diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs index e9e7065ec03..269d34ea432 100644 --- a/compiler/rustc_errors/src/emitter.rs +++ b/compiler/rustc_errors/src/emitter.rs @@ -656,11 +656,6 @@ impl Emitter for SilentEmitter { } } -/// Maximum number of lines we will print for a multiline suggestion; arbitrary. -/// -/// This should be replaced with a more involved mechanism to output multiline suggestions that -/// more closely mimics the regular diagnostic output, where irrelevant code lines are elided. -pub const MAX_SUGGESTION_HIGHLIGHT_LINES: usize = 6; /// Maximum number of suggestions to be shown /// /// Arbitrary, but taken from trait import suggestion limit @@ -1839,79 +1834,115 @@ impl EmitterWriter { } row_num += line_end - line_start; } - for (line_pos, (line, highlight_parts)) in - lines.by_ref().zip(highlights).take(MAX_SUGGESTION_HIGHLIGHT_LINES).enumerate() - { - // Print the span column to avoid confusion - buffer.puts( - row_num, - 0, - &self.maybe_anonymized(line_start + line_pos), - Style::LineNumber, - ); - if let DisplaySuggestion::Diff = show_code_change { - // Add the line number for both addition and removal to drive the point home. - // - // N - fn foo(bar: A) { - // N + fn foo(bar: impl T) { + let mut unhighlighted_lines = Vec::new(); + for (line_pos, (line, highlight_parts)) in lines.by_ref().zip(highlights).enumerate() { + debug!(%line_pos, %line, ?highlight_parts); + + let print_line = |line_pos: usize, + line: &str, + highlight_parts: &Vec, + buffer: &mut StyledBuffer, + row_num: &mut usize| { + // Print the span column to avoid confusion buffer.puts( - row_num - 1, + *row_num, 0, &self.maybe_anonymized(line_start + line_pos), Style::LineNumber, ); - buffer.puts(row_num - 1, max_line_num_len + 1, "- ", Style::Removal); - buffer.puts( - row_num - 1, - max_line_num_len + 3, - &normalize_whitespace( - &*file_lines - .file - .get_line(file_lines.lines[line_pos].line_index) - .unwrap(), - ), - Style::NoStyle, - ); - buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition); - } else if is_multiline { - match &highlight_parts[..] { - [SubstitutionHighlight { start: 0, end }] if *end == line.len() => { - buffer.puts(row_num, max_line_num_len + 1, "+ ", Style::Addition); - } - [] => { - draw_col_separator(&mut buffer, row_num, max_line_num_len + 1); - } - _ => { - buffer.puts(row_num, max_line_num_len + 1, "~ ", Style::Addition); + if let DisplaySuggestion::Diff = show_code_change { + // Add the line number for both addition and removal to drive the point home. + // + // N - fn foo(bar: A) { + // N + fn foo(bar: impl T) { + buffer.puts( + *row_num - 1, + 0, + &self.maybe_anonymized(line_start + line_pos), + Style::LineNumber, + ); + buffer.puts(*row_num - 1, max_line_num_len + 1, "- ", Style::Removal); + buffer.puts( + *row_num - 1, + max_line_num_len + 3, + &normalize_whitespace( + &*file_lines + .file + .get_line(file_lines.lines[line_pos].line_index) + .unwrap(), + ), + Style::NoStyle, + ); + buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition); + } else if is_multiline { + match &highlight_parts[..] { + [SubstitutionHighlight { start: 0, end }] if *end == line.len() => { + buffer.puts(*row_num, max_line_num_len + 1, "+ ", Style::Addition); + } + [] => { + draw_col_separator(buffer, *row_num, max_line_num_len + 1); + } + _ => { + buffer.puts(*row_num, max_line_num_len + 1, "~ ", Style::Addition); + } } + } else { + draw_col_separator(buffer, *row_num, max_line_num_len + 1); } - } else { - draw_col_separator(&mut buffer, row_num, max_line_num_len + 1); + + // print the suggestion + buffer.append(*row_num, &normalize_whitespace(line), Style::NoStyle); + + // Colorize addition/replacements with green. + for &SubstitutionHighlight { start, end } in highlight_parts { + // Account for tabs when highlighting (#87972). + let tabs: usize = line + .chars() + .take(start) + .map(|ch| match ch { + '\t' => 3, + _ => 0, + }) + .sum(); + buffer.set_style_range( + *row_num, + max_line_num_len + 3 + start + tabs, + max_line_num_len + 3 + end + tabs, + Style::Addition, + true, + ); + } + *row_num += 1; + }; + + if highlight_parts.is_empty() { + unhighlighted_lines.push((line_pos, line)); + continue; } - // print the suggestion - buffer.append(row_num, &normalize_whitespace(line), Style::NoStyle); - - // Colorize addition/replacements with green. - for &SubstitutionHighlight { start, end } in highlight_parts { - // Account for tabs when highlighting (#87972). - let tabs: usize = line - .chars() - .take(start) - .map(|ch| match ch { - '\t' => 3, - _ => 0, - }) - .sum(); - buffer.set_style_range( - row_num, - max_line_num_len + 3 + start + tabs, - max_line_num_len + 3 + end + tabs, - Style::Addition, - true, - ); + match unhighlighted_lines.len() { + 0 => (), + // Since we show first line, "..." line and last line, + // There is no reason to hide if there are 3 or less lines + // (because then we just replace a line with ... which is + // not helpful) + n if n <= 3 => unhighlighted_lines.drain(..).for_each(|(p, l)| { + print_line(p, l, &Vec::new(), &mut buffer, &mut row_num) + }), + _ => { + unhighlighted_lines + .drain(..1) + .next() + .map(|(p, l)| print_line(p, l, &Vec::new(), &mut buffer, &mut row_num)); + buffer.puts(row_num, max_line_num_len - 1, "...", Style::LineNumber); + row_num += 1; + unhighlighted_lines + .pop() + .map(|(p, l)| print_line(p, l, &Vec::new(), &mut buffer, &mut row_num)); + } } - row_num += 1; + + print_line(line_pos, line, highlight_parts, &mut buffer, &mut row_num) } // This offset and the ones below need to be signed to account for replacement code