docs: investigate two-column diff hatching

docs/configuration.md

@@ -185,7 +185,7 @@ With a decimal prefix, `g` instead jumps immediately to that one-based source li
 
 Normal `yy` copies complete rows without moving the carets; `dd` / `cc` delete/change complete rows; `dw` / `db` delete forward/backward word spans within each caret's current logical line, preserving newlines. `cw` / `cb` cut the same spans and enter Insert. Leading and post-operator counts multiply and word edits stop at the line end/start. Bind `config.core.copy_line`, `config.core.delete_line`, `config.core.change_line`, `config.core.delete_word_forward`, `config.core.delete_word_backward`, `config.core.change_word_forward`, or `config.core.change_word_backward` to another key or sequence for another route. A configured/disabled operator key, a configured sequence starting with that key, or choosing it as the leader overrides its built-in operator prefix. These are dedicated actions, not general operator–motion grammar.
 
-Normal `C` / `D` / `Y` change/delete/copy the cursor-to-line-end suffix through `config.core.change_to_line_end`, `config.core.delete_to_line_end`, and `config.core.copy_to_line_end`. Normal `r` waits for a literal replacement character through `config.core.replace_character`; `s` deletes the current grapheme and enters Insert through `config.core.substitute_character`. Rebinding these actions preserves their native counts, Unicode boundaries, undo, and read-only guards.
+Normal `C` / `D` / `Y` change/delete/copy the cursor-to-line-end suffix through `config.core.change_to_line_end`, `config.core.delete_to_line_end`, and `config.core.copy_to_line_end`. Normal and Visual `r` wait for a literal replacement character through `config.core.replace_character`: Normal honors the count; Visual replaces each selected grapheme without replacing newlines. Normal `s` deletes the current grapheme and enters Insert through `config.core.substitute_character`. Rebinding these actions preserves their native counts, Unicode boundaries, undo, and read-only guards.
 
 `f<char>` / `F<char>` seeks forward/backward on the current line in Normal and Visual, with counts such as `2fx`. Rebind `config.core.seek_forward` / `config.core.seek_backward` to a single key or leader sequence; the action then waits for a literal target character. For example, `config.bind "s", config.core.seek_forward` makes `2sx` seek the second following `x`. Pass `mode: config.modes.visual` to install a Visual route. These native-only actions do not have Ex commands.
 
@@ -197,7 +197,8 @@ Normal `C` / `D` / `Y` change/delete/copy the cursor-to-line-end suffix through
 | Normal, Visual | `insert_first_nonblank`, `append_line_end`, `clone_above`, `clone_below` |
 | Normal | `join_lines`, `undo`, `redo`, `command` |
 | Normal | `copy_line`, `delete_line`, `change_line` |
-| Normal | `change_to_line_end`, `delete_to_line_end`, `copy_to_line_end`, `replace_character`, `substitute_character`, `delete_word_forward`, `delete_word_backward`, `change_word_forward`, `change_word_backward` |
+| Normal | `change_to_line_end`, `delete_to_line_end`, `copy_to_line_end`, `substitute_character`, `delete_word_forward`, `delete_word_backward`, `change_word_forward`, `change_word_backward` |
+| Normal, Visual | `replace_character` |
 | Normal | `save`, `force_save`, `quit`, `force_quit`, `restart`, `force_restart`, `save_and_quit`, `force_save_and_quit`, `plugins` |
 | Normal | `edit`, `buffers`, `buffer`, `buffer_next`, `buffer_previous`, `buffer_delete`, `buffer_force_delete` |
 | Normal | `follow_link` |

