message: Fix crash when copying out of bounds selections
  Fixes
diff: @@ -11,7 +11,7 @@ use std::ops::{Bound, Range, RangeBounds};
  use crate::ansi::CursorShape;
  use crate::grid::{Dimensions, GridCell, Indexed};
  -use crate::index::{Column, Line, Point, Side};
  +use crate::index::{Boundary, Column, Line, Point, Side};
  use crate::term::cell::{Cell, Flags};
  use crate::term::{RenderableCursor, Term};
  @@ -274,6 +274,12 @@ impl Selection {
  mem::swap(&mut start, &mut end);
  }
  + // Clamp selection to within grid boundaries.
  + if end.point.line < term.topmost_line() {
  + return None;
  + }
  + start.point = start.point.grid_clamp(term, Boundary::Grid);
  +
  match self.ty {
  SelectionType::Simple => self.range_simple(start, end, columns),
  SelectionType::Block => self.range_block(start, end),
  @@ -507,11 +513,11 @@ mod tests {
  let mut selection =
  Selection::new(SelectionType::Lines, Point::new(Line(9), Column(1)), Side::Left);
  selection.update(Point::new(Line(4), Column(1)), Side::Right);
  - selection = selection.rotate(&size, &(Line(0)..Line(size.0 as i32)), 7).unwrap();
  + selection = selection.rotate(&size, &(Line(0)..Line(size.0 as i32)), 4).unwrap();
  assert_eq!(selection.to_range(&term(size.0, size.1)).unwrap(), SelectionRange {
  - start: Point::new(Line(-3), Column(0)),
  - end: Point::new(Line(2), Column(4)),
  + start: Point::new(Line(0), Column(0)),
  + end: Point::new(Line(5), Column(4)),
  is_block: false,
  });
  }
  @@ -537,11 +543,11 @@ mod tests {
  let mut selection =
  Selection::new(SelectionType::Simple, Point::new(Line(9), Column(3)), Side::Right);
  selection.update(Point::new(Line(4), Column(1)), Side::Right);
  - selection = selection.rotate(&size, &(Line(0)..Line(size.0 as i32)), 7).unwrap();
  + selection = selection.rotate(&size, &(Line(0)..Line(size.0 as i32)), 4).unwrap();
  assert_eq!(selection.to_range(&term(size.0, size.1)).unwrap(), SelectionRange {
  - start: Point::new(Line(-3), Column(2)),
  - end: Point::new(Line(2), Column(3)),
  + start: Point::new(Line(0), Column(2)),
  + end: Point::new(Line(5), Column(3)),
  is_block: false,
  });
  }
  @@ -552,11 +558,11 @@ mod tests {
  let mut selection =
  Selection::new(SelectionType::Block, Point::new(Line(9), Column(3)), Side::Right);
  selection.update(Point::new(Line(4), Column(1)), Side::Right);
  - selection = selection.rotate(&size, &(Line(0)..Line(size.0 as i32)), 7).unwrap();
  + selection = selection.rotate(&size, &(Line(0)..Line(size.0 as i32)), 4).unwrap();
  assert_eq!(selection.to_range(&term(size.0, size.1)).unwrap(), SelectionRange {
  - start: Point::new(Line(-3), Column(2)),
  - end: Point::new(Line(2), Column(3)),
  + start: Point::new(Line(0), Column(2)),
  + end: Point::new(Line(5), Column(3)),
  is_block: true
  });
  }
  