diff --git a/compiler/can/src/num.rs b/compiler/can/src/num.rs
index ba84bd4760..4bb5f8088d 100644
--- a/compiler/can/src/num.rs
+++ b/compiler/can/src/num.rs
@@ -80,7 +80,17 @@ pub fn float_expr_from_result(
 pub fn finish_parsing_int(raw: &str, is_negative: bool) -> Result<i64, (&str, IntErrorKind)> {
     // Ignore underscores.
     let radix = 10;
-    from_str_radix::<i64>(raw.replace("_", "").as_str(), radix).map_err(|e| (raw, e.kind))
+    let number =
+        from_str_radix::<i64>(raw.replace("_", "").as_str(), radix).map_err(|e| (raw, e.kind))?;
+
+    if is_negative {
+        match number.checked_neg() {
+            None => Err((raw, IntErrorKind::Overflow)),
+            Some(value) => Ok(value),
+        }
+    } else {
+        Ok(number)
+    }
 }
 
 #[inline(always)]
@@ -108,7 +118,11 @@ pub fn finish_parsing_base(
 #[inline(always)]
 pub fn finish_parsing_float(raw: &str, is_negative: bool) -> Result<f64, (&str, FloatErrorKind)> {
     // Ignore underscores.
-    match raw.replace("_", "").parse::<f64>() {
+    match raw
+        .replace("_", "")
+        .parse::<f64>()
+        .map(|x| if is_negative { -x } else { x })
+    {
         Ok(float) if float.is_finite() => Ok(float),
         Ok(float) => {
             if float.is_sign_positive() {