Merge pull request #673 from schungx/master

Fix serde for byte arrays.

CHANGELOG.md

@@ -1,10 +1,31 @@
 Rhai Release Notes
 ==================
 
+Version 1.12.0
+==============
+
+Net features
+------------
+
+### `Engine::call_fn_with_options`
+
+* `Engine::call_fn_raw` is deprecated in favor of `Engine::call_fn_with_options` which allows setting options for the function call.
+* The options are for future-proofing the API.
+* In this version, it gains the ability to set the value of the _custom state_ (accessible via `NativeCallContext::tag`) for a function evaluation, overriding `Engine::set_default_tag`.
+
+Enhancements
+------------
+
+* `CallableFunction` is exported under `internals`.
+* The `TypeBuilder` type and `CustomType` trait are no longer marked as volatile.
+* `FuncArgs` is also implemented for arrays.
+* `Engine::set_XXX` API can now be chained.
+
+
 Version 1.11.0
 ==============
 
-Speed Improvements
+Speed improvements
 ------------------
 
 * Due to a code refactor, built-in operators for standard types now run even faster, in certain cases by 20-30%.

Cargo.toml

@@ -3,7 +3,7 @@ members = [".", "codegen"]
 
 [package]
 name = "rhai"
-version = "1.11.0"
+version = "1.12.0"
 rust-version = "1.61.0"
 edition = "2018"
 resolver = "2"
@@ -37,7 +37,7 @@ getrandom = { version = "0.2", optional = true }
 rustyline = { version = "10", optional = true }
 
 [dev-dependencies]
-serde_bytes = "0.11"
+rmp-serde = "1.1"
 serde_json = { version = "1.0", default-features = false, features = ["alloc"] }
 
 [features]

README.md

@@ -33,7 +33,7 @@ Standard features
 -----------------
 
 * Simple language similar to JavaScript+Rust with [dynamic](https://rhai.rs/book/language/dynamic.html) typing.
-* Fairly efficient evaluation (1 million iterations in 0.3 sec on a single-core, 2.3 GHz Linux VM).
+* Fairly efficient evaluation (1 million iterations in 0.23 sec on a single-core, 2.3 GHz Linux VM).
 * Tight integration with native Rust [functions](https://rhai.rs/book/rust/functions.html) and [types](https://rhai.rs/book/rust/custom-types.html), including [getters/setters](https://rhai.rs/book/rust/getters-setters.html), [methods](https://rhai.rs/book/rust/methods.html) and [indexers](https://rhai.rs/book/rust/indexers.html).
 * Freely pass Rust values into a script as [variables](https://rhai.rs/book/language/variables.html)/[constants](https://rhai.rs/book/language/constants.html) via an external [`Scope`](https://rhai.rs/book/engine/scope.html) - all clonable Rust types are supported; no need to implement any special trait. Or tap directly into the [variable resolution process](https://rhai.rs/book/engine/var.html).
 * Built-in support for most common [data types](https://rhai.rs/book/language/values-and-types.html) including booleans, [integers](https://rhai.rs/book/language/numbers.html), [floating-point numbers](https://rhai.rs/book/language/numbers.html) (including [`Decimal`](https://crates.io/crates/rust_decimal)), [strings](https://rhai.rs/book/language/strings-chars.html), [Unicode characters](https://rhai.rs/book/language/strings-chars.html), [arrays](https://rhai.rs/book/language/arrays.html) (including packed [byte arrays](https://rhai.rs/book/language/blobs.html)) and [object maps](https://rhai.rs/book/language/object-maps.html).

examples/event_handler_js/main.rs

@@ -8,7 +8,7 @@ pub fn main() {
 #[cfg(not(feature = "no_function"))]
 #[cfg(not(feature = "no_object"))]
 pub fn main() {
-    use rhai::{Dynamic, Engine, Map, Scope, AST};
+    use rhai::{CallFnOptions, Dynamic, Engine, ImmutableString, Map, Scope, AST};
     use std::io::{stdin, stdout, Write};
 
     const SCRIPT_FILE: &str = "event_handler_js/script.rhai";
@@ -98,7 +98,12 @@ pub fn main() {
     println!();
 
     // Run the 'init' function to initialize the state, retaining variables.
-    let result = engine.call_fn_raw(&mut scope, &ast, false, true, "init", Some(&mut states), []);
+
+    let options = CallFnOptions::new()
+        .eval_ast(false)
+        .bind_this_ptr(&mut states);
+
+    let result = engine.call_fn_with_options::<()>(options, &mut scope, &ast, "init", ());
 
     if let Err(err) = result {
         eprintln!("! {err}")
@@ -124,7 +129,7 @@ pub fn main() {
         let mut fields = input.trim().splitn(2, ' ');
 
         let event = fields.next().expect("event").trim();
-        let arg = fields.next().unwrap_or("");
+        let arg = fields.next().unwrap_or("").to_string();
 
         // Process event
         match event {
@@ -146,10 +151,11 @@ pub fn main() {
                 let engine = &handler.engine;
                 let scope = &mut handler.scope;
                 let ast = &handler.ast;
-                let this_ptr = Some(&mut handler.states);
+                let options = CallFnOptions::new()
+                    .eval_ast(false)
+                    .bind_this_ptr(&mut handler.states);
 
-                let result =
+                let result = engine.call_fn_with_options::<()>(options, scope, ast, event, (arg,));
-                    engine.call_fn_raw(scope, ast, false, true, event, this_ptr, [arg.into()]);
 
                 if let Err(err) = result {
                     eprintln!("! {err}")

examples/event_handler_main/main.rs

@@ -7,7 +7,7 @@ pub fn main() {
 
 #[cfg(not(feature = "no_function"))]
 pub fn main() {
-    use rhai::{Dynamic, Engine, Scope, AST};
+    use rhai::{CallFnOptions, Dynamic, Engine, Scope, AST};
     use std::io::{stdin, stdout, Write};
 
     const SCRIPT_FILE: &str = "event_handler_main/script.rhai";
@@ -86,7 +86,9 @@ pub fn main() {
     println!();
 
     // Run the 'init' function to initialize the state, retaining variables.
-    let result = engine.call_fn_raw(&mut scope, &ast, false, false, "init", None, []);
+    let options = CallFnOptions::new().eval_ast(false).rewind_scope(false);
+
+    let result = engine.call_fn_with_options::<()>(options, &mut scope, &ast, "init", ());
 
     if let Err(err) = result {
         eprintln!("! {err}")
@@ -107,7 +109,7 @@ pub fn main() {
         let mut fields = input.trim().splitn(2, ' ');
 
         let event = fields.next().expect("event").trim();
-        let arg = fields.next().unwrap_or("");
+        let arg = fields.next().unwrap_or("").to_string();
 
         // Process event
         match event {
@@ -124,7 +126,7 @@ pub fn main() {
                 let scope = &mut handler.scope;
                 let ast = &handler.ast;
 
-                let result = engine.call_fn::<()>(scope, ast, event, (arg.to_string(),));
+                let result = engine.call_fn::<()>(scope, ast, event, (arg,));
 
                 if let Err(err) = result {
                     eprintln!("! {err}")

examples/event_handler_map/main.rs

@@ -121,7 +121,7 @@ pub fn main() {
         let mut fields = input.trim().splitn(2, ' ');
 
         let event = fields.next().expect("event").trim();
-        let arg = fields.next().unwrap_or("");
+        let arg = fields.next().unwrap_or("").to_string();
 
         // Process event
         match event {
@@ -138,7 +138,7 @@ pub fn main() {
                 let scope = &mut handler.scope;
                 let ast = &handler.ast;
 
-                let result = engine.call_fn::<()>(scope, ast, event, (arg.to_string(),));
+                let result = engine.call_fn::<()>(scope, ast, event, (arg,));
 
                 if let Err(err) = result {
                     eprintln!("! {err}")

src/api/build_type.rs

@@ -1,6 +1,4 @@
 //! Trait to build a custom type for use with [`Engine`].
-#![allow(deprecated)]
-
 use crate::{types::dynamic::Variant, Engine, Identifier, RegisterNativeFunction};
 use std::marker::PhantomData;
 #[cfg(feature = "no_std")]
@@ -12,10 +10,6 @@ use crate::func::register::Mut;
 /// Trait to build the API of a custom type for use with an [`Engine`]
 /// (i.e. register the type and its getters, setters, methods, etc.).
 ///
-/// # WARNING - Volatile Trait
-///
-/// This API is volatile and may change in the future.
-///
 /// # Example
 ///
 /// ```
@@ -66,7 +60,6 @@ use crate::func::register::Mut;
 /// # Ok(())
 /// # }
 /// ```
-#[deprecated = "This trait is NOT deprecated, but it is considered volatile and may change in the future."]
 pub trait CustomType: Variant + Clone {
     /// Builds the custom type for use with the [`Engine`].
     ///
@@ -78,10 +71,6 @@ impl Engine {
     /// Build the API of a custom type for use with the [`Engine`].
     ///
     /// The custom type must implement [`CustomType`].
-    ///
-    /// # WARNING - Unstable API
-    ///
-    /// This API is volatile and may change in the future.
     #[inline]
     pub fn build_type<T: CustomType>(&mut self) -> &mut Self {
         T::build(TypeBuilder::new(self));
@@ -99,11 +88,6 @@ impl Engine {
 ///
 /// To define a pretty-print name, call [`with_name`][`TypeBuilder::with_name`],
 /// to use [`Engine::register_type_with_name`] instead.
-///
-/// # WARNING - Volatile Type
-///
-/// This type is volatile and may change in the future.
-#[deprecated = "This type is NOT deprecated, but it is considered volatile and may change in the future."]
 pub struct TypeBuilder<'a, T: Variant + Clone> {
     engine: &'a mut Engine,
     name: Option<&'static str>,

src/api/call_fn.rs

@@ -8,9 +8,70 @@ use crate::{
     reify, Dynamic, Engine, FuncArgs, Position, RhaiResult, RhaiResultOf, Scope, StaticVec, AST,
     ERR,
 };
-use std::any::{type_name, TypeId};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
+use std::{
+    any::{type_name, TypeId},
+    mem,
+};
+
+/// Options for calling a script-defined function via [`Engine::call_fn_with_options`].
+#[derive(Debug, Hash)]
+#[non_exhaustive]
+pub struct CallFnOptions<'t> {
+    /// A value for binding to the `this` pointer (if any).
+    pub this_ptr: Option<&'t mut Dynamic>,
+    /// The custom state of this evaluation run (if any), overrides [`Engine::default_tag`].
+    pub tag: Option<Dynamic>,
+    /// Evaluate the [`AST`] to load necessary modules before calling the function? Default `true`.
+    pub eval_ast: bool,
+    /// Rewind the [`Scope`] after the function call? Default `true`.
+    pub rewind_scope: bool,
+}
+
+impl Default for CallFnOptions<'_> {
+    #[inline(always)]
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<'a> CallFnOptions<'a> {
+    /// Create a default [`CallFnOptions`].
+    #[inline(always)]
+    pub fn new() -> Self {
+        Self {
+            this_ptr: None,
+            tag: None,
+            eval_ast: true,
+            rewind_scope: true,
+        }
+    }
+    /// Bind to the `this` pointer.
+    #[inline(always)]
+    pub fn bind_this_ptr(mut self, value: &'a mut Dynamic) -> Self {
+        self.this_ptr = Some(value);
+        self
+    }
+    /// Set the custom state of this evaluation run (if any).
+    #[inline(always)]
+    pub fn with_tag(mut self, value: impl Variant + Clone) -> Self {
+        self.tag = Some(Dynamic::from(value));
+        self
+    }
+    /// Set whether to evaluate the [`AST`] to load necessary modules before calling the function.
+    #[inline(always)]
+    pub const fn eval_ast(mut self, value: bool) -> Self {
+        self.eval_ast = value;
+        self
+    }
+    /// Set whether to rewind the [`Scope`] after the function call.
+    #[inline(always)]
+    pub const fn rewind_scope(mut self, value: bool) -> Self {
+        self.rewind_scope = value;
+        self
+    }
+}
 
 impl Engine {
     /// Call a script function defined in an [`AST`] with multiple arguments.
@@ -19,15 +80,12 @@ impl Engine {
     ///
     /// The [`AST`] is evaluated before calling the function.
     /// This allows a script to load the necessary modules.
-    /// This is usually desired. If not, a specialized [`AST`] can be prepared that contains only
+    /// This is usually desired. If not, use [`call_fn_with_options`] instead.
-    /// function definitions without any body script via [`AST::clear_statements`].
     ///
     /// # Example
     ///
     /// ```
     /// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
-    /// # #[cfg(not(feature = "no_function"))]
-    /// # {
     /// use rhai::{Engine, Scope};
     ///
     /// let engine = Engine::new();
@@ -51,30 +109,83 @@ impl Engine {
     ///
     /// let result = engine.call_fn::<i64>(&mut scope, &ast, "bar", () )?;
     /// assert_eq!(result, 21);
-    /// # }
     /// # Ok(())
     /// # }
     /// ```
-    #[inline]
+    #[inline(always)]
     pub fn call_fn<T: Variant + Clone>(
         &self,
         scope: &mut Scope,
         ast: &AST,
         name: impl AsRef<str>,
         args: impl FuncArgs,
+    ) -> RhaiResultOf<T> {
+        self.call_fn_with_options(Default::default(), scope, ast, name, args)
+    }
+    /// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
+    ///
+    /// Options are provided via the [`CallFnOptions`] type.
+    /// This is an advanced API.
+    ///
+    /// Not available under `no_function`.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
+    /// use rhai::{Engine, Scope, Dynamic, CallFnOptions};
+    ///
+    /// let engine = Engine::new();
+    ///
+    /// let ast = engine.compile("
+    ///     fn action(x) { this += x; }         // function using 'this' pointer
+    ///     fn decl(x)   { let hello = x; }     // declaring variables
+    /// ")?;
+    ///
+    /// let mut scope = Scope::new();
+    /// scope.push("foo", 42_i64);
+    ///
+    /// // Binding the 'this' pointer
+    /// let mut value = 1_i64.into();
+    /// let options = CallFnOptions::new().bind_this_ptr(&mut value);
+    ///
+    /// engine.call_fn_with_options(options, &mut scope, &ast, "action", ( 41_i64, ))?;
+    /// assert_eq!(value.as_int().unwrap(), 42);
+    ///
+    /// // Do not rewind scope
+    /// let options = CallFnOptions::default().rewind_scope(false);
+    ///
+    /// engine.call_fn_with_options(options, &mut scope, &ast, "decl", ( 42_i64, ))?;
+    /// assert_eq!(scope.get_value::<i64>("hello").unwrap(), 42);
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[inline(always)]
+    pub fn call_fn_with_options<T: Variant + Clone>(
+        &self,
+        options: CallFnOptions,
+        scope: &mut Scope,
+        ast: &AST,
+        name: impl AsRef<str>,
+        args: impl FuncArgs,
     ) -> RhaiResultOf<T> {
         let mut arg_values = StaticVec::new_const();
         args.parse(&mut arg_values);
 
