An error is returned when the number fails to parse. #704

parser/src/parse/mod.rs

@@ -150,7 +150,11 @@ fn parse_number(pair: Pair<Rule>, pc: &mut PositionCalculator) -> Result<Positio
     debug_assert_eq!(pair.as_rule(), Rule::number);
     let pos = pc.step(&pair);
     Ok(Positioned::new(
-        pair.as_str().parse().expect("failed to parse number"),
+        pair.as_str().parse().map_err(|err| Error::Syntax {
+            message: format!("invalid number: {}", err),
+            start: pos,
+            end: None,
+        })?,
         pos,
     ))
 }