docs/diff-hatching-investigation.md

@@ -0,0 +1,57 @@
+# Diff hatching: two-column diagonal feasibility
+
+## Finding
+
+**Yes: Unicode has the exact two line segments needed.** Repeat the following pair, in this order, with each character occupying one terminal column:
+
+| Position | Character | Code point | Official Unicode name |
+| --- | --- | --- | --- |
+| Left cell | 🯐 | U+1FBD0 | BOX DRAWINGS LIGHT DIAGONAL MIDDLE RIGHT TO LOWER LEFT |
+| Right cell | 🯑 | U+1FBD1 | BOX DRAWINGS LIGHT DIAGONAL UPPER RIGHT TO MIDDLE LEFT |
+
+These are listed under **Character cell diagonals** on page 6 of the [official Unicode 17.0 Symbols for Legacy Computing chart](https://www.unicode.org/Public/17.0.0/charts/PDF/U1FB00.pdf); the exact names are also in [UnicodeData.txt](https://www.unicode.org/Public/17.0.0/ucd/UnicodeData.txt). They were introduced in **Unicode 16.0** (`1FBCB..1FBEF` in [DerivedAge.txt](https://www.unicode.org/Public/17.0.0/ucd/DerivedAge.txt)). The names specify endpoints, not a drawing direction: together they join the pair's bottom-left corner to the shared edge's midpoint, then to the pair's top-right corner.
+
+Sample (glyphs may be missing or differently rendered in the Markdown viewer):
+
+```text
+🯐🯑🯐🯑🯐🯑🯐🯑
+🯐🯑🯐🯑🯐🯑🯐🯑
+```
+
+Equivalent escaped sequence: `\u{1FBD0}\u{1FBD1}`. This is two separate characters/cells, not one double-width character.
+
+## Geometry
+
+For physical cell width `W` and height `H`, the ideal joined stroke has horizontal run `2W` and vertical rise `H`, so its angle above horizontal is:
+
+```text
+θ = atan(H / (2W))
+```
+
+This is **45° iff `H = 2W`**. The current full-cell `╱` has ideal angle `atan(H / W)`; at `H = 2W`, that is approximately 63.4°. Thus the pair is shallower, but the actual angle depends on the terminal's cell dimensions, including line spacing. These are geometric deductions from the chart's endpoints, not measured rendering results.
+
+Do not substitute U+1FBA0–U+1FBAE: their centre/cell-edge endpoints describe different segments (see page 5 of the same chart). In particular, a side midpoint to top/bottom centre has run `W/2` and rise `H/2`, preserving the full-cell diagonal's slope rather than halving it.
+
+## Line segments, not filled mosaics
+
+U+1FBD0/U+1FBD1 are **light box-drawing strokes**. The chart separately labels U+1FB3C–U+1FB6F as **Smooth mosaic terminal graphic characters**: their `BLOCK DIAGONAL` names describe filled regions bounded by diagonals, not thin lines. For example, U+1FB48 is LOWER RIGHT BLOCK DIAGONAL LOWER LEFT TO LOWER MIDDLE RIGHT and U+1FB42 is LOWER RIGHT BLOCK DIAGONAL UPPER MIDDLE LEFT TO UPPER RIGHT ([chart, pages 3–4](https://www.unicode.org/Public/17.0.0/charts/PDF/U1FB00.pdf), [UnicodeData.txt](https://www.unicode.org/Public/17.0.0/ucd/UnicodeData.txt)). Those are not equivalent replacements for light hatching.
+
+## Support limits and current code
+
+- Unicode 16.0 repertoire support is a prerequisite; the existence of these characters does not establish coverage in the selected terminal/font. Missing glyphs or fallback glyphs remain possible, and fallback geometry must be checked in the intended renderer. Unicode explicitly says its chart glyph shapes are **not prescriptive** and actual fonts may vary ([chart, page 1](https://www.unicode.org/Public/17.0.0/charts/PDF/U1FB00.pdf)). Pixel-perfect joins or 45° rendering cannot be promised.
+- The pair has East Asian Width **Neutral (`N`)**, from `1FB94..1FBEF` in [EastAsianWidth.txt](https://www.unicode.org/Public/17.0.0/ucd/EastAsianWidth.txt). This is not a terminal-width guarantee: [UAX #11, §2 and §4](https://www.unicode.org/reports/tr11/) explicitly requires terminal-specific tailoring and distinguishes font/layout width from the property. Both the application and terminal must agree on one column per glyph.
+- Current rendering writes one `╱` per column with `DarkGray` foreground and reset background in [src/tui.rs:3308–3316](../src/tui.rs#L3308-L3316); the documented behavior is [docs/editing.md:426](editing.md#L426). This note proposes no implementation change. Any later cutover would need a defined pair phase and odd-width clipping behavior, plus terminal/font evidence.
+
+## Terminal support
+
+- **Ghostty 1.3.1:** The [released drawing source](https://github.com/ghostty-org/ghostty/blob/v1.3.1/src/font/sprite/draw/symbols_for_legacy_computing.zig#L1007-L1031) explicitly implements both segments with the required endpoints. Ghostty's [codepoint resolver](https://github.com/ghostty-org/ghostty/blob/main/src/font/CodepointResolver.zig#L120-L145) normally selects procedural sprite rendering before ordinary font lookup, so this does not require font coverage; explicit codepoint font overrides take precedence.
+- **Kitty:** [Current font dispatch](https://github.com/kovidgoyal/kitty/blob/master/kitty/fonts.c#L838-L886) routes this range to native box drawing, and [drawing source](https://github.com/kovidgoyal/kitty/blob/master/kitty/decorations.c#L2759-L2774) explicitly implements the two segments. This establishes support in inspected upstream source, not a minimum released version.
+- The local environment reported Herdr 0.9.3; installed binaries reported Ghostty 1.3.1 and Kitty 0.45.0. Herdr [runs inside an outer terminal](https://github.com/herdrdev/herdr), so its presence and these installations do not prove which renderer displays this session. Visual verification through the actual terminal/multiplexer remains necessary.
+
+**Recommendation:** Use the two-character text tile if it looks correct in the target terminal. No image protocol or new dependency is needed. Older/other terminals may lack glyph coverage; exact 45° remains conditional on cell geometry.
+
+## Runtime evidence
+
+An executed disposable `rustc` smoke program used the repository's actual compiled `ratatui` and `unicode-width` dependencies, a fixed viewport, `Terminal<CrosstermBackend<Vec<u8>>>`, and the same per-cell `set_symbol`/style logic as the current renderer. Both U+1FBD0 and U+1FBD1 returned width `Some(1)`. At three rows high, widths 1, 2, 3, and 12 emitted exactly 3, 6, 9, and 36 glyphs respectively: no dropped or double-width cells. This establishes application-side width/emission behavior, **not** actual terminal glyph coverage, pixel joins, or the visible angle; those were not visually verified. The disposable program and binary were removed.
+
+Investigation only: no production code changed and no TODO marked complete.

