Change style of `infer_surface_form`

crates/fj-kernel/src/builder/vertex.rs

@@ -11,11 +11,11 @@ use crate::{
 /// Builder API for [`PartialVertex`]
 pub trait VertexBuilder {
     /// Remove the surface form of the partial vertex, inferring it on build
-    fn infer_surface_form(self) -> Self;
+    fn infer_surface_form(&mut self) -> &mut Self;
 }
 
 impl VertexBuilder for PartialVertex {
-    fn infer_surface_form(mut self) -> Self {
+    fn infer_surface_form(&mut self) -> &mut Self {
         self.surface_form = PartialSurfaceVertex::default().into();
         self
     }

crates/fj-kernel/src/validate/cycle.rs

@@ -95,7 +95,8 @@ mod tests {
 
             // Sever connection between the last and first half-edge in the
             // cycle.
-            let first_vertex = first_vertex.into_partial().infer_surface_form();
+            let mut first_vertex = first_vertex.into_partial();
+            first_vertex.infer_surface_form();
             *first_half_edge = first_half_edge
                 .clone()
                 .with_back_vertex(first_vertex)

crates/fj-kernel/src/validate/edge.rs

@@ -308,10 +308,8 @@ mod tests {
                 |vertex| -> anyhow::Result<_, ValidationError> {
                     let mut vertex = vertex.to_partial();
                     vertex.position = Some([0.].into());
-                    Ok(vertex
+                    vertex.infer_surface_form();
-                        .infer_surface_form()
+                    Ok(vertex.build(&objects)?.insert(&objects)?)
-                        .build(&objects)?
-                        .insert(&objects)?)
                 },
             )?,
             valid.global_form().clone(),