-        let result = self.call_fn_raw(scope, ast, true, true, name, None, arg_values)?;
+        let result = self._call_fn(
+            options,
+            scope,
+            &mut GlobalRuntimeState::new(self),
+            &mut Caches::new(),
+            ast,
+            name.as_ref(),
+            arg_values.as_mut(),
+        )?;
 
         // Bail out early if the return type needs no cast
         if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
             return Ok(reify!(result => T));
         }
-        if TypeId::of::<T>() == TypeId::of::<()>() {
-            return Ok(reify!(() => T));
-        }
 
         // Cast return type
         let typ = self.map_type_name(result.type_name());
@@ -86,120 +197,6 @@ impl Engine {
     }
     /// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
     ///
-    /// The following options are available:
-    ///
-    /// * whether to evaluate the [`AST`] to load necessary modules before calling the function
-    /// * whether to rewind the [`Scope`] after the function call
-    /// * a value for binding to the `this` pointer (if any)
-    ///
-    /// Not available under `no_function`.
-    ///
-    /// # WARNING - Low Level API
-    ///
-    /// This function is very low level.
-    ///
-    /// # Arguments
-    ///
-    /// All the arguments are _consumed_, meaning that they're replaced by `()`.
-    /// This is to avoid unnecessarily cloning the arguments.
-    ///
-    /// Do not use the arguments after this call. If they are needed afterwards, clone them _before_
-    /// calling this function.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
-    /// # #[cfg(not(feature = "no_function"))]
-    /// # {
-    /// use rhai::{Engine, Scope, Dynamic};
-    ///
-    /// let engine = Engine::new();
-    ///
-    /// let ast = engine.compile("
-    ///     fn add(x, y) { len(x) + y + foo }
-    ///     fn add1(x)   { len(x) + 1 + foo }
-    ///     fn bar()     { foo/2 }
-    ///     fn action(x) { this += x; }         // function using 'this' pointer
-    ///     fn decl(x)   { let hello = x; }     // declaring variables
-    /// ")?;
-    ///
-    /// let mut scope = Scope::new();
-    /// scope.push("foo", 42_i64);
-    ///
-    /// // Call the script-defined function
-    /// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "add", None, [ "abc".into(), 123_i64.into() ])?;
-    /// //                                                                   ^^^^ no 'this' pointer
-    /// assert_eq!(result.cast::<i64>(), 168);
-    ///
-    /// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "add1", None, [ "abc".into() ])?;
-    /// assert_eq!(result.cast::<i64>(), 46);
-    ///
-    /// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "bar", None, [])?;
-    /// assert_eq!(result.cast::<i64>(), 21);
-    ///
-    /// let mut value = 1_i64.into();
-    /// let result = engine.call_fn_raw(&mut scope, &ast, true, true, "action", Some(&mut value), [ 41_i64.into() ])?;
-    /// //                                                                      ^^^^^^^^^^^^^^^^ binding the 'this' pointer
-    /// assert_eq!(value.as_int().unwrap(), 42);
-    ///
-    /// engine.call_fn_raw(&mut scope, &ast, true, false, "decl", None, [ 42_i64.into() ])?;
-    /// //                                         ^^^^^ do not rewind scope
-    /// assert_eq!(scope.get_value::<i64>("hello").unwrap(), 42);
-    /// # }
-    /// # Ok(())
-    /// # }
-    /// ```
-    #[inline(always)]
-    pub fn call_fn_raw(
-        &self,
-        scope: &mut Scope,
-        ast: &AST,
-        eval_ast: bool,
-        rewind_scope: bool,
-        name: impl AsRef<str>,
-        this_ptr: Option<&mut Dynamic>,
-        arg_values: impl AsMut<[Dynamic]>,
-    ) -> RhaiResult {
-        let mut arg_values = arg_values;
-
-        self._call_fn(
-            scope,
-            &mut GlobalRuntimeState::new(self),
-            &mut Caches::new(),
-            ast,
-            eval_ast,
-            rewind_scope,
-            name.as_ref(),
-            this_ptr,
-            arg_values.as_mut(),
-        )
-    }
-    /// _(internals)_ Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
-    /// Exported under the `internals` feature only.
-    ///
-    /// The following options are available:
-    ///
-    /// * whether to evaluate the [`AST`] to load necessary modules before calling the function
-    /// * whether to rewind the [`Scope`] after the function call
-    /// * a value for binding to the `this` pointer (if any)
-    ///
-    /// Not available under `no_function`.
-    ///
-    /// # WARNING - Unstable API
-    ///
-    /// This API is volatile and may change in the future.
-    ///
-    /// # WARNING - Low Level API
-    ///
-    /// This function is _extremely_ low level.
-    ///
-    /// A [`GlobalRuntimeState`] and [`Caches`] need to be passed into the function, which can be
-    /// created via [`GlobalRuntimeState::new`] and [`Caches::new`].
-    ///
-    /// This makes repeatedly calling particular functions more efficient as the functions
-    /// resolution cache is kept intact.
-    ///
     /// # Arguments
     ///
     /// All the arguments are _consumed_, meaning that they're replaced by `()`. This is to avoid
@@ -207,56 +204,31 @@ impl Engine {
     ///
     /// Do not use the arguments after this call. If they are needed afterwards, clone them _before_
     /// calling this function.
-    #[cfg(feature = "internals")]
-    #[deprecated = "This API is NOT deprecated, but it is considered volatile and may change in the future."]
     #[inline(always)]
-    pub fn call_fn_raw_raw(
+    pub(crate) fn _call_fn(
         &self,
+        options: CallFnOptions,
         scope: &mut Scope,
         global: &mut GlobalRuntimeState,
         caches: &mut Caches,
         ast: &AST,
-        eval_ast: bool,
-        rewind_scope: bool,
         name: &str,
-        this_ptr: Option<&mut Dynamic>,
-        arg_values: &mut [Dynamic],
-    ) -> RhaiResult {
-        self._call_fn(
-            scope,
-            global,
-            caches,
-            ast,
-            eval_ast,
-            rewind_scope,
-            name,
-            this_ptr,
-            arg_values,
-        )
-    }
-
-    /// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
-    fn _call_fn(
-        &self,
-        scope: &mut Scope,
-        global: &mut GlobalRuntimeState,
-        caches: &mut Caches,
-        ast: &AST,
-        eval_ast: bool,
-        rewind_scope: bool,
-        name: &str,
-        this_ptr: Option<&mut Dynamic>,
         arg_values: &mut [Dynamic],
     ) -> RhaiResult {
         let statements = ast.statements();
 
         let orig_lib_len = global.lib.len();
 
-        #[cfg(not(feature = "no_function"))]
+        let mut orig_tag = None;
+
+        if let Some(value) = options.tag {
+            orig_tag = Some(mem::replace(&mut global.tag, value));
+        }
+
         global.lib.push(ast.shared_lib().clone());
 
         let mut no_this_ptr = Dynamic::NULL;
-        let this_ptr = this_ptr.unwrap_or(&mut no_this_ptr);
+        let this_ptr = options.this_ptr.unwrap_or(&mut no_this_ptr);
 
         #[cfg(not(feature = "no_module"))]
         let orig_embedded_module_resolver = std::mem::replace(
@@ -264,7 +236,9 @@ impl Engine {
             ast.resolver().cloned(),
         );
 
-        let result = if eval_ast && !statements.is_empty() {
+        let rewind_scope = options.rewind_scope;
+
+        let result = if options.eval_ast && !statements.is_empty() {
             let orig_scope_len = scope.len();
             let scope = &mut *RestoreOnDrop::lock_if(rewind_scope, scope, move |s| {
                 s.rewind(orig_scope_len);
@@ -308,6 +282,11 @@ impl Engine {
         {
             global.embedded_module_resolver = orig_embedded_module_resolver;
         }
+
+        if let Some(value) = orig_tag {
+            global.tag = value;
+        }
+
         global.lib.truncate(orig_lib_len);
 
         result

src/api/deprecated.rs

@@ -117,10 +117,10 @@ impl Engine {
     ///
     /// # Deprecated
     ///
-    /// This method is deprecated. Use [`run_ast_with_scope`][Engine::run_ast_with_scope] instead.
+    /// This method is deprecated. Use [`call_fn_with_options`][Engine::call_fn_with_options] instead.
     ///
     /// This method will be removed in the next major version.
-    #[deprecated(since = "1.1.0", note = "use `call_fn_raw` instead")]
+    #[deprecated(since = "1.1.0", note = "use `call_fn_with_options` instead")]
     #[cfg(not(feature = "no_function"))]
     #[inline(always)]
     pub fn call_fn_dynamic(
@@ -132,8 +132,56 @@ impl Engine {
         this_ptr: Option<&mut Dynamic>,
         arg_values: impl AsMut<[Dynamic]>,
     ) -> RhaiResult {
+        #[allow(deprecated)]
         self.call_fn_raw(scope, ast, eval_ast, true, name, this_ptr, arg_values)
     }
+    /// Call a script function defined in an [`AST`] with multiple [`Dynamic`] arguments.
+    ///
+    /// The following options are available:
+    ///
+    /// * whether to evaluate the [`AST`] to load necessary modules before calling the function
+    /// * whether to rewind the [`Scope`] after the function call
+    /// * a value for binding to the `this` pointer (if any)
+    ///
+    /// Not available under `no_function`.
+    ///
+    /// # Deprecated
+    ///
+    /// This method is deprecated. Use [`call_fn_with_options`][Engine::call_fn_with_options] instead.
+    ///
+    /// This method will be removed in the next major version.
+    #[deprecated(since = "1.12.0", note = "use `call_fn_with_options` instead")]
+    #[cfg(not(feature = "no_function"))]
+    #[inline(always)]
+    pub fn call_fn_raw(
+        &self,
+        scope: &mut Scope,
+        ast: &AST,
+        eval_ast: bool,
+        rewind_scope: bool,
+        name: impl AsRef<str>,
+        this_ptr: Option<&mut Dynamic>,
+        arg_values: impl AsMut<[Dynamic]>,
+    ) -> RhaiResult {
+        let mut arg_values = arg_values;
+
+        let options = crate::CallFnOptions {
+            this_ptr,
+            eval_ast,
+            rewind_scope,
+            ..Default::default()
+        };
+
+        self._call_fn(
+            options,
+            scope,
+            &mut crate::eval::GlobalRuntimeState::new(self),
+            &mut crate::eval::Caches::new(),
+            ast,
+            name.as_ref(),
+            arg_values.as_mut(),
+        )
+    }
     /// Register a custom fallible function with the [`Engine`].
     ///
     /// # Deprecated

src/api/eval.rs

@@ -4,11 +4,14 @@ use crate::eval::{Caches, GlobalRuntimeState};
 use crate::parser::ParseState;
 use crate::types::dynamic::Variant;
 use crate::{
-    Dynamic, Engine, OptimizationLevel, Position, RhaiResult, RhaiResultOf, Scope, AST, ERR,
+    reify, Dynamic, Engine, OptimizationLevel, Position, RhaiResult, RhaiResultOf, Scope, AST, ERR,
 };
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
-use std::{any::type_name, mem};
+use std::{
+    any::{type_name, TypeId},
+    mem,
+};
 
 impl Engine {
     /// Evaluate a string as a script, returning the result value or an error.
@@ -190,6 +193,11 @@ impl Engine {
 
         let result = self.eval_ast_with_scope_raw(global, caches, scope, ast)?;
 
