Fix sleep bug.

CHANGELOG.md

@@ -37,6 +37,7 @@ Fixes to bugs found via fuzzing
 * Fixed improper parsing of numbers with too many decimal points.
 * Fixed exponential running time when raising a decimal number to a very large power (> 1 million) -- it now returns an overflow error.
 * Shared values that contain reference loops no longer cause a stack overflow when printing.
+* `sleep` no longer panics on `NaN`.
 
 Other bug fixes
 ---------------

src/packages/lang_core.rs

@@ -136,7 +136,7 @@ mod core_functions {
     #[cfg(not(feature = "no_std"))]
     #[rhai_fn(name = "sleep", volatile)]
     pub fn sleep_float(seconds: FLOAT) {
-        if seconds <= 0.0 {
+        if !seconds.is_normal() || seconds.is_sign_negative() {
             return;
         }