fix: Show multiple line removals in Diff format

Author: Muscraft

src/renderer/render.rs

@@ -1479,7 +1479,10 @@ fn emit_suggestion_default(
         row_num += 1;
     }
 
-    let file_lines = sm.span_to_lines(parts[0].span.clone());
+    let lo = parts.iter().map(|p| p.span.start).min().unwrap();
+    let hi = parts.iter().map(|p| p.span.end).max().unwrap();
+
+    let file_lines = sm.span_to_lines(lo..hi);
     let (line_start, line_end) = if suggestion.fold {
         // We use the original span to get original line_start
         sm.span_to_locations(parts[0].original_span.clone())
@@ -1613,6 +1616,7 @@ fn emit_suggestion_default(
     if let DisplaySuggestion::Diff | DisplaySuggestion::Underline | DisplaySuggestion::Add =
         show_code_change
     {
+        let mut prev_lines: Option<(usize, usize)> = None;
         for part in parts {
             let snippet = sm.span_to_snippet(part.span.clone()).unwrap_or_default();
             let (span_start, span_end) = sm.span_to_locations(part.span.clone());
@@ -1702,6 +1706,12 @@ fn emit_suggestion_default(
 
                 let newlines = snippet.lines().count();
                 if newlines > 0 && row_num > newlines {
+                    let offset = match prev_lines {
+                        Some((start, end)) => {
+                            file_lines.len().saturating_sub(end.saturating_sub(start))
+                        }
+                        None => file_lines.len(),
+                    };
                     // Account for removals where the part being removed spans multiple
                     // lines.
                     // FIXME: We check the number of rows because in some cases, like in
@@ -1715,7 +1725,7 @@ fn emit_suggestion_default(
                         // Going lower than buffer_offset (+ 1) would mean
                         // overwriting existing content in the buffer
                         let min_row = buffer_offset + usize::from(!matches_previous_suggestion);
-                        let row = (row_num - 2 - (newlines - i - 1)).max(min_row);
+                        let row = (row_num - 2 - (offset - i - 1)).max(min_row);
                         // On the first line, we highlight between the start of the part
                         // span, and the end of that line.
                         // On the last line, we highlight between the start of the line, and
@@ -1746,6 +1756,7 @@ fn emit_suggestion_default(
                         true,
                     );
                 }
+                prev_lines = Some((span_start.line, span_end.line));
             }
 
             // length of the code after substitution

tests/color/multiple_multiline_removal.ascii.term.svg

@@ -2371,6 +2371,9 @@ help: consider removing the `?Sized` bound to make the type parameter `Sized`
  9 - fuzzy
 10 - pizza
 11 - jumps
+12 - crazy
+13 - quack
+14 - zappy
  8 + campy
    |
 "#]];
@@ -2386,6 +2389,9 @@ help: consider removing the `?Sized` bound to make the type parameter `Sized`
  9 - fuzzy
 10 - pizza
 11 - jumps
+12 - crazy
+13 - quack
+14 - zappy
  8 + campy
    ╰╴
 "#]];

tests/color/multiple_multiline_removal.unicode.term.svg

@@ -5325,6 +5325,9 @@ help: you might have meant to use an associated function to build this type
 help: consider using the `Default` trait
    |
 11 -         wtf: Some(Box(U {
+12 -             wtf: None,
+13 -             x: (),
+14 -         })),
 11 +         wtf: Some(<Box as std::default::Default>::default()),
    |
 "#]];
@@ -5374,6 +5377,9 @@ help: you might have meant to use an associated function to build this type
 help: consider using the `Default` trait
    ╭╴
 11 -         wtf: Some(Box(U {
+12 -             wtf: None,
+13 -             x: (),
+14 -         })),
 11 +         wtf: Some(<Box as std::default::Default>::default()),
    ╰╴
 "#]];
@@ -5775,6 +5781,10 @@ note: associated function defined here
 help: remove the extra arguments
   |
 4 -     generate_setter,
+5 -     r#"
+6 - pub(crate) struct Person<T: Clone> {}
+7 - "#,
+8 -      r#""#,
 4 +     /* usize */,
   |
 "##]];
@@ -5807,6 +5817,10 @@ note: associated function defined here
 help: remove the extra arguments
   ╭╴
 4 -     generate_setter,
+5 -     r#"
+6 - pub(crate) struct Person<T: Clone> {}
+7 - "#,
+8 -      r#""#,
 4 +     /* usize */,
   ╰╴
 "##]];
@@ -5867,7 +5881,6 @@ help: otherwise remove the non-wildcard arms
    |
 20 -         2 => 'b',
 21 -         3 => 'b',
-20 +         _ => 'b',
    |
 "#]];
     let renderer_ascii = Renderer::plain();
@@ -5889,7 +5902,6 @@ help: otherwise remove the non-wildcard arms
    ╭╴
 20 -         2 => 'b',
 21 -         3 => 'b',
-20 +         _ => 'b',
    ╰╴
 "#]];
     let renderer_unicode = renderer_ascii.decor_style(DecorStyle::Unicode);