+        // Bail out early if the return type needs no cast
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return Ok(reify!(result => T));
+        }
+
         let typ = self.map_type_name(result.type_name());
 
         result.try_cast::<T>().ok_or_else(|| {

src/api/limits.rs

@@ -102,7 +102,7 @@ impl Default for Limits {
 
 impl Engine {
     /// Is there a data size limit set?
-    #[inline]
+    #[inline(always)]
     pub(crate) const fn has_data_size_limit(&self) -> bool {
         self.limits.max_string_size.is_some()
             || {

src/api/options.rs

@@ -68,8 +68,9 @@ impl Engine {
     }
     /// Set whether `if`-expression is allowed.
     #[inline(always)]
-    pub fn set_allow_if_expression(&mut self, enable: bool) {
+    pub fn set_allow_if_expression(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::IF_EXPR, enable);
+        self
     }
     /// Is `switch` expression allowed?
     /// Default is `true`.
@@ -80,8 +81,9 @@ impl Engine {
     }
     /// Set whether `switch` expression is allowed.
     #[inline(always)]
-    pub fn set_allow_switch_expression(&mut self, enable: bool) {
+    pub fn set_allow_switch_expression(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::SWITCH_EXPR, enable);
+        self
     }
     /// Are loop expressions allowed?
     /// Default is `true`.
@@ -92,8 +94,9 @@ impl Engine {
     }
     /// Set whether loop expressions are allowed.
     #[inline(always)]
-    pub fn set_allow_loop_expressions(&mut self, enable: bool) {
+    pub fn set_allow_loop_expressions(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::LOOP_EXPR, enable);
+        self
     }
     /// Is statement-expression allowed?
     /// Default is `true`.
@@ -104,8 +107,9 @@ impl Engine {
     }
     /// Set whether statement-expression is allowed.
     #[inline(always)]
-    pub fn set_allow_statement_expression(&mut self, enable: bool) {
+    pub fn set_allow_statement_expression(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::STMT_EXPR, enable);
+        self
     }
     /// Is anonymous function allowed?
     /// Default is `true`.
@@ -122,8 +126,9 @@ impl Engine {
     /// Not available under `no_function`.
     #[cfg(not(feature = "no_function"))]
     #[inline(always)]
-    pub fn set_allow_anonymous_fn(&mut self, enable: bool) {
+    pub fn set_allow_anonymous_fn(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::ANON_FN, enable);
+        self
     }
     /// Is looping allowed?
     /// Default is `true`.
@@ -134,8 +139,9 @@ impl Engine {
     }
     /// Set whether looping is allowed.
     #[inline(always)]
-    pub fn set_allow_looping(&mut self, enable: bool) {
+    pub fn set_allow_looping(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::LOOPING, enable);
+        self
     }
     /// Is variables shadowing allowed?
     /// Default is `true`.
@@ -146,8 +152,9 @@ impl Engine {
     }
     /// Set whether variables shadowing is allowed.
     #[inline(always)]
-    pub fn set_allow_shadowing(&mut self, enable: bool) {
+    pub fn set_allow_shadowing(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::SHADOW, enable);
+        self
     }
     /// Is strict variables mode enabled?
     /// Default is `false`.
@@ -158,8 +165,9 @@ impl Engine {
     }
     /// Set whether strict variables mode is enabled.
     #[inline(always)]
-    pub fn set_strict_variables(&mut self, enable: bool) {
+    pub fn set_strict_variables(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::STRICT_VAR, enable);
+        self
     }
     /// Raise error if an object map property does not exist?
     /// Default is `false`.
@@ -177,9 +185,10 @@ impl Engine {
     /// Not available under `no_object`.
     #[cfg(not(feature = "no_object"))]
     #[inline(always)]
-    pub fn set_fail_on_invalid_map_property(&mut self, enable: bool) {
+    pub fn set_fail_on_invalid_map_property(&mut self, enable: bool) -> &mut Self {
         self.options
             .set(LangOptions::FAIL_ON_INVALID_MAP_PROPERTY, enable);
+        self
     }
     /// Is fast operators mode enabled?
     /// Default is `false`.
@@ -190,7 +199,8 @@ impl Engine {
     }
     /// Set whether fast operators mode is enabled.
     #[inline(always)]
-    pub fn set_fast_operators(&mut self, enable: bool) {
+    pub fn set_fast_operators(&mut self, enable: bool) -> &mut Self {
         self.options.set(LangOptions::FAST_OPS, enable);
+        self
     }
 }

src/ast/expr.rs

@@ -624,6 +624,38 @@ impl Expr {
             _ => None,
         }
     }
+    /// Get the [options][ASTFlags] of the expression.
+    #[inline]
+    #[must_use]
+    pub const fn options(&self) -> ASTFlags {
+        match self {
+            Self::Index(_, options, _) | Self::Dot(_, options, _) => *options,
+
+            #[cfg(not(feature = "no_float"))]
+            Self::FloatConstant(..) => ASTFlags::NONE,
+
+            Self::DynamicConstant(..)
+            | Self::BoolConstant(..)
+            | Self::IntegerConstant(..)
+            | Self::CharConstant(..)
+            | Self::Unit(..)
+            | Self::StringConstant(..)
+            | Self::Array(..)
+            | Self::Map(..)
+            | Self::Variable(..)
+            | Self::And(..)
+            | Self::Or(..)
+            | Self::Coalesce(..)
+            | Self::FnCall(..)
+            | Self::MethodCall(..)
+            | Self::InterpolatedString(..)
+            | Self::Property(..)
+            | Self::Stmt(..) => ASTFlags::NONE,
+
+            #[cfg(not(feature = "no_custom_syntax"))]
+            Self::Custom(..) => ASTFlags::NONE,
+        }
+    }
     /// Get the [position][Position] of the expression.
     #[inline]
     #[must_use]

src/ast/stmt.rs

@@ -656,6 +656,34 @@ impl Stmt {
     pub const fn is_noop(&self) -> bool {
         matches!(self, Self::Noop(..))
     }
+    /// Get the [options][ASTFlags] of this statement.
+    #[inline]
+    #[must_use]
+    pub const fn options(&self) -> ASTFlags {
+        match self {
+            Self::Do(_, options, _)
+            | Self::Var(_, options, _)
+            | Self::BreakLoop(_, options, _)
+            | Self::Return(_, options, _) => *options,
+
+            Self::Noop(..)
+            | Self::If(..)
+            | Self::Switch(..)
+            | Self::Block(..)
+            | Self::Expr(..)
+            | Self::FnCall(..)
+            | Self::While(..)
+            | Self::For(..)
+            | Self::TryCatch(..)
+            | Self::Assignment(..) => ASTFlags::NONE,
+
+            #[cfg(not(feature = "no_module"))]
+            Self::Import(..) | Self::Export(..) => ASTFlags::NONE,
+
+            #[cfg(not(feature = "no_closure"))]
+            Self::Share(..) => ASTFlags::NONE,
+        }
+    }
     /// Get the [position][Position] of this statement.
     #[must_use]
     pub fn position(&self) -> Position {

src/config/hashing.rs

@@ -2,7 +2,7 @@
 //!
 //! Set to [`None`] to disable stable hashing.
 //!
-//! See [`set_rhai_ahash_seed`].
+//! See [`rhai::config::hashing::set_ahash_seed`][set_ahash_seed].
 //!
 //! # Example
 //!
@@ -189,7 +189,7 @@ static AHASH_SEED: SusLock<Option<[u64; 4]>> = SusLock::new();
 /// # Warning
 ///
 /// * You can only call this function **ONCE** for the entire duration of program execution.
-/// * You **MUST** call this before performing **ANY** Rhai operation (e.g. creating an [`Engine`]).
+/// * You **MUST** call this before performing **ANY** Rhai operation (e.g. creating an [`Engine`][crate::Engine]).
 ///
 /// # Error
 ///
@@ -216,7 +216,7 @@ pub fn set_ahash_seed(new_seed: Option<[u64; 4]>) -> Result<(), Option<[u64; 4]>
 ///
 /// Otherwise, the hashing seed is randomized to protect against DOS attacks.
 ///
-/// See [`set_rhai_ahash_seed`] for more.
+/// See [`rhai::config::hashing::set_ahash_seed`][set_ahash_seed] for more.
 #[inline]
 #[must_use]
 pub fn get_ahash_seed() -> &'static Option<[u64; 4]> {

src/eval/data_check.rs

@@ -3,7 +3,8 @@
 
 use super::GlobalRuntimeState;
 use crate::types::dynamic::Union;
-use crate::{Dynamic, Engine, Position, RhaiResult, RhaiResultOf, ERR};
+use crate::{Dynamic, Engine, Position, RhaiResultOf, ERR};
+use std::borrow::Borrow;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -70,6 +71,9 @@ impl Engine {
     }
 
     /// Raise an error if any data size exceeds limit.
+    ///
+    /// [`Position`] in [`EvalAltResult`][crate::EvalAltResult] is always [`NONE`][Position::NONE]
+    /// and should be set afterwards.
     pub(crate) fn raise_err_if_over_data_size_limit(
         &self,
         (_arr, _map, s): (usize, usize, usize),
@@ -111,15 +115,20 @@ impl Engine {
 
     /// Check whether the size of a [`Dynamic`] is within limits.
     #[inline]
-    pub(crate) fn check_data_size(&self, value: &Dynamic, pos: Position) -> RhaiResultOf<()> {
+    pub(crate) fn check_data_size<T: Borrow<Dynamic>>(
+        &self,
+        value: T,
+        pos: Position,
+    ) -> RhaiResultOf<T> {
         // If no data size limits, just return
         if !self.has_data_size_limit() {
-            return Ok(());
+            return Ok(value);
         }
 
-        let sizes = Self::calc_data_sizes(value, true);
+        let sizes = Self::calc_data_sizes(value.borrow(), true);
 
         self.raise_err_if_over_data_size_limit(sizes)
+            .map(|_| value)
             .map_err(|err| err.fill_position(pos))
     }
 
@@ -128,7 +137,7 @@ impl Engine {
     /// Not available under `unchecked`.
     #[inline(always)]
     pub fn ensure_data_size_within_limits(&self, value: &Dynamic) -> RhaiResultOf<()> {
-        self.check_data_size(value, Position::NONE)
+        self.check_data_size(value, Position::NONE).map(|_| ())
     }
 
     /// Check if the number of operations stay within limit.
@@ -141,26 +150,15 @@ impl Engine {
 
         // Guard against too many operations
         let max = self.max_operations();
-        let num_operations = global.num_operations;
 
-        if max > 0 && num_operations > max {
+        if max > 0 && global.num_operations > max {
             return Err(ERR::ErrorTooManyOperations(pos).into());
         }
 
         // Report progress
         self.progress
             .as_ref()
-            .and_then(|p| p(num_operations))
+            .and_then(|p| p(global.num_operations))
             .map_or(Ok(()), |token| Err(ERR::ErrorTerminated(token, pos).into()))
     }
-
-    /// Check a result to ensure that it is valid.
-    #[inline]
-    pub(crate) fn check_return_value(&self, result: RhaiResult, pos: Position) -> RhaiResult {
-        if let Ok(ref r) = result {
-            self.check_data_size(r, pos)?;
-        }
-
-        result
-    }
 }

src/eval/eval_context.rs

@@ -1,7 +1,7 @@
 //! Evaluation context.
 
 use super::{Caches, GlobalRuntimeState};
-use crate::{Dynamic, Engine, Module, Scope};
+use crate::{Dynamic, Engine, Scope};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -68,7 +68,7 @@ impl<'a, 's, 'ps, 'g, 'c, 't> EvalContext<'a, 's, 'ps, 'g, 'c, 't> {
     /// in reverse order (i.e. modules imported last come first).
     #[cfg(not(feature = "no_module"))]
     #[inline(always)]
-    pub fn iter_imports(&self) -> impl Iterator<Item = (&str, &Module)> {
+    pub fn iter_imports(&self) -> impl Iterator<Item = (&str, &crate::Module)> {
         self.global.iter_imports()
     }
     /// Custom state kept in a [`Dynamic`].
@@ -104,7 +104,7 @@ impl<'a, 's, 'ps, 'g, 'c, 't> EvalContext<'a, 's, 'ps, 'g, 'c, 't> {
     /// Not available under `no_function`.
     #[cfg(not(feature = "no_function"))]
     #[inline]
-    pub fn iter_namespaces(&self) -> impl Iterator<Item = &Module> {
+    pub fn iter_namespaces(&self) -> impl Iterator<Item = &crate::Module> {
         self.global.lib.iter().map(|m| m.as_ref())
     }
     /// _(internals)_ The current set of namespaces containing definitions of all script-defined functions.

src/eval/expr.rs

@@ -4,7 +4,7 @@ use super::{Caches, EvalContext, GlobalRuntimeState, Target};
 use crate::ast::{Expr, OpAssignment};
 use crate::engine::{KEYWORD_THIS, OP_CONCAT};
 use crate::types::dynamic::AccessMode;
-use crate::{Dynamic, Engine, Position, RhaiResult, RhaiResultOf, Scope, SharedModule, ERR};
+use crate::{Dynamic, Engine, Position, RhaiResult, RhaiResultOf, Scope, ERR};
 use std::num::NonZeroUsize;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -18,23 +18,19 @@ impl Engine {
         &self,
         global: &GlobalRuntimeState,
         namespace: &crate::ast::Namespace,
-    ) -> Option<SharedModule> {
+    ) -> Option<crate::SharedModule> {
         assert!(!namespace.is_empty());
 
         let root = namespace.root();
 
-        let index = if global.always_search_scope {
-            None
-        } else {
-            namespace.index()
-        };
-
         // Qualified - check if the root module is directly indexed
-        if let Some(index) = index {
+        if !global.always_search_scope {
-            let offset = global.num_imports() - index.get();
+            if let Some(index) = namespace.index() {
+                let offset = global.num_imports() - index.get();
 
-            if let m @ Some(_) = global.get_shared_import(offset) {
+                if let m @ Some(_) = global.get_shared_import(offset) {
-                return m;
+                    return m;
+                }
             }
         }
 
@@ -54,12 +50,12 @@ impl Engine {
         scope: &'s mut Scope,
         this_ptr: &'s mut Dynamic,
         expr: &Expr,
-    ) -> RhaiResultOf<(Target<'s>, Position)> {
+    ) -> RhaiResultOf<Target<'s>> {
         match expr {
             Expr::Variable(_, Some(_), _) => {
                 self.search_scope_only(global, caches, scope, this_ptr, expr)
             }
-            Expr::Variable(v, None, _var_pos) => match &**v {
+            Expr::Variable(v, None, ..) => match &**v {
                 // Normal variable access
                 #[cfg(not(feature = "no_module"))]
                 (_, ns, ..) if ns.is_empty() => {
@@ -86,7 +82,7 @@ impl Engine {
                             |mut target| {
                                 // Module variables are constant
                                 target.set_access_mode(AccessMode::ReadOnly);
-                                Ok((target.into(), *_var_pos))
+                                Ok(target.into())
                             },
                         );
                     }
@@ -101,7 +97,7 @@ impl Engine {
                                 let mut target: Target = value.clone().into();
                                 // Module variables are constant
                                 target.set_access_mode(AccessMode::ReadOnly);
-                                return Ok((target, *_var_pos));
+                                return Ok(target);
                             }
                         }
 
@@ -136,23 +132,23 @@ impl Engine {
         scope: &'s mut Scope,
         this_ptr: &'s mut Dynamic,
         expr: &Expr,
-    ) -> RhaiResultOf<(Target<'s>, Position)> {
+    ) -> RhaiResultOf<Target<'s>> {
         // Make sure that the pointer indirection is taken only when absolutely necessary.
 
