diff --git a/src/packages/arithmetic.rs b/src/packages/arithmetic.rs
index 7b011ceb..c848fbe3 100644
--- a/src/packages/arithmetic.rs
+++ b/src/packages/arithmetic.rs
@@ -16,8 +16,8 @@ use num_traits::float::Float;
 use crate::stdlib::{format, string::String};
 
 #[inline(always)]
-pub fn make_err(msg: String) -> Box<EvalAltResult> {
-    EvalAltResult::ErrorArithmetic(msg, Position::none()).into()
+pub fn make_err(msg: impl Into<String>) -> Box<EvalAltResult> {
+    EvalAltResult::ErrorArithmetic(msg.into(), Position::none()).into()
 }
 
 macro_rules! gen_arithmetic_functions {
diff --git a/src/packages/time_basic.rs b/src/packages/time_basic.rs
index f53e703c..ab0cbd5e 100644
--- a/src/packages/time_basic.rs
+++ b/src/packages/time_basic.rs
@@ -34,7 +34,11 @@ mod time_functions {
     pub fn elapsed(timestamp: &mut Instant) -> Result<Dynamic, Box<EvalAltResult>> {
         #[cfg(not(feature = "no_float"))]
         {
-            Ok((timestamp.elapsed().as_secs_f64() as FLOAT).into())
+            if *timestamp <= Instant::now() {
+                Ok((timestamp.elapsed().as_secs_f64() as FLOAT).into())
+            } else {
+                Err(make_arithmetic_err("Time-stamp is later than now"))
+            }
         }
 
         #[cfg(feature = "no_float")]
@@ -46,6 +50,8 @@ mod time_functions {
                     "Integer overflow for timestamp.elapsed: {}",
                     seconds
                 )))
+            } else if *timestamp <= Instant::now() {
+                Err(make_arithmetic_err("Time-stamp is later than now"))
             } else {
                 Ok((seconds as INT).into())
             }