feat(tvix/eval): track pattern binding names r/7448

These need to be preserved at least for builtins.toXML.

Also, we incorrectly only wrote an <attrspat> in case ellipsis was true,
but that's not the case.

Change-Id: I6bff9c47c2922f878d5c43e48280cda9c9ddb692
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10686
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: aspen <root@gws.fyi>

1 files changed, 9 insertions, 2 deletions

diff --git a/tvix/eval/src/builtins/to_xml.rs b/tvix/eval/src/builtins/to_xml.rs
index 250891b60d99..f23cb22db3d9 100644
--- a/tvix/eval/src/builtins/to_xml.rs
+++ b/tvix/eval/src/builtins/to_xml.rs
@@ -90,15 +90,22 @@ fn value_variant_to_xml<W: Write>(w: &mut EventWriter<W>, value: &Value) -> Resu
 
             match &c.lambda.formals {
                 Some(formals) => {
+                    let mut attrspat = XmlEvent::start_element("attrspat");
                     if formals.ellipsis {
-                        w.write(XmlEvent::start_element("attrspat").attr("ellipsis", "1"))?;
-                        w.write(XmlEvent::end_element())?;
+                        attrspat = attrspat.attr("ellipsis", "1");
+                    }
+                    if let Some(ref name) = &formals.name {
+                        attrspat = attrspat.attr("name", name.as_str());
                     }
 
+                    w.write(attrspat)?;
+
                     for arg in formals.arguments.iter() {
                         w.write(XmlEvent::start_element("attr").attr("name", arg.0.as_str()))?;
                         w.write(XmlEvent::end_element())?;
                     }
+
+                    w.write(XmlEvent::end_element())?;
                 }
                 None => {
                     // TODO(tazjin): tvix does not currently persist function