Use smallvec/union for nightly builds.

Cargo.toml

@@ -38,7 +38,7 @@ internals = []      # expose internal data structures
 unicode-xid-ident = ["unicode-xid"]  # allow Unicode Standard Annex #31 for identifiers.
 
 # compiling for no-std
-no_std = [ "no_closure", "num-traits/libm", "hashbrown", "core-error", "libm", "ahash" ]
+no_std = [ "smallvec/union", "num-traits/libm", "hashbrown", "core-error", "libm", "ahash" ]
 
 [profile.release]
 lto = "fat"

tests/functions.rs

@@ -1,6 +1,5 @@
 #![cfg(not(feature = "no_function"))]
 use rhai::{Engine, EvalAltResult, ParseErrorType, INT};
-use std::io::Read;
 
 #[test]
 fn test_functions() -> Result<(), Box<EvalAltResult>> {