-        let (index, var_pos) = match expr {
+        let index = match expr {
             // Check if the variable is `this`
-            Expr::Variable(v, None, pos) if v.0.is_none() && v.3 == KEYWORD_THIS => {
+            Expr::Variable(v, None, ..) if v.0.is_none() && v.3 == KEYWORD_THIS => {
                 return if this_ptr.is_null() {
-                    Err(ERR::ErrorUnboundThis(*pos).into())
+                    Err(ERR::ErrorUnboundThis(expr.position()).into())
                 } else {
-                    Ok((this_ptr.into(), *pos))
+                    Ok(this_ptr.into())
                 };
             }
-            _ if global.always_search_scope => (0, expr.start_position()),
+            _ if global.always_search_scope => 0,
-            Expr::Variable(.., Some(i), pos) => (i.get() as usize, *pos),
+            Expr::Variable(_, Some(i), ..) => i.get() as usize,
             // Scripted function with the same name
             #[cfg(not(feature = "no_function"))]
-            Expr::Variable(v, None, pos)
+            Expr::Variable(v, None, ..)
                 if global
                     .lib
                     .iter()
@@ -161,9 +157,9 @@ impl Engine {
             {
                 let val: Dynamic =
                     crate::FnPtr::new_unchecked(v.3.as_str(), Default::default()).into();
-                return Ok((val.into(), *pos));
+                return Ok(val.into());
             }
-            Expr::Variable(v, None, pos) => (v.0.map_or(0, NonZeroUsize::get), *pos),
+            Expr::Variable(v, None, ..) => v.0.map_or(0, NonZeroUsize::get),
             _ => unreachable!("Expr::Variable expected but gets {:?}", expr),
         };
 
@@ -174,10 +170,10 @@ impl Engine {
             match resolve_var(var_name, index, context) {
                 Ok(Some(mut result)) => {
                     result.set_access_mode(AccessMode::ReadOnly);
-                    return Ok((result.into(), var_pos));
+                    return Ok(result.into());
                 }
                 Ok(None) => (),
-                Err(err) => return Err(err.fill_position(var_pos)),
+                Err(err) => return Err(err.fill_position(expr.position())),
             }
         }
 
@@ -191,10 +187,12 @@ impl Engine {
                 Some(index) => index,
                 None => {
                     return match self.global_modules.iter().find_map(|m| m.get_var(var_name)) {
-                        Some(val) => Ok((val.into(), var_pos)),
+                        Some(val) => Ok(val.into()),
-                        None => {
+                        None => Err(ERR::ErrorVariableNotFound(
-                            Err(ERR::ErrorVariableNotFound(var_name.to_string(), var_pos).into())
+                            var_name.to_string(),
-                        }
+                            expr.position(),
+                        )
+                        .into()),
                     }
                 }
             }
@@ -202,17 +200,10 @@ impl Engine {
 
         let val = scope.get_mut_by_index(index);
 
-        Ok((val.into(), var_pos))
+        Ok(val.into())
     }
 
     /// Evaluate an expression.
-    //
-    // # Implementation Notes
-    //
-    // Do not use the `?` operator within the main body as it makes this function return early,
-    // possibly by-passing important cleanup tasks at the end.
-    //
-    // Errors that are not recoverable, such as system errors or safety errors, can use `?`.
     pub(crate) fn eval_expr(
         &self,
         global: &mut GlobalRuntimeState,
@@ -256,7 +247,7 @@ impl Engine {
                 }
             } else {
                 self.search_namespace(global, caches, scope, this_ptr, expr)
-                    .map(|(val, ..)| val.take_or_clone())
+                    .map(Target::take_or_clone)
             };
         }
 
@@ -286,10 +277,8 @@ impl Engine {
                 let target = &mut concat;
 
                 let mut op_info = OpAssignment::new_op_assignment(OP_CONCAT, Position::NONE);
-                let root = ("", Position::NONE);
 
-                let result = x
+                x.iter()
-                    .iter()
                     .try_for_each(|expr| {
                         let item = self
                             .eval_expr(global, caches, scope, this_ptr, expr)?
@@ -297,11 +286,10 @@ impl Engine {
 
                         op_info.pos = expr.start_position();
 
-                        self.eval_op_assignment(global, caches, &op_info, target, root, item)
+                        self.eval_op_assignment(global, caches, &op_info, expr, target, item)
                     })
-                    .map(|_| concat.take_or_clone());
+                    .map(|_| concat.take_or_clone())
-
+                    .and_then(|r| self.check_data_size(r, expr.start_position()))
-                self.check_return_value(result, expr.start_position())
             }
 
             #[cfg(not(feature = "no_index"))]
@@ -414,9 +402,8 @@ impl Engine {
                 })?;
                 let mut context = EvalContext::new(self, global, caches, scope, this_ptr);
 
-                let result = (custom_def.func)(&mut context, &expressions, &custom.state);
+                (custom_def.func)(&mut context, &expressions, &custom.state)
-
+                    .and_then(|r| self.check_data_size(r, expr.start_position()))
-                self.check_return_value(result, expr.start_position())
             }
 
             Expr::Stmt(x) if x.is_empty() => Ok(Dynamic::UNIT),

src/eval/global_state.rs

@@ -1,6 +1,6 @@
 //! Global runtime state.
 
-use crate::{Dynamic, Engine, ImmutableString, SharedModule, StaticVec};
+use crate::{Dynamic, Engine, ImmutableString};
 use std::fmt;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -25,13 +25,13 @@ pub type GlobalConstants =
 pub struct GlobalRuntimeState {
     /// Names of imported [modules][crate::Module].
     #[cfg(not(feature = "no_module"))]
-    imports: StaticVec<ImmutableString>,
+    imports: crate::StaticVec<ImmutableString>,
     /// Stack of imported [modules][crate::Module].
     #[cfg(not(feature = "no_module"))]
-    modules: StaticVec<SharedModule>,
+    modules: crate::StaticVec<crate::SharedModule>,
     /// The current stack of loaded [modules][crate::Module] containing script-defined functions.
     #[cfg(not(feature = "no_function"))]
-    pub lib: StaticVec<SharedModule>,
+    pub lib: crate::StaticVec<crate::SharedModule>,
     /// Source of the current context.
     ///
     /// No source if the string is empty.
@@ -84,11 +84,11 @@ impl GlobalRuntimeState {
     pub fn new(engine: &Engine) -> Self {
         Self {
             #[cfg(not(feature = "no_module"))]
-            imports: StaticVec::new_const(),
+            imports: crate::StaticVec::new_const(),
             #[cfg(not(feature = "no_module"))]
-            modules: StaticVec::new_const(),
+            modules: crate::StaticVec::new_const(),
             #[cfg(not(feature = "no_function"))]
-            lib: StaticVec::new_const(),
+            lib: crate::StaticVec::new_const(),
             source: None,
             num_operations: 0,
             #[cfg(not(feature = "no_module"))]
@@ -99,7 +99,10 @@ impl GlobalRuntimeState {
             #[cfg(not(feature = "no_module"))]
             embedded_module_resolver: None,
             #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
-            fn_hash_indexing: (0, 0),
+            fn_hash_indexing: (
+                crate::calc_fn_hash(None, crate::engine::FN_IDX_GET, 2),
+                crate::calc_fn_hash(None, crate::engine::FN_IDX_SET, 3),
+            ),
             #[cfg(not(feature = "no_module"))]
             #[cfg(not(feature = "no_function"))]
             constants: None,
@@ -135,7 +138,7 @@ impl GlobalRuntimeState {
     #[cfg(not(feature = "no_module"))]
     #[inline(always)]
     #[must_use]
-    pub fn get_shared_import(&self, index: usize) -> Option<SharedModule> {
+    pub fn get_shared_import(&self, index: usize) -> Option<crate::SharedModule> {
         self.modules.get(index).cloned()
     }
     /// Get a mutable reference to the globally-imported [module][crate::Module] at a
@@ -146,7 +149,10 @@ impl GlobalRuntimeState {
     #[allow(dead_code)]
     #[inline(always)]
     #[must_use]
-    pub(crate) fn get_shared_import_mut(&mut self, index: usize) -> Option<&mut SharedModule> {
+    pub(crate) fn get_shared_import_mut(
+        &mut self,
+        index: usize,
+    ) -> Option<&mut crate::SharedModule> {
         self.modules.get_mut(index)
     }
     /// Get the index of a globally-imported [module][crate::Module] by name.
@@ -170,7 +176,7 @@ impl GlobalRuntimeState {
     pub fn push_import(
         &mut self,
         name: impl Into<ImmutableString>,
-        module: impl Into<SharedModule>,
+        module: impl Into<crate::SharedModule>,
     ) {
         self.imports.push(name.into());
         self.modules.push(module.into());
@@ -203,7 +209,7 @@ impl GlobalRuntimeState {
     #[inline]
     pub(crate) fn iter_imports_raw(
         &self,
-    ) -> impl Iterator<Item = (&ImmutableString, &SharedModule)> {
+    ) -> impl Iterator<Item = (&ImmutableString, &crate::SharedModule)> {
         self.imports.iter().zip(self.modules.iter()).rev()
     }
     /// Get an iterator to the stack of globally-imported [modules][crate::Module] in forward order.
@@ -211,7 +217,9 @@ impl GlobalRuntimeState {
     /// Not available under `no_module`.
     #[cfg(not(feature = "no_module"))]
     #[inline]
-    pub fn scan_imports_raw(&self) -> impl Iterator<Item = (&ImmutableString, &SharedModule)> {
+    pub fn scan_imports_raw(
+        &self,
+    ) -> impl Iterator<Item = (&ImmutableString, &crate::SharedModule)> {
         self.imports.iter().zip(self.modules.iter())
     }
     /// Can the particular function with [`Dynamic`] parameter(s) exist in the stack of
@@ -291,34 +299,22 @@ impl GlobalRuntimeState {
     }
     /// Get the pre-calculated index getter hash.
     #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
+    #[inline(always)]
     #[must_use]
     pub(crate) fn hash_idx_get(&mut self) -> u64 {
-        if self.fn_hash_indexing == (0, 0) {
+        self.fn_hash_indexing.0
-            let n1 = crate::calc_fn_hash(None, crate::engine::FN_IDX_GET, 2);
-            let n2 = crate::calc_fn_hash(None, crate::engine::FN_IDX_SET, 3);
-            self.fn_hash_indexing = (n1, n2);
-            n1
-        } else {
-            self.fn_hash_indexing.0
-        }
     }
     /// Get the pre-calculated index setter hash.
     #[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
+    #[inline(always)]
     #[must_use]
     pub(crate) fn hash_idx_set(&mut self) -> u64 {
-        if self.fn_hash_indexing == (0, 0) {
+        self.fn_hash_indexing.1
-            let n1 = crate::calc_fn_hash(None, crate::engine::FN_IDX_GET, 2);
-            let n2 = crate::calc_fn_hash(None, crate::engine::FN_IDX_SET, 3);
-            self.fn_hash_indexing = (n1, n2);
-            n2
-        } else {
-            self.fn_hash_indexing.1
-        }
     }
 }
 
 #[cfg(not(feature = "no_module"))]
-impl<K: Into<ImmutableString>, M: Into<SharedModule>> Extend<(K, M)> for GlobalRuntimeState {
+impl<K: Into<ImmutableString>, M: Into<crate::SharedModule>> Extend<(K, M)> for GlobalRuntimeState {
     #[inline]
     fn extend<T: IntoIterator<Item = (K, M)>>(&mut self, iter: T) {
         for (k, m) in iter {

src/eval/mod.rs

@@ -25,7 +25,10 @@ pub use target::{calc_index, calc_offset_len, Target};
 
 #[cfg(feature = "unchecked")]
 mod unchecked {
-    use crate::{eval::GlobalRuntimeState, Dynamic, Engine, Position, RhaiResult, RhaiResultOf};
+    use crate::{eval::GlobalRuntimeState, Dynamic, Engine, Position, RhaiResultOf};
+    use std::borrow::Borrow;
+    #[cfg(feature = "no_std")]
+    use std::prelude::v1::*;
 
     impl Engine {
         /// Check if the number of operations stay within limit.
@@ -40,18 +43,12 @@ mod unchecked {
 