docs/editing.md

@@ -35,7 +35,8 @@ Indicators refresh asynchronously. Typing and undo/redo retain the last complete
 | Normal | `x`/Delete delete; `u` undo; `U` (Shift+u) redo; `:` enter command mode |
 | Normal | `yy` copies whole lines without moving; `dd` deletes them; `cc` changes them and enters Insert; counts work (`3yy`, `2dd`, `2cc`) |
 | Normal | `D` deletes through line end; `C` changes that suffix and enters Insert; `Y` copies that suffix characterwise |
-| Normal | `r<char>` replaces the current grapheme; `s` deletes it and enters Insert |
+| Normal, Visual | `r<char>` replaces the current grapheme in Normal or every selected grapheme in Visual |
+| Normal | `s` deletes the current grapheme and enters Insert |
 | Normal | `d<count>w` / `d<count>b` delete forward/backward word spans, e.g. `d2w` / `d2b` |
 | Normal | `c<count>w` / `c<count>b` cut the same line-local spans as `d` and enter Insert, e.g. `c2w` / `c2b` |
 | Normal, Visual | `.` repeats the last successful native edit against the current targets; one undo group |
@@ -126,6 +127,8 @@ Copy and cut return to Normal at each selection start; Visual cancellation keeps
 
 Visual `c` removes all selected text into the configured clipboard and enters Insert at each selection start. In the default System policy, clipboard publication must succeed before any deletion; failures leave text and selections intact. Deletion and replacement typing form one undo action when Insert mode is exited, including through explicit command execution. Esc without typing commits the deletion alone. An identical replacement creates no history entry and preserves redo. Changing only characterwise empty final-row selections enters Insert without overwriting either clipboard; linewise empty final rows are genuine rows and publish a newline.
 
+Visual `r<char>` replaces every selected grapheme with the literal character, preserving newline separators and the clipboard. It returns to Normal at each selection start as one undo action and supports `.` repeat. Esc while waiting for the character cancels the replacement without clearing selections. Identical replacements and newline-only selections do not add history or discard redo.
+
 Bracketed paste broadcasts the same literal text to all Insert carets in a separate undo group, distinct from typing before/after it. A rejected paste leaves the pending change intact. Normal supports counted `yy`, `dd`, `cc`, `dw`, `db`, `cw`, and `cb`, but not arbitrary operator–motion grammar; blockwise Visual is also unsupported. `c`, `d`, and `y` type literal text in Insert mode.
 
