Fix square base

library/src/layout/grid.rs

@@ -321,7 +321,7 @@ impl<'a, 'v> GridLayouter<'a, 'v> {
         let rcols = vec![Abs::zero(); cols.len()];
         let lrows = vec![];
 
-        // We use the regions for auto row measurement. Since at that moment,
+        // We use these regions for auto row measurement. Since at that moment,
         // columns are already sized, we can enable horizontal expansion.
         let mut regions = regions.clone();
         regions.expand = Axes::new(true, false);

library/src/visualize/shape.rs

@@ -556,7 +556,7 @@ fn layout(
         // Pad the child.
         let child = child.clone().padded(inset.map(|side| side.map(Length::from)));
 
-        let mut pod = Regions::one(regions.first, regions.base, regions.expand);
+        let pod = Regions::one(regions.first, regions.base, regions.expand);
         frame = child.layout(vt, styles, pod)?.into_frame();
 
         // Relayout with full expansion into square region to make sure
@@ -571,8 +571,8 @@ fn layout(
                 desired.min(regions.first.x).min(regions.first.y)
             };
 
-            pod.first = Size::splat(length);
-            pod.expand = Axes::splat(true);
+            let size = Size::splat(length);
+            let pod = Regions::one(size, size, Axes::splat(true));
             frame = child.layout(vt, styles, pod)?.into_frame();
         }
     } else {

tests/typ/bugs/square-base.typ

@@ -0,0 +1,5 @@
+// Test that square sets correct base for its content.
+
+---
+#set page(height: 80pt)
+#square(width: 40%, rect(width: 60%, height: 80%))