         /// Check whether the size of a [`Dynamic`] is within limits.
         #[inline(always)]
-        pub(crate) const fn check_data_size(&self, _: &Dynamic, _: Position) -> RhaiResultOf<()> {
+        pub(crate) const fn check_data_size<T: Borrow<Dynamic>>(
-            Ok(())
-        }
-
-        /// Check a result to ensure that it is valid.
-        #[inline(always)]
-        pub(crate) const fn check_return_value(
             &self,
-            result: RhaiResult,
+            value: T,
             _: Position,
-        ) -> RhaiResult {
+        ) -> RhaiResultOf<T> {
-            result
+            Ok(value)
         }
     }
 }

src/eval/stmt.rs

@@ -8,22 +8,13 @@ use crate::ast::{
 use crate::func::{get_builtin_op_assignment_fn, get_hasher};
 use crate::types::dynamic::AccessMode;
 use crate::types::RestoreOnDrop;
-use crate::{
+use crate::{Dynamic, Engine, RhaiResult, RhaiResultOf, Scope, ERR, INT};
-    Dynamic, Engine, ImmutableString, Position, RhaiResult, RhaiResultOf, Scope, ERR, INT,
-};
 use std::hash::{Hash, Hasher};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
 impl Engine {
     /// Evaluate a statements block.
-    //
-    // # Implementation Notes
-    //
-    // Do not use the `?` operator within the main body as it makes this function return early,
-    // possibly by-passing important cleanup tasks at the end.
-    //
-    // Errors that are not recoverable, such as system errors or safety errors, can use `?`.
     pub(crate) fn eval_stmt_block(
         &self,
         global: &mut GlobalRuntimeState,
@@ -112,13 +103,15 @@ impl Engine {
         global: &mut GlobalRuntimeState,
         caches: &mut Caches,
         op_info: &OpAssignment,
+        root: &Expr,
         target: &mut Target,
-        root: (&str, Position),
         mut new_val: Dynamic,
     ) -> RhaiResultOf<()> {
         // Assignment to constant variable?
         if target.is_read_only() {
-            return Err(ERR::ErrorAssignmentToConstant(root.0.to_string(), root.1).into());
+            let name = root.get_variable_name(false).unwrap_or_default();
+            let pos = root.start_position();
+            return Err(ERR::ErrorAssignmentToConstant(name.to_string(), pos).into());
         }
 
         if op_info.is_op_assignment() {
@@ -166,14 +159,13 @@ impl Engine {
                     *args[0] = self
                         .exec_native_fn_call(
                             global, caches, op, token, *hash_op, args, true, *op_pos,
-                        )
+                        )?
-                        .map_err(|err| err.fill_position(op_info.pos))?
                         .0;
                 }
                 Err(err) => return Err(err),
             }
 
-            self.check_data_size(args[0], root.1)?;
+            self.check_data_size(&*args[0], root.position())?;
         } else {
             // Normal assignment
 
@@ -190,13 +182,6 @@ impl Engine {
     }
 
     /// Evaluate a statement.
-    //
-    // # Implementation Notes
-    //
-    // Do not use the `?` operator within the main body as it makes this function return early,
-    // possibly by-passing important cleanup tasks at the end.
-    //
-    // Errors that are not recoverable, such as system errors or safety errors, can use `?`.
     pub(crate) fn eval_stmt(
         &self,
         global: &mut GlobalRuntimeState,
@@ -234,29 +219,29 @@ impl Engine {
                     .eval_expr(global, caches, scope, this_ptr, rhs)?
                     .flatten();
 
-                let (mut lhs_ptr, pos) =
+                let mut target = self.search_namespace(global, caches, scope, this_ptr, lhs)?;
-                    self.search_namespace(global, caches, scope, this_ptr, lhs)?;
 
                 let var_name = x.3.as_str();
 
                 #[cfg(not(feature = "no_closure"))]
                 // Also handle case where target is a `Dynamic` shared value
                 // (returned by a variable resolver, for example)
-                let is_temp_result = !lhs_ptr.is_ref() && !lhs_ptr.is_shared();
+                let is_temp_result = !target.is_ref() && !target.is_shared();
                 #[cfg(feature = "no_closure")]
-                let is_temp_result = !lhs_ptr.is_ref();
+                let is_temp_result = !target.is_ref();
 
                 // Cannot assign to temp result from expression
                 if is_temp_result {
-                    return Err(ERR::ErrorAssignmentToConstant(var_name.to_string(), pos).into());
+                    return Err(ERR::ErrorAssignmentToConstant(
+                        var_name.to_string(),
+                        lhs.position(),
+                    )
+                    .into());
                 }
 
-                self.track_operation(global, pos)?;
+                self.track_operation(global, lhs.position())?;
 
-                let root = (var_name, pos);
+                self.eval_op_assignment(global, caches, op_info, lhs, &mut target, rhs_val)?;
-                let lhs_ptr = &mut lhs_ptr;
-
-                self.eval_op_assignment(global, caches, op_info, lhs_ptr, root, rhs_val)?;
 
                 return Ok(Dynamic::UNIT);
             }
@@ -788,8 +773,8 @@ impl Engine {
 
                 let v = self.eval_expr(global, caches, scope, this_ptr, expr)?;
                 let typ = v.type_name();
-                let path = v.try_cast::<ImmutableString>().ok_or_else(|| {
+                let path = v.try_cast::<crate::ImmutableString>().ok_or_else(|| {
-                    self.make_type_mismatch_err::<ImmutableString>(typ, expr.position())
+                    self.make_type_mismatch_err::<crate::ImmutableString>(typ, expr.position())
                 })?;
 
                 use crate::ModuleResolver;

src/eval/target.rs

@@ -1,6 +1,5 @@
 //! Type to hold a mutable reference to the target of an evaluation.
 
-use crate::types::dynamic::Variant;
 use crate::{Dynamic, Position, RhaiResultOf};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
@@ -52,26 +51,23 @@ pub fn calc_index<E>(
     length: usize,
     start: crate::INT,
     negative_count_from_end: bool,
-    err: impl FnOnce() -> Result<usize, E>,
+    err_func: impl FnOnce() -> Result<usize, E>,
 ) -> Result<usize, E> {
     if start < 0 {
         if negative_count_from_end {
             let abs_start = start.unsigned_abs() as usize;
 
             // Count from end if negative
-            if abs_start > length {
+            if abs_start <= length {
-                err()
+                return Ok(length - abs_start);
-            } else {
-                Ok(length - abs_start)
             }
-        } else {
-            err()
         }
-    } else if start > crate::MAX_USIZE_INT || start as usize >= length {
-        err()
-    } else {
-        Ok(start as usize)
     }
+    if start <= crate::MAX_USIZE_INT && (start as usize) < length {
+        return Ok(start as usize);
+    }
+
+    err_func()
 }
 
 /// A type that encapsulates a mutation target for an expression with side effects.
@@ -180,7 +176,7 @@ impl<'a> Target<'a> {
             Self::RefMut(r) => r.is_shared(),
             #[cfg(not(feature = "no_closure"))]
             Self::SharedValue { .. } => true,
-            Self::TempValue(r) => r.is_shared(),
+            Self::TempValue(value) => value.is_shared(),
             #[cfg(not(feature = "no_index"))]
             Self::Bit { .. }
             | Self::BitField { .. }
@@ -188,29 +184,6 @@ impl<'a> Target<'a> {
             | Self::StringChar { .. } => false,
         }
     }
-    /// Is the [`Target`] a specific type?
-    #[allow(dead_code)]
-    #[inline]
-    #[must_use]
-    pub fn is<T: Variant + Clone>(&self) -> bool {
-        #[allow(unused_imports)]
-        use std::any::TypeId;
-
-        match self {
-            Self::RefMut(r) => r.is::<T>(),
-            #[cfg(not(feature = "no_closure"))]
-            Self::SharedValue { source, .. } => source.is::<T>(),
-            Self::TempValue(r) => r.is::<T>(),
-            #[cfg(not(feature = "no_index"))]
-            Self::Bit { .. } => TypeId::of::<T>() == TypeId::of::<bool>(),
-            #[cfg(not(feature = "no_index"))]
-            Self::BitField { .. } => TypeId::of::<T>() == TypeId::of::<crate::INT>(),
-            #[cfg(not(feature = "no_index"))]
-            Self::BlobByte { .. } => TypeId::of::<T>() == TypeId::of::<crate::Blob>(),
-            #[cfg(not(feature = "no_index"))]
-            Self::StringChar { .. } => TypeId::of::<T>() == TypeId::of::<char>(),
-        }
-    }
     /// Get the value of the [`Target`] as a [`Dynamic`], cloning a referenced value if necessary.
     #[inline]
     #[must_use]
@@ -219,7 +192,7 @@ impl<'a> Target<'a> {
             Self::RefMut(r) => r.clone(), // Referenced value is cloned
             #[cfg(not(feature = "no_closure"))]
             Self::SharedValue { value, .. } => value, // Original shared value is simply taken
-            Self::TempValue(v) => v,      // Owned value is simply taken
+            Self::TempValue(value) => value, // Owned value is simply taken
             #[cfg(not(feature = "no_index"))]
             Self::Bit { value, .. } => value, // boolean is taken
             #[cfg(not(feature = "no_index"))]
@@ -259,7 +232,7 @@ impl<'a> Target<'a> {
             Self::RefMut(r) => r,
             #[cfg(not(feature = "no_closure"))]
             Self::SharedValue { source, .. } => source,
-            Self::TempValue(v) => v,
+            Self::TempValue(value) => value,
             #[cfg(not(feature = "no_index"))]
             Self::Bit { source, .. } => source,
             #[cfg(not(feature = "no_index"))]
@@ -342,13 +315,7 @@ impl<'a> Target<'a> {
 
                 let value = &mut *source.write_lock::<crate::Blob>().expect("`Blob`");
 
-                let index = *index;
+                value[*index] = (new_byte & 0x00ff) as u8;
-
-                if index < value.len() {
-                    value[index] = (new_byte & 0x00ff) as u8;
-                } else {
-                    unreachable!("blob index out of bounds: {}", index);
-                }
             }
             #[cfg(not(feature = "no_index"))]
             Self::StringChar {
@@ -369,12 +336,10 @@ impl<'a> Target<'a> {
                     .write_lock::<crate::ImmutableString>()
                     .expect("`ImmutableString`");
 
-                let index = *index;
-
                 *s = s
                     .chars()
                     .enumerate()
-                    .map(|(i, ch)| if i == index { new_ch } else { ch })
+                    .map(|(i, ch)| if i == *index { new_ch } else { ch })
                     .collect();
             }
         }
@@ -407,7 +372,7 @@ impl Deref for Target<'_> {
             Self::RefMut(r) => r,
             #[cfg(not(feature = "no_closure"))]
             Self::SharedValue { source, .. } => source,
-            Self::TempValue(ref r) => r,
+            Self::TempValue(ref value) => value,
             #[cfg(not(feature = "no_index"))]
             Self::Bit { ref value, .. }
             | Self::BitField { ref value, .. }
@@ -440,7 +405,7 @@ impl DerefMut for Target<'_> {
             Self::RefMut(r) => r,
             #[cfg(not(feature = "no_closure"))]
             Self::SharedValue { source, .. } => &mut *source,
-            Self::TempValue(ref mut r) => r,
+            Self::TempValue(ref mut value) => value,
             #[cfg(not(feature = "no_index"))]
             Self::Bit { ref mut value, .. }
             | Self::BitField { ref mut value, .. }

src/func/args.rs

@@ -66,6 +66,13 @@ impl<T: Variant + Clone> FuncArgs for Vec<T> {
     }
 }
 
+impl<T: Variant + Clone, const N: usize> FuncArgs for [T; N] {
+    #[inline]
+    fn parse<ARGS: Extend<Dynamic>>(self, args: &mut ARGS) {
+        args.extend(IntoIterator::into_iter(self).map(Dynamic::from));
+    }
+}
+
 /// Macro to implement [`FuncArgs`] for tuples of standard types (each can be converted into a [`Dynamic`]).
 macro_rules! impl_args {
     ($($p:ident),*) => {

src/func/call.rs

@@ -12,7 +12,7 @@ use crate::tokenizer::{is_valid_function_name, Token};
 use crate::types::RestoreOnDrop;
 use crate::{
     calc_fn_hash, calc_fn_hash_full, Dynamic, Engine, FnArgsVec, FnPtr, ImmutableString,
-    OptimizationLevel, Position, RhaiError, RhaiResult, RhaiResultOf, Scope, ERR,
+    OptimizationLevel, Position, RhaiError, RhaiResult, RhaiResultOf, Scope, Shared, ERR,
 };
 #[cfg(feature = "no_std")]
 use hashbrown::hash_map::Entry;
@@ -166,7 +166,7 @@ impl Engine {
     #[must_use]
     fn resolve_fn<'s>(
         &self,
-        global: &GlobalRuntimeState,
+        _global: &GlobalRuntimeState,
         caches: &'s mut Caches,
         local_entry: &'s mut Option<FnResolutionCacheEntry>,
         op_token: Option<&Token>,
@@ -194,7 +194,7 @@ impl Engine {
 
                 loop {
                     #[cfg(not(feature = "no_function"))]
-                    let func = global
+                    let func = _global
                         .lib
                         .iter()
                         .rev()
@@ -214,7 +214,7 @@ impl Engine {
                         // Scripted functions are not exposed globally
                         func
                     } else {
-                        func.or_else(|| global.get_qualified_fn(hash)).or_else(|| {
+                        func.or_else(|| _global.get_qualified_fn(hash)).or_else(|| {
                             self.global_sub_modules
                                 .values()
                                 .find_map(|m| m.get_qualified_fn(hash).map(|f| (f, m.id_raw())))
@@ -223,17 +223,17 @@ impl Engine {
 
                     if let Some((f, s)) = func {
                         // Specific version found
-                        let new_entry = Some(FnResolutionCacheEntry {
+                        let new_entry = FnResolutionCacheEntry {
                             func: f.clone(),
                             source: s.cloned(),
-                        });
+                        };
                         return if cache.filter.is_absent_and_set(hash) {
                             // Do not cache "one-hit wonders"
-                            *local_entry = new_entry;
+                            *local_entry = Some(new_entry);
                             local_entry.as_ref()
                         } else {
                             // Cache entry
-                            entry.insert(new_entry).as_ref()
+                            entry.insert(Some(new_entry)).as_ref()
                         };
                     }
 
