_hashtag() {
+    let file = b"1..10 | each {echo test\t#testing }";
+
+    let output = lex(file, 0, &[], &[], false);
+
+    assert!(output.1.is_some());
+    assert!(matches!(
+        output.1.unwrap(),
+        ParseError::UnexpectedEof(missing_token, span) if missing_token == "}"
+            && span == Span::new(33, 34)
+    ));
+}
+
 #[test]
 fn lex_is_incomplete() {
     let file = b"let x = 300 | ;";