Support fractional width for `box`

1 files changed, 1 insertions, 1 deletions

diff --git a/src/doc.rs b/src/doc.rs
index 9fbd9436..64f7ae91 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -86,7 +86,7 @@ impl Frame {
     }
 
     /// Whether the frame has a non-default baseline.
-    pub fn has_baseline(&mut self) -> bool {
+    pub fn has_baseline(&self) -> bool {
         self.baseline.is_some()
     }