Add Layer<Validation>::take_errors

It is an improvement over `into_result` as it doesn't require dropping
the validation layer.

crates/fj-core/src/layers/validation.rs

@@ -8,6 +8,11 @@ use crate::{
 use super::{objects::InsertObject, Command, Event, Layer};
 
 impl Layer<Validation> {
+    /// Take all errors stored in the validation layer
+    pub fn take_errors(&mut self) -> Result<(), ValidationErrors> {
+        self.process(TakeErrors, &mut Vec::new())
+    }
+
     /// Consume the validation layer, returning any validation errors
     pub fn into_result(self) -> Result<(), ValidationErrors> {
         let errors = self.into_state().into_errors();

crates/fj-core/src/validate/solid.rs

@@ -236,7 +236,7 @@ mod tests {
         valid_solid.validate_and_return_first_error()?;
 
         // Ignore remaining validation errors.
-        let _ = core.layers.validation.into_result();
+        let _ = core.layers.validation.take_errors();
 
         Ok(())
     }
@@ -289,7 +289,7 @@ mod tests {
         valid_solid.validate_and_return_first_error()?;
 
         // Ignore remaining validation errors.
-        let _ = core.layers.validation.into_result();
+        let _ = core.layers.validation.take_errors();
 
         Ok(())
     }
@@ -339,7 +339,7 @@ mod tests {
         valid_solid.validate_and_return_first_error()?;
 
         // Ignore remaining validation errors.
-        let _ = core.layers.validation.into_result();
+        let _ = core.layers.validation.take_errors();
 
         Ok(())
     }
@@ -379,7 +379,7 @@ mod tests {
         valid_solid.validate_and_return_first_error()?;
 
         // Ignore remaining validation errors.
-        let _ = core.layers.validation.into_result();
+        let _ = core.layers.validation.take_errors();
 
         Ok(())
     }

crates/fj/src/handle_model.rs

@@ -23,7 +23,7 @@ use crate::Args;
 ///
 /// This function is used by Fornjot's own testing infrastructure, but is useful
 /// beyond that, when using Fornjot directly to define a model.
-pub fn handle_model<M>(model: &M, core: Instance) -> Result
+pub fn handle_model<M>(model: &M, mut core: Instance) -> Result
 where
     for<'r> (&'r M, Tolerance): Triangulate,
     M: BoundingVolume<3>,
@@ -36,7 +36,7 @@ where
     let args = Args::parse();
 
     if !args.ignore_validation {
-        core.layers.validation.into_result()?;
+        core.layers.validation.take_errors()?;
     }
 
     let aabb = model.aabb().unwrap_or(Aabb {