diff --git a/core/rustfmt.toml b/core/rustfmt.toml
new file mode 100644
index 000000000000..f5457b6a24fa
--- /dev/null
+++ b/core/rustfmt.toml
@@ -0,0 +1 @@
+single_line_if_else_max_width = 49
diff --git a/core/src/avm1/globals/number.rs b/core/src/avm1/globals/number.rs
index 28eb19eed8f0..0155ae5f1baa 100644
--- a/core/src/avm1/globals/number.rs
+++ b/core/src/avm1/globals/number.rs
@@ -85,7 +85,11 @@ fn to_string<'gc>(
         [] => 10,
         [radix, ..] => {
             let radix = radix.coerce_to_f64(activation)? as i32;
-            if (2..=36).contains(&radix) { radix } else { 10 }
+            if (2..=36).contains(&radix) {
+                radix
+            } else {
+                10
+            }
         }
     };