diff --git a/crates/typst-syntax/src/lexer.rs b/crates/typst-syntax/src/lexer.rs
index 5d684139f..8875d171c 100644
--- a/crates/typst-syntax/src/lexer.rs
+++ b/crates/typst-syntax/src/lexer.rs
@@ -862,11 +862,11 @@ impl Lexer<'_> {
                 "number literals may not start or end with an underscore"
             ));
         }
-        let number = ignore_underscores(number);
+        let number2 = ignore_underscores(number);
 
-        let kind = if i64::from_str_radix(&number, base).is_ok() {
+        let kind = if i64::from_str_radix(&number2, base).is_ok() {
             SyntaxKind::Int
-        } else if base == 10 && number.parse::<f64>().is_ok() {
+        } else if base == 10 && number2.parse::<f64>().is_ok() {
             SyntaxKind::Float
         } else {
             return self.error(match base {
diff --git a/tests/suite/foundations/int.typ b/tests/suite/foundations/int.typ
index ace65939b..9175da03b 100644
--- a/tests/suite/foundations/int.typ
+++ b/tests/suite/foundations/int.typ
@@ -7,10 +7,14 @@
 --- int-base-binary-invalid ---
 // Error: 2-7 invalid binary number: 0b123
 #0b123
+// Error: 2-8 invalid binary number: 0b1_23
+#0b1_23
 
 --- int-base-hex-invalid ---
 // Error: 2-8 invalid hexadecimal number: 0x123z
 #0x123z
+// Error: 2-9 invalid hexadecimal number: 0x12_3z
+#0x12_3z
 
 --- int-constructor ---
 // Test conversion to numbers.