 Clipboard policy is session-wide and defaults to the system clipboard. Copy/cut store fragments in document order: one fragment broadcasts to every caret; matching fragment/caret counts pair in document order; any other count refuses paste without changing editing state. Empty clipboard paste does not edit text; copying/cutting only characterwise empty final-row selections does not overwrite either register. Linewise copy/cut retain whole-row shape, including a newline fragment for an empty final row. Open a new search or enter Ex commands after leaving Visual mode. Plugin commands execute once, not once per target: successful text effects collapse to the primary and apply once; rejected or message-only effects preserve the selection set. There is no selection-aware plugin API yet.

src/editor.rs

@@ -325,6 +325,10 @@ enum EditStart {
         target: char,
         count: usize,
     },
+    ReplaceSelection {
+        target: char,
+        selector: SelectionIntent,
+    },
     Delete,
     Join,
     Paste {
@@ -559,7 +563,7 @@ core_actions![
     (
         "core.replace_character",
         Action::ReplaceCharacter,
-        &[Mode::Normal]
+        &[Mode::Normal, Mode::Visual]
     ),
     (
         "core.substitute_character",
@@ -1165,7 +1169,6 @@ fn default_bindings() -> HashMap<Mode, HashMap<Input, Binding>> {
         ('C', ChangeToLineEnd),
         ('D', DeleteToLineEnd),
         ('Y', CopyToLineEnd),
-        ('r', ReplaceCharacter),
         ('s', SubstituteCharacter),
         ('u', Undo),
         ('U', Redo),
@@ -1218,6 +1221,7 @@ fn default_bindings() -> HashMap<Mode, HashMap<Input, Binding>> {
             ('v', Select),
             ('V', SelectLinewise),
             ('.', RepeatLastEdit),
+            ('r', ReplaceCharacter),
         ] {
             bindings
                 .entry(mode)
@@ -6217,7 +6221,7 @@ impl Editor {
         }
         if let Some((operator, prefix)) = self.line_pending.take() {
             if operator == 'r' {
-                if self.active.view.mode == Mode::Normal
+                if matches!(self.active.view.mode, Mode::Normal | Mode::Visual)
                     && let Input::Char(target) = input
                     && (!target.is_control() || target == '\t')
                 {
@@ -6225,14 +6229,24 @@ impl Editor {
                         self.set_message("Diff pane is read-only");
                     } else {
                         let before = self.snapshot();
-                        self.replace_characters(target, prefix);
-                        self.record_native(
-                            before,
-                            EditRecipe {
-                                start: EditStart::Replace {
+                        let (ranges, start) = if self.active.view.mode == Mode::Visual {
+                            let ranges = self.selections();
+                            let selector = self.selection_intent(&ranges);
+                            (ranges, EditStart::ReplaceSelection { target, selector })
+                        } else {
+                            (
+                                self.normal_ranges(Action::SubstituteCharacter, prefix),
+                                EditStart::Replace {
                                     target,
                                     count: prefix,
                                 },
+                            )
+                        };
+                        self.replace_characters(target, &ranges);
+                        self.record_native(
+                            before,
+                            EditRecipe {
+                                start,
                                 steps: Vec::new(),
                             },
                         );
@@ -8462,8 +8476,7 @@ impl Editor {
         self.reveal_caret();
     }
 