@@ -246,14 +246,14 @@ impl Engine {
 
                         #[cfg(not(feature = "no_function"))]
                         let is_dynamic = is_dynamic
-                            || global
+                            || _global
                                 .lib
                                 .iter()
                                 .any(|m| m.may_contain_dynamic_fn(hash_base));
 
                         #[cfg(not(feature = "no_module"))]
                         let is_dynamic = is_dynamic
-                            || global.may_contain_dynamic_fn(hash_base)
+                            || _global.may_contain_dynamic_fn(hash_base)
                             || self
                                 .global_sub_modules
                                 .values()
@@ -279,13 +279,13 @@ impl Engine {
 
                                     get_builtin_op_assignment_fn(token, *first_arg, rest_args[0])
                                         .map(|f| FnResolutionCacheEntry {
-                                            func: CallableFunction::from_fn_builtin(f),
+                                            func: CallableFunction::Method(Shared::new(f)),
                                             source: None,
                                         })
                                 }
                                 Some(token) => get_builtin_binary_op_fn(token, args[0], args[1])
                                     .map(|f| FnResolutionCacheEntry {
-                                        func: CallableFunction::from_fn_builtin(f),
+                                        func: CallableFunction::Method(Shared::new(f)),
                                         source: None,
                                     }),
 
@@ -363,16 +363,13 @@ impl Engine {
             true,
         );
 
-        if func.is_some() {
+        if let Some(FnResolutionCacheEntry { func, source }) = func {
-            let is_method = func.map_or(false, |f| f.func.is_method());
+            assert!(func.is_native());
 
             // Push a new call stack frame
             #[cfg(feature = "debugging")]
             let orig_call_stack_len = global.debugger.call_stack().len();
 
-            let FnResolutionCacheEntry { func, source } = func.unwrap();
-            assert!(func.is_native());
-
             let backup = &mut ArgBackup::new();
 
             // Calling pure function but the first argument is a reference?
@@ -397,6 +394,7 @@ impl Engine {
             }
 
             // Run external function
+            let is_method = func.is_method();
             let src = source.as_ref().map(|s| s.as_str());
             let context = (self, name, src, &*global, pos).into();
 
@@ -406,16 +404,22 @@ impl Engine {
                     Err(ERR::ErrorNonPureMethodCallOnConstant(name.to_string(), pos).into())
                 } else {
                     f.call(context, args)
+                        .and_then(|r| self.check_data_size(r, pos))
+                        .map_err(|err| err.fill_position(pos))
                 }
             } else {
                 func.get_native_fn().unwrap()(context, args)
+                    .and_then(|r| self.check_data_size(r, pos))
+                    .map_err(|err| err.fill_position(pos))
             };
 
             #[cfg(feature = "debugging")]
             {
+                use crate::eval::{DebuggerEvent, DebuggerStatus};
+
                 let trigger = match global.debugger.status {
-                    crate::eval::DebuggerStatus::FunctionExit(n) => n >= global.level,
+                    DebuggerStatus::FunctionExit(n) => n >= global.level,
-                    crate::eval::DebuggerStatus::Next(.., true) => true,
+                    DebuggerStatus::Next(.., true) => true,
                     _ => false,
                 };
                 if trigger {
@@ -424,8 +428,8 @@ impl Engine {
                     let node = crate::ast::Stmt::Noop(pos);
                     let node = (&node).into();
                     let event = match _result {
-                        Ok(ref r) => crate::eval::DebuggerEvent::FunctionExitWithValue(r),
+                        Ok(ref r) => DebuggerEvent::FunctionExitWithValue(r),
-                        Err(ref err) => crate::eval::DebuggerEvent::FunctionExitWithError(err),
+                        Err(ref err) => DebuggerEvent::FunctionExitWithError(err),
                     };
 
                     if let Err(err) =
@@ -439,13 +443,12 @@ impl Engine {
                 global.debugger.rewind_call_stack(orig_call_stack_len);
             }
 
-            // Check the return value (including data sizes)
+            let result = _result?;
-            let result = self.check_return_value(_result, pos)?;
 
             // Check the data size of any `&mut` object, which may be changed.
             #[cfg(not(feature = "unchecked"))]
             if is_ref_mut && !args.is_empty() {
-                self.check_data_size(args[0], pos)?;
+                self.check_data_size(&*args[0], pos)?;
             }
 
             // See if the function match print/debug (which requires special processing)
@@ -1188,14 +1191,14 @@ impl Engine {
                         .map(|(value, ..)| arg_values.push(value.flatten()))
                 })?;
 
-                let (mut target, _pos) =
+                let mut target =
                     self.search_namespace(global, caches, scope, this_ptr, first_expr)?;
 
                 if target.is_read_only() {
                     target = target.into_owned();
                 }
 
-                self.track_operation(global, _pos)?;
+                self.track_operation(global, first_expr.position())?;
 
                 #[cfg(not(feature = "no_closure"))]
                 let target_is_shared = target.is_shared();
@@ -1269,10 +1272,9 @@ impl Engine {
 
                 // Get target reference to first argument
                 let first_arg = &args_expr[0];
-                let (target, _pos) =
+                let target = self.search_scope_only(global, caches, scope, this_ptr, first_arg)?;
-                    self.search_scope_only(global, caches, scope, this_ptr, first_arg)?;
 
-                self.track_operation(global, _pos)?;
+                self.track_operation(global, first_arg.position())?;
 
                 #[cfg(not(feature = "no_closure"))]
                 let target_is_shared = target.is_shared();
@@ -1382,19 +1384,18 @@ impl Engine {
             Some(f) if f.is_plugin_fn() => {
                 let context = (self, fn_name, module.id(), &*global, pos).into();
                 let f = f.get_plugin_fn().expect("plugin function");
-                let result = if !f.is_pure() && !args.is_empty() && args[0].is_read_only() {
+                if !f.is_pure() && !args.is_empty() && args[0].is_read_only() {
                     Err(ERR::ErrorNonPureMethodCallOnConstant(fn_name.to_string(), pos).into())
                 } else {
                     f.call(context, &mut args)
-                };
+                        .and_then(|r| self.check_data_size(r, pos))
-                self.check_return_value(result, pos)
+                }
             }
 
             Some(f) if f.is_native() => {
                 let func = f.get_native_fn().expect("native function");
                 let context = (self, fn_name, module.id(), &*global, pos).into();
-                let result = func(context, &mut args);
+                func(context, &mut args).and_then(|r| self.check_data_size(r, pos))
-                self.check_return_value(result, pos)
             }
 
             Some(f) => unreachable!("unknown function type: {:?}", f),

src/func/callable_function.rs

@@ -1,6 +1,6 @@
 //! Module defining the standard Rhai function type.
 
-use super::native::{FnAny, FnBuiltin, FnPlugin, IteratorFn, SendSync};
+use super::native::{FnAny, FnPlugin, IteratorFn, SendSync};
 use crate::ast::FnAccess;
 use crate::plugin::PluginFunction;
 use crate::Shared;
@@ -8,7 +8,8 @@ use std::fmt;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
-/// A type encapsulating a function callable by Rhai.
+/// _(internals)_ A type encapsulating a function callable by Rhai.
+/// Exported under the `internals` feature only.
 #[derive(Clone)]
 #[non_exhaustive]
 pub enum CallableFunction {
@@ -199,18 +200,6 @@ impl CallableFunction {
             Self::Script(..) => None,
         }
     }
-    /// Create a new [`CallableFunction::Method`] from a built-in function.
-    #[inline(always)]
-    #[must_use]
-    pub fn from_fn_builtin(func: FnBuiltin) -> Self {
-        Self::Method(Shared::new(func))
-    }
-    /// Create a new [`CallableFunction::Plugin`].
-    #[inline(always)]
-    #[must_use]
-    pub fn from_plugin(func: impl PluginFunction + 'static + SendSync) -> Self {
-        Self::Plugin(Shared::new(func))
-    }
 }
 
 #[cfg(not(feature = "no_function"))]
@@ -232,7 +221,7 @@ impl From<Shared<crate::ast::ScriptFnDef>> for CallableFunction {
 impl<T: PluginFunction + 'static + SendSync> From<T> for CallableFunction {
     #[inline(always)]
     fn from(func: T) -> Self {
-        Self::from_plugin(func)
+        Self::Plugin(Shared::new(func))
     }
 }
 

src/func/hashing.rs

@@ -92,7 +92,7 @@ pub fn get_hasher() -> ahash::AHasher {
 ///
 /// # Zeros
 ///
-/// If the hash happens to be zero, it is mapped to `DEFAULT_HASH`.
+/// If the hash happens to be zero, it is mapped to `ALT_ZERO_HASH`.
 ///
 /// # Note
 ///
@@ -107,9 +107,8 @@ pub fn calc_var_hash<'a>(
 
     // We always skip the first module
     let iter = modules.into_iter();
-    let len = iter.len();
+    iter.len().hash(s);
     iter.skip(1).for_each(|m| m.hash(s));
-    len.hash(s);
     var_name.hash(s);
 
     match s.finish() {
@@ -128,7 +127,7 @@ pub fn calc_var_hash<'a>(
 ///
 /// # Zeros
 ///
-/// If the hash happens to be zero, it is mapped to `DEFAULT_HASH`.
+/// If the hash happens to be zero, it is mapped to `ALT_ZERO_HASH`.
 ///
 /// # Note
 ///
@@ -144,9 +143,8 @@ pub fn calc_fn_hash<'a>(
 
     // We always skip the first module
     let iter = namespace.into_iter();
-    let len = iter.len();
+    iter.len().hash(s);
     iter.skip(1).for_each(|m| m.hash(s));
-    len.hash(s);
     fn_name.hash(s);
     num.hash(s);
 
@@ -162,7 +160,7 @@ pub fn calc_fn_hash<'a>(
 ///
 /// # Zeros
 ///
-/// If the hash happens to be zero, it is mapped to `DEFAULT_HASH`.
+/// If the hash happens to be zero, it is mapped to `ALT_ZERO_HASH`.
 #[inline]
 #[must_use]
 pub fn calc_fn_hash_full(
@@ -172,11 +170,10 @@ pub fn calc_fn_hash_full(
     let s = &mut get_hasher();
     base.hash(s);
     let iter = params.into_iter();
-    let len = iter.len();
+    iter.len().hash(s);
     iter.for_each(|t| {
         t.hash(s);
     });
-    len.hash(s);
 
     match s.finish() {
         0 => ALT_ZERO_HASH,

src/func/native.rs

@@ -7,10 +7,10 @@ use crate::plugin::PluginFunction;
 use crate::tokenizer::{is_valid_function_name, Token, TokenizeState};
 use crate::types::dynamic::Variant;
 use crate::{
-    calc_fn_hash, Dynamic, Engine, EvalContext, FuncArgs, Module, Position, RhaiResult,
+    calc_fn_hash, reify, Dynamic, Engine, EvalContext, FuncArgs, Position, RhaiResult,
-    RhaiResultOf, SharedModule, StaticVec, VarDefInfo, ERR,
+    RhaiResultOf, StaticVec, VarDefInfo, ERR,
 };
-use std::any::type_name;
+use std::any::{type_name, TypeId};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -100,7 +100,7 @@ pub struct NativeCallContextStore {
 #[cfg(feature = "internals")]
 #[allow(deprecated)]
 impl NativeCallContextStore {
-    /// Create a [`NativeCallContext`] from a [`NativeCallContextClone`].
+    /// Create a [`NativeCallContext`] from a [`NativeCallContextStore`].
     ///
     /// # WARNING - Unstable API
     ///
@@ -167,7 +167,7 @@ impl<'a> NativeCallContext<'a> {
         }
     }
 
