Optimize arguments

Author: charliermarsh

parser/src/function.rs

@@ -21,7 +21,13 @@ type ParameterDef = (ast::Arg, Option<ast::Expr>);
 pub(crate) fn validate_arguments(
     arguments: ast::Arguments,
 ) -> Result<ast::Arguments, LexicalError> {
-    let mut all_args: Vec<&ast::Arg> = vec![];
+    let mut all_args: Vec<&ast::Arg> = Vec::with_capacity(
+        arguments.posonlyargs.len()
+            + arguments.args.len()
+            + arguments.vararg.is_some() as usize
+            + arguments.kwonlyargs.len()
+            + arguments.kwarg.is_some() as usize,
+    );
 
     all_args.extend(arguments.posonlyargs.iter());
     all_args.extend(arguments.args.iter());
@@ -36,11 +42,11 @@ pub(crate) fn validate_arguments(
         all_args.push(a);
     }
 
-    let mut all_arg_names = FxHashSet::with_hasher(Default::default());
+    let mut all_arg_names = FxHashSet::with_capacity_and_hasher(all_args.len(), Default::default());
     for arg in all_args {
         let arg_name = &arg.arg;
         // Check for duplicate arguments in the function definition.
-        if !all_arg_names.insert(arg_name) {
+        if !all_arg_names.insert(arg_name.as_str()) {
             return Err(LexicalError {
                 error: LexicalErrorType::DuplicateArgumentError(arg_name.to_string()),
                 location: arg.start(),
@@ -104,16 +110,14 @@ pub(crate) fn parse_args(func_args: Vec<FunctionArgument>) -> Result<ArgumentLis
             Some((start, end, name)) => {
                 // Check for duplicate keyword arguments in the call.
                 if let Some(keyword_name) = &name {
-                    if keyword_names.contains(keyword_name) {
+                    if !keyword_names.insert(keyword_name.to_string()) {
                         return Err(LexicalError {
                             error: LexicalErrorType::DuplicateKeywordArgumentError(
                                 keyword_name.to_string(),
                             ),
                             location: start,
                         });
                     }
-
-                    keyword_names.insert(keyword_name.clone());
                 } else {
                     double_starred = true;
                 }