Modified undeclared polymorph error in structures to mention the first encountered polymorph when multiple are missing

Author: IsaacShelton

Diff for: src/resolve/type_definition/resolve.rs

@@ -123,10 +123,11 @@ fn resolve_structure(
         let mut ok = Ok(());
         ty.kind.for_each_polymorph(&mut |name| {
             if structure.params.params.keys().filter(|n| *n == name).next().is_none() {
-                ok = Err(ResolveError::other(format!("Cannot use polymorph '${}' inside type that is not declared by enclosing structure", name), ty.source));
+                if ok.is_ok() {
+                    ok = Err(ResolveError::other(format!("Cannot use polymorph '${}' inside type that is not declared by enclosing structure", name), ty.source));
+                }
             }
         });
-
         ok?;
 
         let resolved_struct = asg.structs.get_mut(struct_ref).expect("valid struct");