Generate bindings for indexed struct properties

This allows to export fields of tuple-like structs as indexed JS properties.

crates/backend/src/ast.rs

@@ -227,7 +227,7 @@ pub struct Struct {
 #[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 #[derive(Clone)]
 pub struct StructField {
-    pub name: Ident,
+    pub name: syn::Member,
     pub struct_name: Ident,
     pub readonly: bool,
     pub ty: syn::Type,

crates/backend/src/encode.rs

@@ -332,7 +332,10 @@ fn shared_struct<'a>(s: &'a ast::Struct, intern: &'a Interner) -> Struct<'a> {
 
 fn shared_struct_field<'a>(s: &'a ast::StructField, intern: &'a Interner) -> StructField<'a> {
     StructField {
-        name: intern.intern(&s.name),
+        name: match &s.name {
+            syn::Member::Named(ident) => intern.intern(ident),
+            syn::Member::Unnamed(index) => intern.intern_str(&index.index.to_string()),
+        },
         readonly: s.readonly,
         comments: s.comments.iter().map(|s| &**s).collect(),
     }