From cf97f6d1adbd00ae3527e1b3ed18d1b40c084f6c Mon Sep 17 00:00:00 2001
From: overlookmotel <557937+overlookmotel@users.noreply.github.com>
Date: Mon, 16 Sep 2024 04:10:30 +0000
Subject: [PATCH] refactor(ast): import `syn` types in `ast` macro (#5792)

Pure refactor. Import `syn` types with a use statement. This allows shortening the rest of the code, which, in my opinion, makes it easier to read.
---
 crates/oxc_ast_macros/src/ast.rs | 27 ++++++++++++---------------
 crates/oxc_ast_macros/src/lib.rs |  3 ++-
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/crates/oxc_ast_macros/src/ast.rs b/crates/oxc_ast_macros/src/ast.rs
index 6e8aea1f9c764..5207d67b3300a 100644
--- a/crates/oxc_ast_macros/src/ast.rs
+++ b/crates/oxc_ast_macros/src/ast.rs
@@ -1,12 +1,11 @@
 use proc_macro2::TokenStream;
 use quote::quote;
+use syn::{punctuated::Punctuated, token::Comma, Attribute, Fields, Ident, Item, ItemEnum};
 
-pub fn ast(input: &syn::Item) -> TokenStream {
+pub fn ast(input: &Item) -> TokenStream {
     let (head, tail) = match input {
-        syn::Item::Enum(enum_) => (enum_repr(enum_), assert_generated_derives(&enum_.attrs)),
-        syn::Item::Struct(struct_) => {
-            (quote!(#[repr(C)]), assert_generated_derives(&struct_.attrs))
-        }
+        Item::Enum(enum_) => (enum_repr(enum_), assert_generated_derives(&enum_.attrs)),
+        Item::Struct(struct_) => (quote!(#[repr(C)]), assert_generated_derives(&struct_.attrs)),
         _ => unreachable!(),
     };
 
@@ -19,8 +18,8 @@ pub fn ast(input: &syn::Item) -> TokenStream {
 }
 
 /// If `enum_` has any non-unit variant, returns `#[repr(C, u8)]`, otherwise returns `#[repr(u8)]`.
-fn enum_repr(enum_: &syn::ItemEnum) -> TokenStream {
-    if enum_.variants.iter().any(|var| !matches!(var.fields, syn::Fields::Unit)) {
+fn enum_repr(enum_: &ItemEnum) -> TokenStream {
+    if enum_.variants.iter().any(|var| !matches!(var.fields, Fields::Unit)) {
         quote!(#[repr(C, u8)])
     } else {
         quote!(#[repr(u8)])
@@ -42,23 +41,21 @@ fn enum_repr(enum_: &syn::ItemEnum) -> TokenStream {
 ///
 /// If `GetSpan` is not in scope, or it is not the correct `oxc_span::GetSpan`,
 /// this will raise a compilation error.
-fn assert_generated_derives(attrs: &[syn::Attribute]) -> TokenStream {
+fn assert_generated_derives(attrs: &[Attribute]) -> TokenStream {
     #[inline]
-    fn parse(attr: &syn::Attribute) -> impl Iterator<Item = syn::Ident> {
-        attr.parse_args_with(
-            syn::punctuated::Punctuated::<syn::Ident, syn::token::Comma>::parse_terminated,
-        )
-        .expect("`generate_derive` only accepts traits as single segment paths, Found an invalid argument")
+    fn parse(attr: &Attribute) -> impl Iterator<Item = Ident> {
+        attr.parse_args_with(Punctuated::<Ident, Comma>::parse_terminated)
+        .expect("`#[generate_derive]` only accepts traits as single segment paths. Found an invalid argument.")
         .into_iter()
     }
 
     // TODO: benchmark this to see if a lazy static cell containing `HashMap` would perform better.
     #[inline]
     fn abs_trait(
-        ident: &syn::Ident,
+        ident: &Ident,
     ) -> (/* absolute type path */ TokenStream, /* possible generics */ TokenStream) {
         #[cold]
-        fn invalid_derive(ident: &syn::Ident) -> ! {
+        fn invalid_derive(ident: &Ident) -> ! {
             panic!(
                 "Invalid derive trait(generate_derive): {ident}.\n\
                     Help: If you are trying to implement a new `generate_derive` trait, \
diff --git a/crates/oxc_ast_macros/src/lib.rs b/crates/oxc_ast_macros/src/lib.rs
index d8c0efce8f9a0..f657bff3281d2 100644
--- a/crates/oxc_ast_macros/src/lib.rs
+++ b/crates/oxc_ast_macros/src/lib.rs
@@ -1,4 +1,5 @@
 use proc_macro::TokenStream;
+use syn::{parse_macro_input, Item};
 
 mod ast;
 
@@ -69,7 +70,7 @@ mod ast;
 /// 2. `tsify`
 #[proc_macro_attribute]
 pub fn ast(_args: TokenStream, input: TokenStream) -> TokenStream {
-    let input = syn::parse_macro_input!(input as syn::Item);
+    let input = parse_macro_input!(input as Item);
     let expanded = ast::ast(&input);
     TokenStream::from(expanded)
 }