fix(parser): empty span of unbalanced delimiter

Author: blindFS

crates/nu-command/tests/commands/let_.rs

@@ -123,3 +123,12 @@ fn let_raw_string() {
     let actual = nu!(r#"let x = r#'abc'#; $x"#);
     assert_eq!(actual.out, "abc");
 }
+
+#[test]
+fn let_malformed_type() {
+    let actual = nu!("let foo: )a");
+    assert!(actual.err.contains("unbalanced ( and )"));
+
+    let actual = nu!("let foo: }a");
+    assert!(actual.err.contains("unbalanced { and }"));
+}

crates/nu-parser/src/lex.rs

@@ -194,9 +194,9 @@ pub fn lex_item(
             } else {
                 // We encountered a closing `}` delimiter, but the last opening
                 // delimiter was not a `{`. This is an error.
+                *curr_offset += 1;
                 let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
 
-                *curr_offset += 1;
                 return (
                     Token {
                         contents: TokenContents::Item,
@@ -205,7 +205,7 @@ pub fn lex_item(
                     Some(ParseError::Unbalanced(
                         "{".to_string(),
                         "}".to_string(),
-                        Span::new(span.end, span.end + 1),
+                        Span::new(span.end - 1, span.end),
                     )),
                 );
             }
@@ -219,9 +219,9 @@ pub fn lex_item(
             } else {
                 // We encountered a closing `)` delimiter, but the last opening
                 // delimiter was not a `(`. This is an error.
+                *curr_offset += 1;
                 let span = Span::new(span_offset + token_start, span_offset + *curr_offset);
 
-                *curr_offset += 1;
                 return (
                     Token {
                         contents: TokenContents::Item,
@@ -230,7 +230,7 @@ pub fn lex_item(
                     Some(ParseError::Unbalanced(
                         "(".to_string(),
                         ")".to_string(),
-                        Span::new(span.end, span.end + 1),
+                        Span::new(span.end - 1, span.end),
                     )),
                 );
             }