diff --git a/Cargo.lock b/Cargo.lock
index 673e609fa6f4..bd950310b737 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5409,9 +5409,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.1"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+checksum = "8ccb82d61f80a663efe1f787a51b16b5a51e3314d6ac365b08639f52387b33f3"
 
 [[package]]
 name = "unicode_categories"
diff --git a/compiler/rustc_lexer/src/lib.rs b/compiler/rustc_lexer/src/lib.rs
index 4cb2a6ca50f8..b5e6d256a996 100644
--- a/compiler/rustc_lexer/src/lib.rs
+++ b/compiler/rustc_lexer/src/lib.rs
@@ -273,24 +273,14 @@ pub fn is_whitespace(c: char) -> bool {
 /// a formal definition of valid identifier name.
 pub fn is_id_start(c: char) -> bool {
     // This is XID_Start OR '_' (which formally is not a XID_Start).
-    // We also add fast-path for ascii idents
-    ('a'..='z').contains(&c)
-        || ('A'..='Z').contains(&c)
-        || c == '_'
-        || (c > '\x7f' && unicode_xid::UnicodeXID::is_xid_start(c))
+    c == '_' || unicode_xid::UnicodeXID::is_xid_start(c)
 }
 
 /// True if `c` is valid as a non-first character of an identifier.
 /// See [Rust language reference](https://doc.rust-lang.org/reference/identifiers.html) for
 /// a formal definition of valid identifier name.
 pub fn is_id_continue(c: char) -> bool {
-    // This is exactly XID_Continue.
-    // We also add fast-path for ascii idents
-    ('a'..='z').contains(&c)
-        || ('A'..='Z').contains(&c)
-        || ('0'..='9').contains(&c)
-        || c == '_'
-        || (c > '\x7f' && unicode_xid::UnicodeXID::is_xid_continue(c))
+    unicode_xid::UnicodeXID::is_xid_continue(c)
 }
 
 /// The passed string is lexically an identifier.