// $ cargo bench --features full --bench file

#![feature(rustc_private, test)]
#![recursion_limit = "1024"]
#![allow(
    clippy::items_after_statements,
    clippy::missing_panics_doc,
    clippy::must_use_candidate
)]

extern crate test;

#[macro_use]
#[path = "../tests/macros/mod.rs"]
mod macros;

#[path = "../tests/common/mod.rs"]
mod common;
#[path = "../tests/repo/mod.rs"]
pub mod repo;

use proc_macro2::{Span, TokenStream};
use std::fs;
use std::str::FromStr;
use syn::parse::{ParseStream, Parser};
use test::Bencher;

const FILE: &str = "tests/rust/library/core/src/str/mod.rs";

fn get_tokens() -> TokenStream {
    repo::clone_rust();
    let content = fs::read_to_string(FILE).unwrap();
    TokenStream::from_str(&content).unwrap()
}

#[bench]
fn baseline(b: &mut Bencher) {
    let tokens = get_tokens();
    b.iter(|| drop(tokens.clone()));
}

#[bench]
fn create_token_buffer(b: &mut Bencher) {
    let tokens = get_tokens();
    fn immediate_fail(_input: ParseStream) -> syn::Result<()> {
        Err(syn::Error::new(Span::call_site(), ""))
    }
    b.iter(|| immediate_fail.parse2(tokens.clone()));
}

#[bench]
fn parse_file(b: &mut Bencher) {
    let tokens = get_tokens();
    b.iter(|| syn::parse2::<syn::File>(tokens.clone()));
}

// $ cargo bench --features full --bench file

#![feature(rustc_private, test)]
#![recursion_limit = "1024"]
#![allow(clippy::missing_panics_doc, clippy::must_use_candidate)]

extern crate test;

#[macro_use]
#[path = "../tests/macros/mod.rs"]
mod macros;

#[path = "../tests/common/mod.rs"]
mod common;
#[path = "../tests/repo/mod.rs"]
pub mod repo;

use proc_macro2::TokenStream;
use std::fs;
use std::str::FromStr;
use test::Bencher;

const FILE: &str = "tests/rust/library/core/src/str/mod.rs";

fn get_tokens() -> TokenStream {
    repo::clone_rust();
    let content = fs::read_to_string(FILE).unwrap();
    TokenStream::from_str(&content).unwrap()
}

#[bench]
fn baseline(b: &mut Bencher) {
    let tokens = get_tokens();
    b.iter(|| drop(tokens.clone()));
}

#[bench]
fn parse_file(b: &mut Bencher) {
    let tokens = get_tokens();
    b.iter(|| syn::parse2::<syn::File>(tokens.clone()));
}

--- 
+++ 
@@ -2,7 +2,11 @@
 
 #![feature(rustc_private, test)]
 #![recursion_limit = "1024"]
-#![allow(clippy::missing_panics_doc, clippy::must_use_candidate)]
+#![allow(
+    clippy::items_after_statements,
+    clippy::missing_panics_doc,
+    clippy::must_use_candidate
+)]
 
 extern crate test;
 
@@ -15,9 +19,10 @@
 #[path = "../tests/repo/mod.rs"]
 pub mod repo;
 
-use proc_macro2::TokenStream;
+use proc_macro2::{Span, TokenStream};
 use std::fs;
 use std::str::FromStr;
+use syn::parse::{ParseStream, Parser};
 use test::Bencher;
 
 const FILE: &str = "tests/rust/library/core/src/str/mod.rs";
@@ -35,6 +40,15 @@
 }
 
 #[bench]
+fn create_token_buffer(b: &mut Bencher) {
+    let tokens = get_tokens();
+    fn immediate_fail(_input: ParseStream) -> syn::Result<()> {
+        Err(syn::Error::new(Span::call_site(), ""))
+    }
+    b.iter(|| immediate_fail.parse2(tokens.clone()));
+}
+
+#[bench]
 fn parse_file(b: &mut Bencher) {
     let tokens = get_tokens();
     b.iter(|| syn::parse2::<syn::File>(tokens.clone()));
Add a benchmark of TokenBuffer::inner_new
