Region with line numbers of different string length need to pad shorter line numbers

compiler/reporting/src/report.rs

@@ -165,13 +165,25 @@ impl ReportText {
             }
             Type(content) => buf.push_str(content_to_string(content, subs, home, interns).as_str()),
             Region(region) => {
+                let max_line_number_length = region.end_line.to_string().len();
+
                 for i in region.start_line..=region.end_line {
-                    buf.push_str(i.to_string().as_str());
+                    let i_one_indexed = i + 1;
+
+                    let line_number_string = i_one_indexed.to_string();
+                    let line_number = line_number_string.as_str();
+                    let this_line_number_length = line_number.len();
+
+                    buf.push_str(
+                        " ".repeat(max_line_number_length - this_line_number_length)
+                            .as_str(),
+                    );
+                    buf.push_str(line_number);
                     buf.push_str(" ┆");
 
                     let line = src_lines[i as usize];
 
-                    if !line.is_empty() {
+                    if !line.trim().is_empty() {
                         buf.push_str("  ");
                         buf.push_str(src_lines[i as usize]);
                     }

compiler/reporting/tests/test_reporting.rs

@@ -244,7 +244,7 @@ mod test_report {
                 r#"
                 y is not used anywhere in your code.
 
-                1 ┆  y = 2
+                2 ┆  y = 2
 
                 If you didn't intend on using y then remove it so future readers of your code don't wonder why it is there."#
             )
@@ -276,9 +276,44 @@ mod test_report {
             })),
             indoc!(
                 r#"
-                    1 ┆  y = 2
+                    2 ┆  y = 2
-                    2 ┆  f = \a -> a + 4
+                    3 ┆  f = \a -> a + 4
-                    3 ┆"#
+                    4 ┆"#
+            ),
+        );
+    }
+
+    #[test]
+    fn report_region_different_line_number_lengths() {
+        report_renders_as_from_src(
+            indoc!(
+                r#"
+                    x = 1
+
+
+
+
+
+
+
+
+                    y = 2
+                    f = \a -> a + 4
+
+                    f x
+                "#
+            ),
+            to_simple_report(Region(roc_region::all::Region {
+                start_line: 8,
+                end_line: 10,
+                start_col: 0,
+                end_col: 0,
+            })),
+            indoc!(
+                r#"
+                     9 ┆
+                    10 ┆  y = 2
+                    11 ┆  f = \a -> a + 4"#
             ),
         );
     }