// Find the bounding span.
let lo = substitution.parts.iter().map(|part| part.span.lo()).min().unwrap();
- let hi = substitution.parts.iter().map(|part| part.span.hi()).min().unwrap();
+ let hi = substitution.parts.iter().map(|part| part.span.hi()).max().unwrap();
let bounding_span = Span::with_root_ctxt(lo, hi);
let lines = cm.span_to_lines(bounding_span).unwrap();
assert!(!lines.lines.is_empty());