-    /// _(internals)_ Create a [`NativeCallContext`] from a [`NativeCallContextClone`].
+    /// _(internals)_ Create a [`NativeCallContext`] from a [`NativeCallContextStore`].
     /// Exported under the `internals` feature only.
     ///
     /// # WARNING - Unstable API
@@ -187,7 +187,7 @@ impl<'a> NativeCallContext<'a> {
             pos: context.pos,
         }
     }
-    /// _(internals)_ Store this [`NativeCallContext`] into a [`NativeCallContextClone`].
+    /// _(internals)_ Store this [`NativeCallContext`] into a [`NativeCallContextStore`].
     /// Exported under the `internals` feature only.
     ///
     /// # WARNING - Unstable API
@@ -249,7 +249,7 @@ impl<'a> NativeCallContext<'a> {
     /// Not available under `no_module`.
     #[cfg(not(feature = "no_module"))]
     #[inline]
-    pub fn iter_imports(&self) -> impl Iterator<Item = (&str, &Module)> {
+    pub fn iter_imports(&self) -> impl Iterator<Item = (&str, &crate::Module)> {
         self.global.iter_imports()
     }
     /// Get an iterator over the current set of modules imported via `import` statements in reverse order.
@@ -258,7 +258,7 @@ impl<'a> NativeCallContext<'a> {
     #[inline]
     pub(crate) fn iter_imports_raw(
         &self,
-    ) -> impl Iterator<Item = (&crate::ImmutableString, &SharedModule)> {
+    ) -> impl Iterator<Item = (&crate::ImmutableString, &crate::SharedModule)> {
         self.global.iter_imports_raw()
     }
     /// _(internals)_ The current [`GlobalRuntimeState`], if any.
@@ -277,7 +277,7 @@ impl<'a> NativeCallContext<'a> {
     /// Not available under `no_function`.
     #[cfg(not(feature = "no_function"))]
     #[inline]
-    pub fn iter_namespaces(&self) -> impl Iterator<Item = &Module> {
+    pub fn iter_namespaces(&self) -> impl Iterator<Item = &crate::Module> {
         self.global.lib.iter().map(|m| m.as_ref())
     }
     /// _(internals)_ The current stack of namespaces containing definitions of all script-defined functions.
@@ -288,7 +288,7 @@ impl<'a> NativeCallContext<'a> {
     #[cfg(feature = "internals")]
     #[inline(always)]
     #[must_use]
-    pub fn namespaces(&self) -> &[SharedModule] {
+    pub fn namespaces(&self) -> &[crate::SharedModule] {
         &self.global.lib
     }
     /// Call a function inside the call context with the provided arguments.
@@ -303,7 +303,12 @@ impl<'a> NativeCallContext<'a> {
 
         let mut args: StaticVec<_> = arg_values.iter_mut().collect();
 
-        let result = self._call_fn_raw(fn_name, false, false, false, &mut args)?;
+        let result = self._call_fn_raw(fn_name, &mut args, false, false, false)?;
+
+        // Bail out early if the return type needs no cast
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return Ok(reify!(result => T));
+        }
 
         let typ = self.engine().map_type_name(result.type_name());
 
@@ -328,7 +333,12 @@ impl<'a> NativeCallContext<'a> {
 
         let mut args: StaticVec<_> = arg_values.iter_mut().collect();
 
-        let result = self._call_fn_raw(fn_name, true, false, false, &mut args)?;
+        let result = self._call_fn_raw(fn_name, &mut args, true, false, false)?;
+
+        // Bail out early if the return type needs no cast
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return Ok(reify!(result => T));
+        }
 
         let typ = self.engine().map_type_name(result.type_name());
 
@@ -369,7 +379,7 @@ impl<'a> NativeCallContext<'a> {
         #[cfg(not(feature = "no_function"))]
         let native_only = native_only && !crate::parser::is_anonymous_fn(name);
 
-        self._call_fn_raw(fn_name, native_only, is_ref_mut, is_method_call, args)
+        self._call_fn_raw(fn_name, args, native_only, is_ref_mut, is_method_call)
     }
     /// Call a registered native Rust function inside the call context.
     ///
@@ -398,17 +408,17 @@ impl<'a> NativeCallContext<'a> {
         is_ref_mut: bool,
         args: &mut [&mut Dynamic],
     ) -> RhaiResult {
-        self._call_fn_raw(fn_name, true, is_ref_mut, false, args)
+        self._call_fn_raw(fn_name, args, true, is_ref_mut, false)
     }
 
     /// Call a function (native Rust or scripted) inside the call context.
     fn _call_fn_raw(
         &self,
         fn_name: impl AsRef<str>,
+        args: &mut [&mut Dynamic],
         native_only: bool,
         is_ref_mut: bool,
         is_method_call: bool,
-        args: &mut [&mut Dynamic],
     ) -> RhaiResult {
         let mut global = &mut self.global.clone();
         let caches = &mut Caches::new();
@@ -509,7 +519,8 @@ pub fn shared_take<T>(value: Shared<T>) -> T {
     shared_try_take(value).ok().expect("not shared")
 }
 
-/// Lock a [`Locked`] resource for mutable access.
+/// _(internals)_ Lock a [`Locked`] resource for mutable access.
+/// Exported under the `internals` feature only.
 #[inline(always)]
 #[must_use]
 #[allow(dead_code)]
@@ -521,7 +532,8 @@ pub fn locked_read<T>(value: &Locked<T>) -> LockGuard<T> {
     return value.read().unwrap();
 }
 
-/// Lock a [`Locked`] resource for mutable access.
+/// _(internals)_ Lock a [`Locked`] resource for mutable access.
+/// Exported under the `internals` feature only.
 #[inline(always)]
 #[must_use]
 #[allow(dead_code)]

src/lib.rs

@@ -201,8 +201,6 @@ pub use api::{eval::eval, events::VarDefInfo, run::run};
 pub use ast::{FnAccess, AST};
 pub use engine::{Engine, OP_CONTAINS, OP_EQUALS};
 pub use eval::EvalContext;
-#[cfg(feature = "internals")]
-pub use func::native::{locked_read, locked_write};
 pub use func::{NativeCallContext, RegisterNativeFunction};
 pub use module::{FnNamespace, Module};
 pub use tokenizer::Position;
@@ -255,6 +253,9 @@ pub use func::Func;
 #[cfg(not(feature = "no_function"))]
 pub use ast::ScriptFnMetadata;
 
+#[cfg(not(feature = "no_function"))]
+pub use api::call_fn::CallFnOptions;
+
 /// Variable-sized array of [`Dynamic`] values.
 ///
 /// Not available under `no_index`.
@@ -342,7 +343,7 @@ pub use eval::{Caches, FnResolutionCache, FnResolutionCacheEntry, GlobalRuntimeS
 
 #[cfg(feature = "internals")]
 #[allow(deprecated)]
-pub use func::NativeCallContextStore;
+pub use func::{locked_read, locked_write, CallableFunction, NativeCallContextStore};
 
 #[cfg(feature = "internals")]
 #[cfg(feature = "metadata")]

src/module/resolvers/collection.rs

@@ -6,7 +6,7 @@ use crate::{
 use std::prelude::v1::*;
 use std::{ops::AddAssign, slice::Iter};
 
-/// [Module] resolution service that holds a collection of module resolvers,
+/// [Module][crate::Module] resolution service that holds a collection of module resolvers,
 /// to be searched in sequential order.
 ///
 /// # Example

src/module/resolvers/dummy.rs

@@ -2,7 +2,7 @@ use crate::{Engine, ModuleResolver, Position, RhaiResultOf, SharedModule, ERR};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
-/// Empty/disabled [module][Module] resolution service that acts as a dummy.
+/// Empty/disabled [module][crate::Module] resolution service that acts as a dummy.
 ///
 /// # Example
 ///

src/optimizer.rs

@@ -848,8 +848,8 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
         Stmt::Expr(expr) => {
             optimize_expr(expr, state, false);
 
-            if matches!(**expr, Expr::FnCall(..) | Expr::Stmt(..)) {
+            // Do not promote until the expression is fully optimized
-                state.set_dirty();
+            if !state.is_dirty() && matches!(**expr, Expr::FnCall(..) | Expr::Stmt(..)) {
                 *stmt = match *mem::take(expr) {
                     // func(...);
                     Expr::FnCall(x, pos) => Stmt::FnCall(x, pos),
@@ -859,6 +859,7 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
                     Expr::Stmt(x) => (*x).into(),
                     _ => unreachable!(),
                 };
+                state.set_dirty();
             }
         }
 
@@ -922,6 +923,22 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
             }
             // var.rhs
             (Expr::Variable(..), rhs) => optimize_expr(rhs, state, true),
+            // const.type_of()
+            (lhs, Expr::MethodCall(x, pos)) if lhs.is_constant() && x.name == KEYWORD_TYPE_OF && x.args.is_empty() => {
+                if let Some(value) = lhs.get_literal_value() {
+                    state.set_dirty();
+                    let typ = state.engine.map_type_name(value.type_name()).into();
+                    *expr = Expr::from_dynamic(typ, *pos);
+                }
+            }
+            // const.is_shared()
+            #[cfg(not(feature = "no_closure"))]
+            (lhs, Expr::MethodCall(x, pos)) if lhs.is_constant() && x.name == crate::engine::KEYWORD_IS_SHARED && x.args.is_empty() => {
+                if let Some(..) = lhs.get_literal_value() {
+                    state.set_dirty();
+                    *expr = Expr::from_dynamic(Dynamic::FALSE, *pos);
+                }
+            }
             // lhs.rhs
             (lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, true); }
         }

src/packages/iter_basic.rs

@@ -23,7 +23,7 @@ use rust_decimal::Decimal;
 #[inline(always)]
 fn std_add<T>(x: T, y: T) -> Option<T>
 where
-    T: Debug + Copy + PartialOrd + num_traits::CheckedAdd<Output = T>,
+    T: num_traits::CheckedAdd<Output = T>,
 {
     x.checked_add(&y)
 }
@@ -31,14 +31,14 @@ where
 #[allow(dead_code)]
 fn regular_add<T>(x: T, y: T) -> Option<T>
 where
-    T: Debug + Copy + PartialOrd + std::ops::Add<Output = T>,
+    T: std::ops::Add<Output = T>,
 {
     Some(x + y)
 }
 
 // Range iterator with step
 #[derive(Clone, Hash, Eq, PartialEq)]
-pub struct StepRange<T: Debug + Copy + PartialOrd> {
+pub struct StepRange<T> {
     pub from: T,
     pub to: T,
     pub step: T,
@@ -46,7 +46,7 @@ pub struct StepRange<T: Debug + Copy + PartialOrd> {
     pub dir: i8,
 }
 
-impl<T: Debug + Copy + PartialOrd> Debug for StepRange<T> {
+impl<T: Debug> Debug for StepRange<T> {
     #[cold]
     #[inline(never)]
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -58,7 +58,7 @@ impl<T: Debug + Copy + PartialOrd> Debug for StepRange<T> {
     }
 }
 
-impl<T: Debug + Copy + PartialOrd> StepRange<T> {
+impl<T: Copy + PartialOrd> StepRange<T> {
     pub fn new(from: T, to: T, step: T, add: fn(T, T) -> Option<T>) -> RhaiResultOf<Self> {
         let mut dir = 0;
 
@@ -95,7 +95,7 @@ impl<T: Debug + Copy + PartialOrd> StepRange<T> {
     }
 }
 
-impl<T: Debug + Copy + PartialOrd> Iterator for StepRange<T> {
+impl<T: Copy + PartialOrd> Iterator for StepRange<T> {
     type Item = T;
 
     fn next(&mut self) -> Option<T> {
@@ -118,7 +118,7 @@ impl<T: Debug + Copy + PartialOrd> Iterator for StepRange<T> {
     }
 }
 
-impl<T: Debug + Copy + PartialOrd> FusedIterator for StepRange<T> {}
+impl<T: Copy + PartialOrd> FusedIterator for StepRange<T> {}
 
 // Bit-field iterator with step
 #[derive(Debug, Clone, Hash, Eq, PartialEq)]

src/parser.rs

@@ -3818,7 +3818,7 @@ impl Engine {
         &self,
         input: &mut TokenStream,
         state: &mut ParseState,
-        process_settings: impl Fn(&mut ParseSettings),
+        process_settings: impl FnOnce(&mut ParseSettings),
         _optimization_level: OptimizationLevel,
     ) -> ParseResult<AST> {
         let mut functions = StraightHashMap::default();
@@ -3882,7 +3882,7 @@ impl Engine {
         &self,
         input: &mut TokenStream,
         state: &mut ParseState,
-        process_settings: impl Fn(&mut ParseSettings),
+        process_settings: impl FnOnce(&mut ParseSettings),
     ) -> ParseResult<(StmtBlockContainer, StaticVec<Shared<ScriptFnDef>>)> {
         let mut statements = StmtBlockContainer::new_const();
         let mut functions = StraightHashMap::default();

src/serde/deserialize.rs

@@ -127,20 +127,21 @@ impl<'de> Visitor<'de> for DynamicVisitor {
 
     #[inline(always)]
     fn visit_char<E: Error>(self, v: char) -> Result<Self::Value, E> {
-        self.visit_string(v.to_string())
+        Ok(v.into())
     }
     #[inline(always)]
     fn visit_str<E: Error>(self, v: &str) -> Result<Self::Value, E> {
         Ok(v.into())
     }
     #[inline(always)]
-    fn visit_borrowed_str<E: Error>(self, v: &str) -> Result<Self::Value, E> {
-        self.visit_str(v)
-    }
-    #[inline(always)]
     fn visit_string<E: Error>(self, v: String) -> Result<Self::Value, E> {
         Ok(v.into())
     }
+    #[cfg(not(feature = "no_index"))]
+    #[inline(always)]
+    fn visit_bytes<E: Error>(self, v: &[u8]) -> Result<Self::Value, E> {
+        Ok(Dynamic::from_blob(v.to_vec()))
+    }
 
     #[inline(always)]
     fn visit_unit<E: Error>(self) -> Result<Self::Value, E> {

src/serde/serialize.rs

@@ -20,7 +20,7 @@ impl Serialize for Dynamic {
             Union::Unit(..) => ser.serialize_unit(),
             Union::Bool(x, ..) => ser.serialize_bool(x),
             Union::Str(ref s, ..) => ser.serialize_str(s.as_str()),
-            Union::Char(c, ..) => ser.serialize_str(&c.to_string()),
+            Union::Char(c, ..) => ser.serialize_char(c),
 
             #[cfg(not(feature = "only_i32"))]
             Union::Int(x, ..) => ser.serialize_i64(x),
@@ -58,7 +58,7 @@ impl Serialize for Dynamic {
             #[cfg(not(feature = "no_index"))]
             Union::Array(ref a, ..) => (**a).serialize(ser),
             #[cfg(not(feature = "no_index"))]
-            Union::Blob(ref a, ..) => (**a).serialize(ser),
+            Union::Blob(ref a, ..) => ser.serialize_bytes(&**a),
             #[cfg(not(feature = "no_object"))]
             Union::Map(ref m, ..) => {
                 let mut map = ser.serialize_map(Some(m.len()))?;

src/types/dynamic.rs

@@ -1181,42 +1181,105 @@ impl Dynamic {
     /// ```
     #[inline]
     #[must_use]
-    pub fn try_cast<T: Any>(self) -> Option<T> {
+    pub fn try_cast<T: Any>(mut self) -> Option<T> {
         // Coded this way in order to maximally leverage potentials for dead-code removal.
 
