From e04304ffa3faad9677f313a199020c1f78f74fa0 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 19 Jun 2022 18:03:46 -0700
Subject: [PATCH 1/2] Move raw ident validate into validate_ident

---
 src/fallback.rs | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/src/fallback.rs b/src/fallback.rs
index 80e5cced..8567a13b 100644
--- a/src/fallback.rs
+++ b/src/fallback.rs
@@ -638,11 +638,7 @@ pub(crate) struct Ident {
 
 impl Ident {
     fn _new(string: &str, raw: bool, span: Span) -> Self {
-        validate_ident(string);
-
-        if raw && !Self::can_be_raw(string) {
-            panic!("`{}` cannot be a raw identifier", string);
-        }
+        validate_ident(string, raw);
 
         Ident {
             sym: string.to_owned(),
@@ -651,13 +647,6 @@ impl Ident {
         }
     }
 
-    fn can_be_raw(string: &str) -> bool {
-        match string {
-            "" | "_" | "super" | "self" | "Self" | "crate" | "$crate" | "{{root}}" => false,
-            _ => true,
-        }
-    }
-
     pub fn new(string: &str, span: Span) -> Self {
         Ident::_new(string, false, span)
     }
@@ -683,7 +672,7 @@ pub(crate) fn is_ident_continue(c: char) -> bool {
     unicode_ident::is_xid_continue(c)
 }
 
-fn validate_ident(string: &str) {
+fn validate_ident(string: &str, raw: bool) {
     let validate = string;
     if validate.is_empty() {
         panic!("Ident is not allowed to be empty; use Option<Ident>");
@@ -710,6 +699,12 @@ fn validate_ident(string: &str) {
     if !ident_ok(validate) {
         panic!("{:?} is not a valid Ident", string);
     }
+
+    if raw {
+        if let "" | "_" | "super" | "self" | "Self" | "crate" | "$crate" | "{{root}}" = string {
+            panic!("`{}` cannot be a raw identifier", string);
+        }
+    }
 }
 
 impl PartialEq for Ident {

From 868a8ea2d94a705e709dc77a6803cee05ed3d5e4 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 19 Jun 2022 18:08:19 -0700
Subject: [PATCH 2/2] Restore compatibility with rustc older than 1.33

    error[E0658]: multiple patterns in `if let` and `while let` are unstable (see issue #48215)
       --> src/fallback.rs:704:9
        |
    704 | /         if let "" | "_" | "super" | "self" | "Self" | "crate" | "$crate" | "{{root}}" = string {
    705 | |             panic!("`{}` cannot be a raw identifier", string);
    706 | |         }
        | |_________^
---
 src/fallback.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/fallback.rs b/src/fallback.rs
index 8567a13b..fecc9b3e 100644
--- a/src/fallback.rs
+++ b/src/fallback.rs
@@ -701,8 +701,11 @@ fn validate_ident(string: &str, raw: bool) {
     }
 
     if raw {
-        if let "" | "_" | "super" | "self" | "Self" | "crate" | "$crate" | "{{root}}" = string {
-            panic!("`{}` cannot be a raw identifier", string);
+        match string {
+            "" | "_" | "super" | "self" | "Self" | "crate" | "$crate" | "{{root}}" => {
+                panic!("`{}` cannot be a raw identifier", string);
+            }
+            _ => {}
         }
     }
 }