Fix weak spacing broken in math (#1966)

2 files changed, 19 insertions, 5 deletions

diff --git a/crates/typst-library/src/math/mod.rs b/crates/typst-library/src/math/mod.rs
index 1f87ff81..40df524f 100644
--- a/crates/typst-library/src/math/mod.rs
+++ b/crates/typst-library/src/math/mod.rs
@@ -418,11 +418,12 @@ impl LayoutMath for Content {
             return realized.layout_math(ctx);
         }
 
-        if let Some(children) = self.to_sequence() {
+        if self.is_sequence() {
             let mut bb = BehavedBuilder::new();
-            for child in children {
-                bb.push(child.clone(), StyleChain::default());
-            }
+            self.sequence_recursive_for_each(&mut |child: &Content| {
+                bb.push(child.clone(), StyleChain::default())
+            });
+
             for (child, _) in bb.finish().0.iter() {
                 child.layout_math(ctx)?;
             }
diff --git a/crates/typst/src/model/content.rs b/crates/typst/src/model/content.rs
index 0c79d02c..f1600f25 100644
--- a/crates/typst/src/model/content.rs
+++ b/crates/typst/src/model/content.rs
@@ -85,12 +85,25 @@ impl Content {
 
     /// Access the children if this is a sequence.
     pub fn to_sequence(&self) -> Option<impl Iterator<Item = &Self>> {
-        if !self.is::<SequenceElem>() {
+        if !self.is_sequence() {
             return None;
         }
         Some(self.attrs.iter().filter_map(Attr::child))
     }
 
+    pub fn is_sequence(&self) -> bool {
+        self.is::<SequenceElem>()
+    }
+
+    /// Also auto expands sequence of sequences into flat sequence
+    pub fn sequence_recursive_for_each(&self, f: &mut impl FnMut(&Self)) {
+        if let Some(childs) = self.to_sequence() {
+            childs.for_each(|c| c.sequence_recursive_for_each(f));
+        } else {
+            f(self);
+        }
+    }
+
     /// Access the child and styles.
     pub fn to_styled(&self) -> Option<(&Content, &Styles)> {
         if !self.is::<StyledElem>() {