Fix realize in math

library/src/math/fragment.rs

@@ -148,6 +148,7 @@ pub struct GlyphFragment {
     pub font_size: Abs,
     pub class: Option<MathClass>,
     pub span: Span,
+    pub meta: Vec<Meta>,
 }
 
 impl GlyphFragment {
@@ -194,6 +195,7 @@ impl GlyphFragment {
                 _ => unicode_math_class::class(c),
             },
             span,
+            meta: MetaElem::data_in(ctx.styles()),
         }
     }
 
@@ -231,6 +233,7 @@ impl GlyphFragment {
         };
         let size = Size::new(self.width, self.ascent + self.descent);
         let mut frame = Frame::new(size);
+        frame.meta_iter(self.meta);
         frame.set_baseline(self.ascent);
         frame.push(Point::with_y(self.ascent), FrameItem::Text(item));
         frame
@@ -273,8 +276,9 @@ pub struct FrameFragment {
 }
 
 impl FrameFragment {
-    pub fn new(ctx: &MathContext, frame: Frame) -> Self {
+    pub fn new(ctx: &MathContext, mut frame: Frame) -> Self {
         let base_ascent = frame.ascent();
+        frame.meta(ctx.styles(), false);
         Self {
             frame,
             font_size: ctx.size,

library/src/math/mod.rs

@@ -344,9 +344,18 @@ impl LayoutMath for EquationElem {
 
 impl LayoutMath for Content {
     fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> {
+        // Directly layout the body of nested equations instead of handling it
+        // like a normal equation so that things like this work:
+        // ```
+        // #let my = $pi$
+        // $ my r^2 $
+        // ```
+        if let Some(elem) = self.to::<EquationElem>() {
+            return elem.layout_math(ctx);
+        }
+
         if let Some(realized) = ctx.realize(self)? {
-            realized.layout_math(ctx)?;
-            return Ok(());
+            return realized.layout_math(ctx);
         }
 
         if let Some(children) = self.to_sequence() {

library/src/math/stretch.rs

@@ -162,6 +162,7 @@ fn assemble(
     let mut frame = Frame::new(size);
     let mut offset = Abs::zero();
     frame.set_baseline(baseline);
+    frame.meta_iter(base.meta);
 
     for (fragment, advance) in selected {
         let pos = if horizontal {

src/doc.rs

@@ -273,13 +273,18 @@ impl Frame {
     /// Attach the metadata from this style chain to the frame.
     pub fn meta(&mut self, styles: StyleChain, force: bool) {
         if force || !self.is_empty() {
-            for meta in MetaElem::data_in(styles) {
-                if matches!(meta, Meta::Hide) {
-                    self.clear();
-                    break;
-                }
-                self.prepend(Point::zero(), FrameItem::Meta(meta, self.size));
+            self.meta_iter(MetaElem::data_in(styles));
+        }
+    }
+
+    /// Attach metadata from an iterator.
+    pub fn meta_iter(&mut self, iter: impl IntoIterator<Item = Meta>) {
+        for meta in iter {
+            if matches!(meta, Meta::Hide) {
+                self.clear();
+                break;
             }
+            self.prepend(Point::zero(), FrameItem::Meta(meta, self.size));
         }
     }
 

tests/typ/bugs/math-realize.typ

@@ -0,0 +1,15 @@
+// Test that content in math can be realized without breaking
+// nested equations.
+
+---
+#let my = $pi$
+#let f1 = box(baseline: 10pt, [f])
+#let f2 = style(sty => f1)
+#show math.vec: [nope]
+
+$ pi a $
+$ my a $
+$ 1 + sqrt(x/2) + sqrt(#hide($x/2$)) $
+$ a x #link("url", $+ b$) $
+$ f f1 f2 $
+$ vec(1,2) * 2 $