Fix all features.

src/any.rs

@@ -212,9 +212,11 @@ pub(crate) fn map_std_type_name(name: &str) -> &str {
         "string"
     } else if name == type_name::<FnPtr>() {
         "Fn"
-    } else if name == type_name::<Instant>() {
-        "timestamp"
     } else {
+        #[cfg(not(feature = "no_std"))]
+        if name == type_name::<Instant>() {
+            return "timestamp";
+        }
         #[cfg(not(feature = "no_index"))]
         if name == type_name::<Array>() {
             return "array";

src/engine.rs

@@ -26,7 +26,7 @@ use crate::stdlib::{
     boxed::Box,
     collections::{HashMap, HashSet},
     convert::TryFrom,
-    format,
+    fmt, format,
     iter::{empty, once},
     mem,
     string::{String, ToString},
@@ -96,6 +96,7 @@ pub const MARKER_BLOCK: &str = "$block$";
 pub const MARKER_IDENT: &str = "$ident$";
 
 #[cfg(feature = "internals")]
+#[derive(Debug, Clone)]
 pub struct Expression<'a>(&'a Expr);
 
 #[cfg(feature = "internals")]
@@ -346,6 +347,15 @@ pub struct Engine {
     pub(crate) max_map_size: usize,
 }
 
+impl fmt::Debug for Engine {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.id.as_ref() {
+            Some(id) => write!(f, "Engine({})", id),
+            None => f.write_str("Engine"),
+        }
+    }
+}
+
 impl Default for Engine {
     fn default() -> Self {
         // Create the new scripting Engine
@@ -1095,6 +1105,7 @@ impl Engine {
             let mut hash = *hash;
 
             // Check if it is a map method call in OOP style
+            #[cfg(not(feature = "no_object"))]
             if let Some(map) = obj.downcast_ref::<Map>() {
                 if let Some(val) = map.get(fn_name) {
                     if let Some(f) = val.downcast_ref::<FnPtr>() {

src/fn_native.rs

@@ -7,7 +7,7 @@ use crate::result::EvalAltResult;
 use crate::token::{is_valid_identifier, Position};
 use crate::utils::ImmutableString;
 
-use crate::stdlib::{boxed::Box, convert::TryFrom, fmt, rc::Rc, sync::Arc};
+use crate::stdlib::{boxed::Box, convert::TryFrom, fmt, rc::Rc, string::String, sync::Arc};
 
 /// Trait that maps to `Send + Sync` only under the `sync` feature.
 #[cfg(feature = "sync")]
@@ -86,7 +86,7 @@ impl TryFrom<ImmutableString> for FnPtr {
             Ok(Self(value))
         } else {
             Err(Box::new(EvalAltResult::ErrorFunctionNotFound(
-                value.to_string(),
+                value.into(),
                 Position::none(),
             )))
         }

src/fn_register.rs

@@ -10,7 +10,12 @@ use crate::r#unsafe::unsafe_cast_box;
 use crate::result::EvalAltResult;
 use crate::utils::ImmutableString;
 
-use crate::stdlib::{any::TypeId, boxed::Box, mem};
+use crate::stdlib::{
+    any::TypeId,
+    boxed::Box,
+    mem,
+    string::{String, ToString},
+};
 
 /// Trait to register custom functions with the `Engine`.
 pub trait RegisterFn<FN, ARGS, RET> {

src/module.rs

@@ -25,11 +25,13 @@ use crate::stdlib::{
     num::NonZeroUsize,
     ops::{Deref, DerefMut},
     string::{String, ToString},
-    sync::RwLock,
     vec,
     vec::Vec,
 };
 
+#[cfg(not(feature = "no_std"))]
+use crate::stdlib::sync::RwLock;
+
 /// Return type of module-level Rust function.
 pub type FuncReturn<T> = Result<T, Box<EvalAltResult>>;
 

src/packages/mod.rs

@@ -52,7 +52,7 @@ pub type PackageLibrary = Shared<Module>;
 
 /// Type containing a collection of `PackageLibrary` instances.
 /// All function and type iterator keys in the loaded packages are indexed for fast access.
-#[derive(Clone, Default)]
+#[derive(Debug, Clone, Default)]
 pub(crate) struct PackagesCollection(StaticVec<PackageLibrary>);
 
 impl PackagesCollection {

src/settings.rs

@@ -4,6 +4,8 @@ use crate::optimize::OptimizationLevel;
 use crate::packages::PackageLibrary;
 use crate::token::is_valid_identifier;
 
+use crate::stdlib::{boxed::Box, format, string::String};
+
 impl Engine {
     /// Load a new package into the `Engine`.
     ///

src/stdlib.rs

@@ -16,7 +16,7 @@ mod inner {
     pub use core_error as error;
 
     pub mod collections {
-        pub use hashbrown::HashMap;
+        pub use hashbrown::{HashMap, HashSet};
     }
 }
 

src/syntax.rs

@@ -75,7 +75,7 @@ impl Engine {
             ) -> Result<Dynamic, Box<EvalAltResult>>
             + SendSync
             + 'static,
-    ) -> Result<self, Box<LexError>> {
+    ) -> Result<&mut Self, Box<LexError>> {
         if value.is_empty() {
             return Err(Box::new(LexError::ImproperSymbol("".to_string())));
         }

src/token.rs

@@ -13,7 +13,7 @@ use crate::stdlib::{
     boxed::Box,
     char,
     collections::HashMap,
-    fmt,
+    fmt, format,
     iter::Peekable,
     str::{Chars, FromStr},
     string::{String, ToString},