From a2389eeaa85a79ff8c58525df912ff1aafb16e9f Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 19 Jun 2022 19:05:44 -0700
Subject: [PATCH] Call 'format!' through an unambiguous path

Repro:

    use quote::format_ident;

    macro_rules! format {
        () => {};
    }

    fn main() {
        let _ = format_ident!("foo");
    }

Previously:

    error: no rules expected the token `"foo"`
     --> src/main.rs:8:13
      |
    3 | macro_rules! format {
      | ------------------- when calling this macro
    ...
    8 |     let _ = format_ident!("foo");
      |             ^^^^^^^^^^^^^^^^^^^^ no rules expected this token in macro call
      |
      = note: this error originates in the macro `format_ident` (in Nightly builds, run with -Z macro-backtrace for more info)
---
 src/format.rs  | 5 ++++-
 src/runtime.rs | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/format.rs b/src/format.rs
index 5e44b01..f7b1e03 100644
--- a/src/format.rs
+++ b/src/format.rs
@@ -129,7 +129,10 @@ macro_rules! format_ident {
 macro_rules! format_ident_impl {
     // Final state
     ([$span:expr, $($fmt:tt)*]) => {
-        $crate::__private::mk_ident(&format!($($fmt)*), $span)
+        $crate::__private::mk_ident(
+            &$crate::__private::format!($($fmt)*),
+            $span,
+        )
     };
 
     // Span argument
diff --git a/src/runtime.rs b/src/runtime.rs
index 14dd3ba..b6950ba 100644
--- a/src/runtime.rs
+++ b/src/runtime.rs
@@ -4,6 +4,7 @@ use std::iter;
 use std::ops::BitOr;
 
 pub use proc_macro2::*;
+pub use std::format;
 
 pub struct HasIterator; // True
 pub struct ThereIsNoIteratorInRepetition; // False