Fix fold order for vectors (#3496)

crates/typst/src/foundations/styles.rs

@@ -731,16 +731,16 @@ impl<T: Fold> Fold for Option<T> {
 }
 
 impl<T> Fold for Vec<T> {
-    fn fold(mut self, outer: Self) -> Self {
-        self.extend(outer);
-        self
+    fn fold(self, mut outer: Self) -> Self {
+        outer.extend(self);
+        outer
     }
 }
 
 impl<T, const N: usize> Fold for SmallVec<[T; N]> {
-    fn fold(mut self, outer: Self) -> Self {
-        self.extend(outer);
-        self
+    fn fold(self, mut outer: Self) -> Self {
+        outer.extend(self);
+        outer
     }
 }
 

crates/typst/src/model/enum.rs

@@ -230,7 +230,6 @@ impl LayoutMultiple for Packed<EnumElem> {
         let mut cells = vec![];
         let mut number = self.start(styles);
         let mut parents = EnumElem::parents_in(styles);
-        parents.reverse();
 
         let full = self.full(styles);
 

tests/typ/bugs/fold-vector.typ

@@ -0,0 +1,20 @@
+// Test fold order of vectors.
+
+---
+#set text(features: (liga: 1))
+#set text(features: (liga: 0))
+fi
+
+---
+#underline(stroke: aqua + 4pt)[
+  #underline[Hello]
+]
+
+---
+#let c = counter("mycounter")
+#c.update(1)
+#locate(loc => [
+  #c.update(2)
+  #c.at(loc) \
+  Second: #locate(loc => c.at(loc))
+])