         #[cfg(not(feature = "no_closure"))]
-        if let Union::Shared(..) = self.0 {
+        self.flatten_in_place();
-            return self.flatten().try_cast::<T>();
+
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return Some(reify!(self => T));
+        }
+        if TypeId::of::<T>() == TypeId::of::<()>() {
+            return match self.0 {
+                Union::Unit(..) => Some(reify!(() => T)),
+                _ => None,
+            };
+        }
+        if TypeId::of::<T>() == TypeId::of::<INT>() {
+            return match self.0 {
+                Union::Int(n, ..) => Some(reify!(n => T)),
+                _ => None,
+            };
+        }
+        #[cfg(not(feature = "no_float"))]
+        if TypeId::of::<T>() == TypeId::of::<crate::FLOAT>() {
+            return match self.0 {
+                Union::Float(v, ..) => Some(reify!(*v => T)),
+                _ => None,
+            };
+        }
+        #[cfg(feature = "decimal")]
+        if TypeId::of::<T>() == TypeId::of::<rust_decimal::Decimal>() {
+            return match self.0 {
+                Union::Decimal(v, ..) => Some(reify!(*v => T)),
+                _ => None,
+            };
+        }
+        if TypeId::of::<T>() == TypeId::of::<bool>() {
+            return match self.0 {
+                Union::Bool(b, ..) => Some(reify!(b => T)),
+                _ => None,
+            };
+        }
+        if TypeId::of::<T>() == TypeId::of::<ImmutableString>() {
+            return match self.0 {
+                Union::Str(s, ..) => Some(reify!(s => T)),
+                _ => None,
+            };
+        }
+        if TypeId::of::<T>() == TypeId::of::<String>() {
+            return match self.0 {
+                Union::Str(s, ..) => Some(reify!(s.to_string() => T)),
+                _ => None,
+            };
+        }
+        if TypeId::of::<T>() == TypeId::of::<char>() {
+            return match self.0 {
+                Union::Char(c, ..) => Some(reify!(c => T)),
+                _ => None,
+            };
+        }
+        #[cfg(not(feature = "no_index"))]
+        if TypeId::of::<T>() == TypeId::of::<crate::Array>() {
+            return match self.0 {
+                Union::Array(a, ..) => Some(reify!(*a => T)),
+                _ => None,
+            };
+        }
+        #[cfg(not(feature = "no_index"))]
+        if TypeId::of::<T>() == TypeId::of::<crate::Blob>() {
+            return match self.0 {
+                Union::Blob(b, ..) => Some(reify!(*b => T)),
+                _ => None,
+            };
+        }
+        #[cfg(not(feature = "no_object"))]
+        if TypeId::of::<T>() == TypeId::of::<crate::Map>() {
+            return match self.0 {
+                Union::Map(m, ..) => Some(reify!(*m => T)),
+                _ => None,
+            };
+        }
+        if TypeId::of::<T>() == TypeId::of::<FnPtr>() {
+            return match self.0 {
+                Union::FnPtr(f, ..) => Some(reify!(*f => T)),
+                _ => None,
+            };
+        }
+        #[cfg(not(feature = "no_time"))]
+        if TypeId::of::<T>() == TypeId::of::<Instant>() {
+            return match self.0 {
+                Union::TimeStamp(t, ..) => Some(reify!(*t => T)),
+                _ => None,
+            };
         }
 
-        reify!(self, |v: T| return Some(v));
-
         match self.0 {
-            Union::Null => unreachable!(),
-
-            Union::Int(v, ..) => reify!(v => Option<T>),
-            #[cfg(not(feature = "no_float"))]
-            Union::Float(v, ..) => reify!(*v => Option<T>),
-            #[cfg(feature = "decimal")]
-            Union::Decimal(v, ..) => reify!(*v => Option<T>),
-            Union::Bool(v, ..) => reify!(v => Option<T>),
-            Union::Str(v, ..) => {
-                reify!(v, |v: T| Some(v), || reify!(v.to_string() => Option<T>))
-            }
-            Union::Char(v, ..) => reify!(v => Option<T>),
-            #[cfg(not(feature = "no_index"))]
-            Union::Array(v, ..) => reify!(*v => Option<T>),
-            #[cfg(not(feature = "no_index"))]
-            Union::Blob(v, ..) => reify!(*v => Option<T>),
-            #[cfg(not(feature = "no_object"))]
-            Union::Map(v, ..) => reify!(*v => Option<T>),
-            Union::FnPtr(v, ..) => reify!(*v => Option<T>),
-            #[cfg(not(feature = "no_time"))]
-            Union::TimeStamp(v, ..) => reify!(*v => Option<T>),
-            Union::Unit(v, ..) => reify!(v => Option<T>),
             Union::Variant(v, ..) => (*v).as_boxed_any().downcast().ok().map(|x| *x),
             #[cfg(not(feature = "no_closure"))]
             Union::Shared(..) => unreachable!("Union::Shared case should be already handled"),
+            _ => None,
         }
     }
     /// Convert the [`Dynamic`] value into a specific type.
@@ -1245,6 +1308,11 @@ impl Dynamic {
     #[inline]
     #[must_use]
     pub fn cast<T: Any + Clone>(self) -> T {
+        // Bail out early if the return type needs no cast
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return reify!(self => T);
+        }
+
         #[cfg(not(feature = "no_closure"))]
         let self_type_name = if self.is_shared() {
             // Avoid panics/deadlocks with shared values

src/types/error.rs

@@ -198,7 +198,7 @@ impl fmt::Display for EvalAltResult {
                 if s.starts_with(crate::engine::FN_SET) =>
             {
                 let prop = &s[crate::engine::FN_SET.len()..];
-                write!(f, "Cannot modify property {prop} of constant")?
+                write!(f, "Cannot modify property '{prop}' of a constant")?
             }
             #[cfg(not(feature = "no_index"))]
             Self::ErrorNonPureMethodCallOnConstant(s, ..) if s == crate::engine::FN_IDX_GET => {
@@ -209,10 +209,10 @@ impl fmt::Display for EvalAltResult {
             }
             #[cfg(not(feature = "no_index"))]
             Self::ErrorNonPureMethodCallOnConstant(s, ..) if s == crate::engine::FN_IDX_SET => {
-                write!(f, "Cannot assign to indexer of constant")?
+                write!(f, "Cannot assign to the indexer of a constant")?
             }
             Self::ErrorNonPureMethodCallOnConstant(s, ..) => {
-                write!(f, "Non-pure method {s} cannot be called on constant")?
+                write!(f, "Non-pure method '{s}' cannot be called on a constant")?
             }
 
             Self::ErrorAssignmentToConstant(s, ..) => write!(f, "Cannot modify constant {s}")?,
@@ -230,8 +230,8 @@ impl fmt::Display for EvalAltResult {
             Self::ErrorArithmetic(s, ..) if s.is_empty() => f.write_str("Arithmetic error")?,
             Self::ErrorArithmetic(s, ..) => f.write_str(s)?,
 
-            Self::LoopBreak(true, ..) => f.write_str("'break' not inside a loop")?,
+            Self::LoopBreak(true, ..) => f.write_str("'break' must be inside a loop")?,
-            Self::LoopBreak(false, ..) => f.write_str("'continue' not inside a loop")?,
+            Self::LoopBreak(false, ..) => f.write_str("'continue' must be inside a loop")?,
 
             Self::Return(..) => f.write_str("NOT AN ERROR - function returns value")?,
 

src/types/fn_ptr.rs

@@ -4,13 +4,13 @@ use crate::eval::GlobalRuntimeState;
 use crate::tokenizer::is_valid_function_name;
 use crate::types::dynamic::Variant;
 use crate::{
-    Dynamic, Engine, FuncArgs, ImmutableString, NativeCallContext, Position, RhaiError, RhaiResult,
+    reify, Dynamic, Engine, FuncArgs, ImmutableString, NativeCallContext, Position, RhaiError,
-    RhaiResultOf, StaticVec, AST, ERR,
+    RhaiResult, RhaiResultOf, StaticVec, AST, ERR,
 };
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
-    any::type_name,
+    any::{type_name, TypeId},
     convert::{TryFrom, TryInto},
     fmt, mem,
 };
@@ -160,6 +160,11 @@ impl FnPtr {
 
         let result = self.call_raw(&ctx, None, arg_values)?;
 
+        // Bail out early if the return type needs no cast
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return Ok(reify!(result => T));
+        }
+
         let typ = engine.map_type_name(result.type_name());
 
         result.try_cast().ok_or_else(|| {
@@ -184,6 +189,11 @@ impl FnPtr {
 
         let result = self.call_raw(context, None, arg_values)?;
 
+        // Bail out early if the return type needs no cast
+        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+            return Ok(reify!(result => T));
+        }
+
         let typ = context.engine().map_type_name(result.type_name());
 
         result.try_cast().ok_or_else(|| {

src/types/interner.rs

@@ -80,7 +80,7 @@ impl StringsInterner<'_> {
     pub fn get_with_mapper<S: AsRef<str>>(
         &mut self,
         id: &str,
-        mapper: impl Fn(S) -> ImmutableString,
+        mapper: impl FnOnce(S) -> ImmutableString,
         text: S,
     ) -> ImmutableString {
         let key = text.as_ref();

src/types/scope.rs

@@ -445,7 +445,8 @@ impl Scope<'_> {
             .rev()
             .enumerate()
             .find(|(.., key)| &name == key)
-            .and_then(|(index, ..)| self.values[len - 1 - index].flatten_clone().try_cast())
+            .map(|(index, ..)| self.values[len - 1 - index].flatten_clone())
+            .and_then(Dynamic::try_cast)
     }
     /// Check if the named entry in the [`Scope`] is constant.
     ///

tests/call_fn.rs

@@ -1,5 +1,5 @@
 #![cfg(not(feature = "no_function"))]
-use rhai::{Dynamic, Engine, EvalAltResult, FnPtr, Func, FuncArgs, Scope, AST, INT};
+use rhai::{CallFnOptions, Dynamic, Engine, EvalAltResult, FnPtr, Func, FuncArgs, Scope, AST, INT};
 use std::any::TypeId;
 
 #[test]
@@ -50,11 +50,10 @@ fn test_call_fn() -> Result<(), Box<EvalAltResult>> {
 
     assert!(!scope.contains("bar"));
 
-    let args = [(2 as INT).into()];
+    let options = CallFnOptions::new().eval_ast(false).rewind_scope(false);
-    let r = engine
+
-        .call_fn_raw(&mut scope, &ast, false, false, "define_var", None, args)?
+    let r =
-        .as_int()
+        engine.call_fn_with_options::<INT>(options, &mut scope, &ast, "define_var", (2 as INT,))?;
-        .unwrap();
     assert_eq!(r, 42);
 
     assert_eq!(
@@ -87,9 +86,13 @@ fn test_call_fn_scope() -> Result<(), Box<EvalAltResult>> {
 
     for _ in 0..50 {
         assert_eq!(
-            engine
+            engine.call_fn_with_options::<INT>(
-                .call_fn_raw(&mut scope, &ast, true, false, "foo", None, [Dynamic::THREE])?
+                CallFnOptions::new().rewind_scope(false),
-                .as_int()?,
+                &mut scope,
+                &ast,
+                "foo",
+                [Dynamic::THREE],
+            )?,
             168
         );
     }

tests/serde.rs

@@ -798,6 +798,7 @@ fn test_serde_optional() -> Result<(), Box<EvalAltResult>> {
 
 #[test]
 #[cfg(not(feature = "no_index"))]
+#[cfg(not(feature = "no_object"))]
 fn test_serde_blob() -> Result<(), Box<EvalAltResult>> {
     let engine = Engine::new();
 
@@ -805,13 +806,16 @@ fn test_serde_blob() -> Result<(), Box<EvalAltResult>> {
         "
             let x = blob(10);
             for i in 0..10 { x[i] = i; }
-            x
+            #{ x: x }
         ",
     )?;
 
-    let r = from_dynamic::<serde_bytes::ByteBuf>(&r)?;
+    let data = format!("{r:?}");
 
-    assert_eq!(r.to_vec(), vec![0_u8, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
+    let encoded = rmp_serde::to_vec(&r).unwrap();
+    let decoded: Dynamic = rmp_serde::from_slice(&encoded).unwrap();
+
+    assert_eq!(format!("{decoded:?}"), data);
 
     Ok(())
 }