diff --git a/codegen/src/lib.rs b/codegen/src/lib.rs
index 6ece57c61..028dc252c 100644
--- a/codegen/src/lib.rs
+++ b/codegen/src/lib.rs
@@ -31,61 +31,6 @@
 //! #   Ok(())
 //! # }
 //! ```
-//!
-//! # Register a Rust Function with a Rhai `Module`
-//!
-//! ```
-//! use rhai::{EvalAltResult, FLOAT, Module};
-//! use rhai::plugin::*;
-//! use rhai::module_resolvers::*;
-//!
-//! #[export_fn]
-//! fn distance_function(x1: FLOAT, y1: FLOAT, x2: FLOAT, y2: FLOAT) -> FLOAT {
-//!     ((y2 - y1).abs().powf(2.0) + (x2 -x1).abs().powf(2.0)).sqrt()
-//! }
-//!
-//! # fn main() -> Result<(), Box<EvalAltResult>> {
-//! let mut engine = Engine::new();
-//! engine.register_fn("get_mystic_number", || 42.0 as FLOAT);
-//! let mut m = Module::new();
-//! set_exported_fn!(m, "euclidean_distance", distance_function);
-//! let mut r = StaticModuleResolver::new();
-//! r.insert("Math::Advanced", m);
-//! engine.set_module_resolver(r);
-//!
-//! assert_eq!(engine.eval::<FLOAT>(
-//!     r#"
-//!         import "Math::Advanced" as math;
-//!         math::euclidean_distance(0.0, 1.0, 0.0, get_mystic_number())
-//!     "#)?, 41.0);
-//! # Ok(())
-//! # }
-//! ```
-//!
-//! # Register a Plugin Function with an `Engine`
-//!
-//! ```
-//! use rhai::{EvalAltResult, FLOAT, Module};
-//! use rhai::plugin::*;
-//! use rhai::module_resolvers::*;
-//!
-//! #[export_fn]
-//! pub fn distance_function(x1: FLOAT, y1: FLOAT, x2: FLOAT, y2: FLOAT) -> FLOAT {
-//!     ((y2 - y1).abs().powf(2.0) + (x2 -x1).abs().powf(2.0)).sqrt()
-//! }
-//!
-//! # fn main() -> Result<(), Box<EvalAltResult>> {
-//! let mut engine = Engine::new();
-//! engine.register_fn("get_mystic_number", || { 42 as FLOAT });
-//! register_exported_fn!(engine, "euclidean_distance", distance_function);
-//!
-//! assert_eq!(engine.eval::<FLOAT>(
-//!         "euclidean_distance(0.0, 1.0, 0.0, get_mystic_number())"
-//!     )?, 41.0);
-//! # Ok(())
-//! # }
-//! ```
-//!
 
 use quote::quote;
 use syn::{parse_macro_input, spanned::Spanned, DeriveInput};
@@ -100,61 +45,6 @@ mod rhai_module;
 #[cfg(test)]
 mod test;
 
-/// Attribute, when put on a Rust function, turns it into a _plugin function_.
-///
-/// # Usage
-///
-/// ```
-/// # use rhai::{Engine, EvalAltResult};
-/// use rhai::plugin::*;
-///
-/// #[export_fn]
-/// fn my_plugin_function(x: i64) -> i64 {
-///     x * 2
-/// }
-///
-/// # fn main() -> Result<(), Box<EvalAltResult>> {
-/// let mut engine = Engine::new();
-///
-/// register_exported_fn!(engine, "func", my_plugin_function);
-///
-/// assert_eq!(engine.eval::<i64>("func(21)")?, 42);
-/// # Ok(())
-/// # }
-/// ```
-#[proc_macro_attribute]
-pub fn export_fn(
-    args: proc_macro::TokenStream,
-    input: proc_macro::TokenStream,
-) -> proc_macro::TokenStream {
-    let mut output = quote! {
-        #[allow(clippy::needless_pass_by_value)]
-    };
-    output.extend(proc_macro2::TokenStream::from(input.clone()));
-
-    let parsed_params = match crate::attrs::outer_item_attributes(args.into(), "export_fn") {
-        Ok(args) => args,
-        Err(err) => return err.to_compile_error().into(),
-    };
-    let mut function_def = parse_macro_input!(input as function::ExportedFn);
-
-    if !function_def.cfg_attrs().is_empty() {
-        return syn::Error::new(
-            function_def.cfg_attrs()[0].span(),
-            "`cfg` attributes are not allowed for `export_fn`",
-        )
-        .to_compile_error()
-        .into();
-    }
-
-    if let Err(e) = function_def.set_params(parsed_params) {
-        return e.to_compile_error().into();
-    }
-
-    output.extend(function_def.generate());
-    proc_macro::TokenStream::from(output)
-}
-
 /// Attribute, when put on a Rust module, turns it into a _plugin module_.
 ///
 /// # Usage
@@ -279,6 +169,47 @@ pub fn combine_with_exported_module(args: proc_macro::TokenStream) -> proc_macro
     }
 }
 
+/// Attribute, when put on a Rust function, turns it into a _plugin function_.
+///
+/// # Deprecated
+///
+/// This macro is deprecated as it performs no additional value.
+///
+/// This method will be removed in the next major version.
+#[deprecated(since = "1.18.0")]
+#[proc_macro_attribute]
+pub fn export_fn(
+    args: proc_macro::TokenStream,
+    input: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+    let mut output = quote! {
+        #[allow(clippy::needless_pass_by_value)]
+    };
+    output.extend(proc_macro2::TokenStream::from(input.clone()));
+
+    let parsed_params = match crate::attrs::outer_item_attributes(args.into(), "export_fn") {
+        Ok(args) => args,
+        Err(err) => return err.to_compile_error().into(),
+    };
+    let mut function_def = parse_macro_input!(input as function::ExportedFn);
+
+    if !function_def.cfg_attrs().is_empty() {
+        return syn::Error::new(
+            function_def.cfg_attrs()[0].span(),
+            "`cfg` attributes are not allowed for `export_fn`",
+        )
+        .to_compile_error()
+        .into();
+    }
+
+    if let Err(e) = function_def.set_params(parsed_params) {
+        return e.to_compile_error().into();
+    }
+
+    output.extend(function_def.generate());
+    proc_macro::TokenStream::from(output)
+}
+
 /// Macro to register a _plugin function_ (defined via [`#[export_fn]`][macro@export_fn]) into an `Engine`.
 ///
 /// # Deprecated