diff options
Diffstat (limited to 'compiler/rustc_errors/src/emitter.rs')
| -rw-r--r-- | compiler/rustc_errors/src/emitter.rs | 86 |
1 files changed, 79 insertions, 7 deletions
diff --git a/compiler/rustc_errors/src/emitter.rs b/compiler/rustc_errors/src/emitter.rs index 977721a5b8a..f938352820d 100644 --- a/compiler/rustc_errors/src/emitter.rs +++ b/compiler/rustc_errors/src/emitter.rs @@ -2216,6 +2216,11 @@ impl HumanEmitter { show_code_change { for part in parts { + let snippet = if let Ok(snippet) = sm.span_to_snippet(part.span) { + snippet + } else { + String::new() + }; let span_start_pos = sm.lookup_char_pos(part.span.lo()).col_display; let span_end_pos = sm.lookup_char_pos(part.span.hi()).col_display; @@ -2263,13 +2268,80 @@ impl HumanEmitter { } if let DisplaySuggestion::Diff = show_code_change { // Colorize removal with red in diff format. - buffer.set_style_range( - row_num - 2, - (padding as isize + span_start_pos as isize) as usize, - (padding as isize + span_end_pos as isize) as usize, - Style::Removal, - true, - ); + + // Below, there's some tricky buffer indexing going on. `row_num` at this + // point corresponds to: + // + // | + // LL | CODE + // | ++++ <- `row_num` + // + // in the buffer. When we have a diff format output, we end up with + // + // | + // LL - OLDER <- row_num - 2 + // LL + NEWER + // | <- row_num + // + // The `row_num - 2` is to select the buffer line that has the "old version + // of the diff" at that point. When the removal is a single line, `i` is + // `0`, `newlines` is `1` so `(newlines - i - 1)` ends up being `0`, so row + // points at `LL - OLDER`. When the removal corresponds to multiple lines, + // we end up with `newlines > 1` and `i` being `0..newlines - 1`. + // + // | + // LL - OLDER <- row_num - 2 - (newlines - last_i - 1) + // LL - CODE + // LL - BEING + // LL - REMOVED <- row_num - 2 - (newlines - first_i - 1) + // LL + NEWER + // | <- row_num + + let newlines = snippet.lines().count(); + if newlines > 0 && row_num > newlines { + // Account for removals where the part being removed spans multiple + // lines. + // FIXME: We check the number of rows because in some cases, like in + // `tests/ui/lint/invalid-nan-comparison-suggestion.rs`, the rendered + // suggestion will only show the first line of code being replaced. The + // proper way of doing this would be to change the suggestion rendering + // logic to show the whole prior snippet, but the current output is not + // too bad to begin with, so we side-step that issue here. + for (i, line) in snippet.lines().enumerate() { + let line = normalize_whitespace(line); + let row = row_num - 2 - (newlines - i - 1); + // 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 + // the column of the part span end. + // On all others, we highlight the whole line. + let start = if i == 0 { + (padding as isize + span_start_pos as isize) as usize + } else { + padding + }; + let end = if i == 0 { + (padding as isize + + span_start_pos as isize + + line.len() as isize) + as usize + } else if i == newlines - 1 { + (padding as isize + span_end_pos as isize) as usize + } else { + (padding as isize + line.len() as isize) as usize + }; + buffer.set_style_range(row, start, end, Style::Removal, true); + } + } else { + // The removed code fits all in one line. + buffer.set_style_range( + row_num - 2, + (padding as isize + span_start_pos as isize) as usize, + (padding as isize + span_end_pos as isize) as usize, + Style::Removal, + true, + ); + } } // length of the code after substitution |