-    fn replace_characters(&mut self, replacement: char, count: usize) {
-        let ranges = self.normal_ranges(Action::SubstituteCharacter, count);
+    fn replace_characters(&mut self, replacement: char, ranges: &[Selection]) {
         let offsets = line_offsets(&self.active.lines);
         let mut bytes = [0; 4];
         let replacement: &str = replacement.encode_utf8(&mut bytes);
@@ -8471,20 +8484,52 @@ impl Editor {
             .iter()
             .enumerate()
             .filter(|(_, range)| range.start != range.end)
-            .map(|(target, range)| Edit {
-                target: Some(target),
-                start: cursor_offset(&self.active.lines, &offsets, range.start),
-                end: cursor_offset(&self.active.lines, &offsets, range.end),
-                text: if range.end.column - range.start.column == 1 {
+            .map(|(target, range)| {
+                let start = cursor_offset(&self.active.lines, &offsets, range.start);
+                let end = cursor_offset(&self.active.lines, &offsets, range.end);
+                let text = if range.start.row == range.end.row {
+                    let count = range.end.column - range.start.column;
+                    if count == 1 {
                         Cow::Borrowed(replacement)
                     } else {
-                    Cow::Owned(replacement.repeat(range.end.column - range.start.column))
-                },
+                        Cow::Owned(replacement.repeat(count))
+                    }
+                } else {
+                    let mut text = String::with_capacity(end - start);
+                    for row in range.start.row..=range.end.row {
+                        let first = if row == range.start.row {
+                            range.start.column
+                        } else {
+                            0
+                        };
+                        let last = if row == range.end.row {
+                            range.end.column
+                        } else {
+                            grapheme_count(&self.active.lines[row])
+                        };
+                        text.reserve((last - first) * replacement.len());
+                        for _ in first..last {
+                            text.push_str(replacement);
+                        }
+                        if row < range.end.row {
+                            text.push('\n');
+                        }
+                    }
+                    Cow::Owned(text)
+                };
+                Edit {
+                    target: Some(target),
+                    start,
+                    end,
+                    text,
                     caret: 0,
                     round_up: false,
+                }
             })
             .collect();
         self.apply_edits(edits);
+        self.active.view.visual_motions = None;
+        self.active.view.linewise = false;
         self.active.view.mode = Mode::Normal;
         self.normalize_targets();
     }
@@ -9021,10 +9066,18 @@ impl Editor {
             EditStart::Selection {
                 selector: SelectionIntent::Spans(spans),
                 ..
+            }
+            | EditStart::ReplaceSelection {
+                selector: SelectionIntent::Spans(spans),
+                ..
             } if self.active.view.mode != Mode::Visual => Some(spans.len()),
             EditStart::Selection {
                 selector: SelectionIntent::Rows(rows),
                 ..
+            }
+            | EditStart::ReplaceSelection {
+                selector: SelectionIntent::Rows(rows),
+                ..
             } if self.active.view.mode != Mode::Visual => Some(rows.len()),
             _ => None,
         };
@@ -9117,7 +9170,14 @@ impl Editor {
                     self.normalize_targets();
                 }
             }
-            EditStart::Replace { target, count } => self.replace_characters(*target, *count),
+            EditStart::Replace { target, count } => {
+                let ranges = self.normal_ranges(Action::SubstituteCharacter, *count);
+                self.replace_characters(*target, &ranges);
+            }
+            EditStart::ReplaceSelection { target, selector } => {
+                let ranges = self.replay_ranges(selector);
+                self.replace_characters(*target, &ranges);
+            }
             EditStart::Lines { change, count } => {
                 let ranges = self.line_selections(*count);
                 clipboard = Some((self.selection_fragments(&ranges), true));
@@ -19937,6 +19997,43 @@ mod tests {
         }
     }
 
+    #[test]
+    fn readonly_visual_replacement_preserves_snapshot_selections_and_history() {
+        let directory = Directory::new();
+        let mut editor = editor();
+        historical_diff(
+            &mut editor,
+            &directory.0,
+            vec!["one two three".into()],
+            vec!["four five six".into()],
+        );
+        for focus in [Focus::Before, Focus::After] {
+            if editor.diff().unwrap().focus != focus {
+                editor.handle(Input::Char('\t'));
+            }
+            type_text(&mut editor, "vl");
+            let text = editor.context().text;
+            let targets = editor.active.view.targets.clone();
+            let undo = editor.active.undo.len();
+            let clipboard = editor.clipboard.clone();
+            for pending in [false, true] {
+                if pending {
+                    editor.line_pending = Some(('r', 1));
+                } else {
+                    editor.handle(Input::Char('r'));
+                }
+                editor.handle(Input::Char('X'));
+                assert_eq!(editor.context().text, text);
+                assert_eq!(editor.active.view.targets, targets);
+                assert_eq!(editor.mode(), Mode::Visual);
+                assert_eq!(editor.line_operator_pending(), None);
+                assert_eq!(editor.clipboard, clipboard);
+                assert_eq!(editor.active.undo.len(), undo);
+            }
+            editor.handle(Input::Escape);
+        }
+    }
+
     fn set_carets(editor: &mut Editor, positions: &[(usize, usize)], primary: usize) {
         editor.active.view.mode = Mode::Normal;
         editor.active.view.visual_motions = None;

src/main.rs

@@ -38,6 +38,7 @@ Normal: i/a insert, I/A insert at first nonblank/end, o/O new line
         y/d/c/p/P use the system clipboard by default; config.clipboard_mode = \"separate\" isolates it
         Esc keeps only the primary caret
 Visual: motions extend selections, y copy, d/x/Delete cut, c change
+        r<char> replaces every selected grapheme, preserving newlines; one undo action
         I/A insert at each selected line's first nonblank/end
         Ctrl+l split rows, Ctrl+n add occurrence, Ctrl+s skip, Ctrl+a all
         v/V switches selection shape; same selector or Esc cancels retaining carets

