add doc comment for ActiveArgument enum

Author: aaron-ang

pyrefly/lib/state/lsp.rs

@@ -86,13 +86,6 @@ use crate::types::callable::Params;
 use crate::types::module::ModuleType;
 use crate::types::types::Type;
 
-#[derive(Debug, Clone)]
-enum ActiveArgument {
-    Positional(usize),
-    Keyword(Name),
-    Next(usize),
-}
-
 fn default_true() -> bool {
     true
 }
@@ -481,6 +474,14 @@ pub struct FindDefinitionItem {
     pub module: Module,
 }
 
+/// The currently active argument in a function call for signature help.
+#[derive(Debug)]
+enum ActiveArgument {
+    Positional(usize),
+    Keyword(Name),
+    Next(usize),
+}
+
 impl<'a> Transaction<'a> {
     fn get_type(&self, handle: &Handle, key: &Key) -> Option<Type> {
         let idx = self.get_bindings(handle)?.key_to_idx(key);
@@ -872,7 +873,7 @@ impl<'a> Transaction<'a> {
                 }
             }
             // Check keyword arguments
-            let positional_count = call.arguments.args.len();
+            let kwarg_start_idx = call.arguments.args.len();
             for (j, kw) in call.arguments.keywords.iter().enumerate() {
                 if kw.range.contains_inclusive(find) {
                     Self::visit_finding_signature_range(&kw.value, find, res);
@@ -881,7 +882,7 @@ impl<'a> Transaction<'a> {
                     }
                     let active_argument = match kw.arg.as_ref() {
                         Some(identifier) => ActiveArgument::Keyword(identifier.id.clone()),
-                        None => ActiveArgument::Positional(positional_count + j),
+                        None => ActiveArgument::Positional(kwarg_start_idx + j),
                     };
                     *res = Some((call.func.range(), call.arguments.range, active_argument));
                     return;