Fix math.root frame size (#6021)

crates/typst-ide/src/analyze.rs

@@ -26,7 +26,7 @@ pub fn analyze_expr(
         ast::Expr::Str(v) => Value::Str(v.get().into()),
         _ => {
             if node.kind() == SyntaxKind::Contextual {
-                if let Some(child) = node.children().last() {
+                if let Some(child) = node.children().next_back() {
                     return analyze_expr(world, &child);
                 }
             }

crates/typst-layout/src/flow/compose.rs

@@ -115,7 +115,7 @@ impl<'a, 'b> Composer<'a, 'b, '_, '_> {
         let column_height = regions.size.y;
         let backlog: Vec<_> = std::iter::once(&column_height)
             .chain(regions.backlog)
-            .flat_map(|&h| std::iter::repeat(h).take(self.config.columns.count))
+            .flat_map(|&h| std::iter::repeat_n(h, self.config.columns.count))
             .skip(1)
             .collect();
 

crates/typst-layout/src/grid/layouter.rs

@@ -1469,7 +1469,7 @@ impl<'a> GridLayouter<'a> {
                 // last height is the one for the current region.
                 rowspan
                     .heights
-                    .extend(std::iter::repeat(Abs::zero()).take(amount_missing_heights));
+                    .extend(std::iter::repeat_n(Abs::zero(), amount_missing_heights));
 
                 // Ensure that, in this region, the rowspan will span at least
                 // this row.

crates/typst-layout/src/math/root.rs

@@ -85,14 +85,15 @@ pub fn layout_root(
         ascent.set_max(shift_up + index.ascent());
     }
 
-    let radicand_x = sqrt_offset + sqrt.width();
+    let sqrt_x = sqrt_offset.max(Abs::zero());
+    let radicand_x = sqrt_x + sqrt.width();
     let radicand_y = ascent - radicand.ascent();
     let width = radicand_x + radicand.width();
     let size = Size::new(width, ascent + descent);
 
     // The extra "- thickness" comes from the fact that the sqrt is placed
     // in `push_frame` with respect to its top, not its baseline.
-    let sqrt_pos = Point::new(sqrt_offset, radicand_y - gap - thickness);
+    let sqrt_pos = Point::new(sqrt_x, radicand_y - gap - thickness);
     let line_pos = Point::new(radicand_x, radicand_y - gap - (thickness / 2.0));
     let radicand_pos = Point::new(radicand_x, radicand_y);
 
@@ -100,7 +101,8 @@ pub fn layout_root(
     frame.set_baseline(ascent);
 
     if let Some(index) = index {
-        let index_pos = Point::new(kern_before, ascent - index.ascent() - shift_up);
+        let index_x = -sqrt_offset.min(Abs::zero()) + kern_before;
+        let index_pos = Point::new(index_x, ascent - index.ascent() - shift_up);
         frame.push_frame(index_pos, index);
     }
 

crates/typst-layout/src/math/stretch.rs

@@ -302,6 +302,6 @@ fn assemble(
 fn parts(assembly: GlyphAssembly, repeat: usize) -> impl Iterator<Item = GlyphPart> + '_ {
     assembly.parts.into_iter().flat_map(move |part| {
         let count = if part.part_flags.extender() { repeat } else { 1 };
-        std::iter::repeat(part).take(count)
+        std::iter::repeat_n(part, count)
     })
 }

crates/typst-library/src/model/numbering.rs

@@ -394,7 +394,7 @@ impl NumberingKind {
                 const SYMBOLS: &[char] = &['*', '†', '‡', '§', '¶', '‖'];
                 let symbol = SYMBOLS[(n - 1) % SYMBOLS.len()];
                 let amount = ((n - 1) / SYMBOLS.len()) + 1;
-                std::iter::repeat(symbol).take(amount).collect()
+                std::iter::repeat_n(symbol, amount).collect()
             }
             Self::Hebrew => hebrew_numeral(n),
 

crates/typst-library/src/visualize/gradient.rs

@@ -574,8 +574,7 @@ impl Gradient {
         }
 
         let n = repetitions.v;
-        let mut stops = std::iter::repeat(self.stops_ref())
-            .take(n)
+        let mut stops = std::iter::repeat_n(self.stops_ref(), n)
             .enumerate()
             .flat_map(|(i, stops)| {
                 let mut stops = stops

crates/typst-render/src/shape.rs

@@ -69,9 +69,11 @@ pub fn render_shape(canvas: &mut sk::Pixmap, state: State, shape: &Shape) -> Opt
             let dash = dash.as_ref().and_then(to_sk_dash_pattern);
 
             let bbox = shape.geometry.bbox_size();
-            let offset_bbox = (!matches!(shape.geometry, Geometry::Line(..)))
-                .then(|| offset_bounding_box(bbox, *thickness))
-                .unwrap_or(bbox);
+            let offset_bbox = if !matches!(shape.geometry, Geometry::Line(..)) {
+                offset_bounding_box(bbox, *thickness)
+            } else {
+                bbox
+            };
 
             let fill_transform =
                 (!matches!(shape.geometry, Geometry::Line(..))).then(|| {

tests/suite/math/root.typ

@@ -44,3 +44,9 @@ $ root(2, x) quad
 $ √2^3 = sqrt(2^3) $
 $ √(x+y) quad ∛x quad ∜x $
 $ (√2+3) = (sqrt(2)+3) $
+
+--- math-root-frame-size-index ---
+// Test size of final frame when there is an index.
+$ a root(, 3)         & a root(., 3) \
+  a sqrt(3)           & a root(2, 3) \
+  a root(#h(-1em), 3) & a root(123, 3) $