tests/normal_editing.rs

@@ -42,6 +42,89 @@ fn keys(editor: &mut Editor, text: &str) {
     }
 }
 
+#[test]
+fn visual_r_replaces_selected_graphemes_as_one_undo_edit() {
+    let fixture = Fixture::new();
+    let source = "ae\u{301}👩‍🚀z\nrest\n";
+    let mut editor = fixture.editor(source);
+    keys(&mut editor, "lv2l");
+    assert_eq!(editor.mode(), Mode::Visual);
+    keys(&mut editor, "r界");
+    assert_eq!(editor.context().text, "a界界界\nrest\n");
+    assert_eq!(editor.mode(), Mode::Normal);
+    keys(&mut editor, "u");
+    assert_eq!(editor.context().text, source);
+    assert!(!editor.dirty());
+    keys(&mut editor, "U");
+    assert_eq!(editor.context().text, "a界界界\nrest\n");
+}
+
+#[test]
+fn visual_r_preserves_selected_newlines_in_both_directions_and_shapes() {
+    for (source, selection, expected) in [
+        ("ae\u{301}👩‍🚀z\n\nbc\nlast\n", "v2j", "QQQQ\n\nQc\nlast\n"),
+        ("ae\u{301}👩‍🚀z\n\nbc\nlast\n", "2jv2k", "QQQQ\n\nQc\nlast\n"),
+        ("ae\u{301}👩‍🚀z\n\nbc\nlast\n", "V2j", "QQQQ\n\nQQ\nlast\n"),
+        ("ab\ncd", "Vj", "QQ\nQQ"),
+        ("\n\n", "Vj", "\n\n"),
+    ] {
+        let fixture = Fixture::new();
+        let mut editor = fixture.editor(source);
+        keys(&mut editor, selection);
+        keys(&mut editor, "rQ");
+        assert_eq!(editor.context().text, expected, "{selection}");
+        assert_eq!(editor.mode(), Mode::Normal);
+        assert_eq!(editor.dirty(), source != expected);
+        keys(&mut editor, "u");
+        assert_eq!(editor.context().text, source);
+    }
+}
+
+#[test]
+fn visual_r_replaces_every_selection_and_restores_carets_on_undo() {
+    let fixture = Fixture::new();
+    let source = "abcd\nwxyz\n";
+    let mut editor = fixture.editor(source);
+    keys(&mut editor, "vl");
+    editor.handle(Input::Ctrl('e'));
+    let carets = editor.carets();
+    assert_eq!(editor.selection_count(), 2);
+    keys(&mut editor, "r界");
+    assert_eq!(editor.context().text, "界界cd\n界界yz\n");
+    assert_eq!(editor.selection_count(), 2);
+    keys(&mut editor, "u");
+    assert_eq!(editor.context().text, source);
+    assert_eq!(editor.carets(), carets);
+}
+
+#[test]
+fn visual_r_repeats_selection_intent_without_overwriting_the_clipboard() {
+    let fixture = Fixture::new();
+    let mut editor = fixture.editor("abc\nuvwxyz\n");
+    keys(&mut editor, "yyvlrQj0.");
+    assert_eq!(editor.context().text, "QQc\nQQwxyz\n");
+    keys(&mut editor, "4lv.");
+    assert_eq!(editor.context().text, "QQc\nQQwxQz\n");
+    keys(&mut editor, "P");
+    assert_eq!(editor.context().text, "QQc\nabc\nQQwxQz\n");
+}
+
+#[test]
+fn cancelled_and_identical_visual_replacements_preserve_redo() {
+    let fixture = Fixture::new();
+    let mut editor = fixture.editor("abc\n");
+    keys(&mut editor, "rQulvr");
+    editor.handle(Input::Escape);
+    assert_eq!(editor.mode(), Mode::Visual);
+    assert_eq!(editor.line_operator_pending(), None);
+    keys(&mut editor, "rb");
+    assert_eq!(editor.context().text, "abc\n");
+    assert_eq!(editor.mode(), Mode::Normal);
+    assert!(!editor.dirty());
+    keys(&mut editor, "U");
+    assert_eq!(editor.context().text, "Qbc\n");
+}
+
 #[test]
 fn change_and_delete_line_suffix_preserve_newlines_and_group_insert_undo() {
     for operation in ["C", "D", "9C", "9D"] {