mlua_derive: Strip raw-identifier prefix from Lua names

Author: khvzak

mlua_derive/src/from_lua.rs

@@ -1,13 +1,14 @@
 use proc_macro::TokenStream;
 use quote::quote;
+use syn::ext::IdentExt;
 use syn::{DeriveInput, parse_macro_input, parse_quote};
 
 pub fn from_lua(input: TokenStream) -> TokenStream {
     let DeriveInput {
         ident, mut generics, ..
     } = parse_macro_input!(input as DeriveInput);
 
-    let ident_str = ident.to_string();
+    let ident_str = ident.unraw().to_string();
     generics
         .make_where_clause()
         .predicates

mlua_derive/src/userdata/attr.rs

@@ -1,4 +1,5 @@
 use proc_macro2::Span;
+use syn::ext::IdentExt;
 use syn::meta::ParseNestedMeta;
 use syn::{Ident, LitStr, Result};
 
@@ -63,7 +64,7 @@ impl LuaAttr {
 
     /// Returns the effective Lua name.
     pub(crate) fn name(&self, ident: &Ident) -> String {
-        self.name.clone().unwrap_or_else(|| ident.to_string())
+        self.name.clone().unwrap_or_else(|| ident.unraw().to_string())
     }
 
     /// Returns the span to use for error reporting.
@@ -79,7 +80,7 @@ impl LuaAttr {
         if let Some(ref name) = self.name {
             return Ok(name.clone());
         }
-        let fn_name = fn_ident.to_string();
+        let fn_name = fn_ident.unraw().to_string();
         if fn_name.starts_with("__") {
             return Ok(fn_name);
         }

mlua_derive/src/userdata/mod.rs

@@ -3,6 +3,7 @@ pub(crate) mod userdata_impl;
 
 use proc_macro::TokenStream;
 use quote::{format_ident, quote};
+use syn::ext::IdentExt;
 use syn::spanned::Spanned;
 use syn::{Attribute, Data, DeriveInput, Error, Fields, FieldsNamed, Meta, parse_macro_input};
 
@@ -103,7 +104,7 @@ pub fn userdata_type(item: TokenStream) -> TokenStream {
                 continue;
             }
 
-            let lua_name = lua_attr.name.unwrap_or_else(|| field_name.to_string());
+            let lua_name = lua_attr.name.unwrap_or_else(|| field_name.unraw().to_string());
 
             // Assume get/set by default (unless explicitly specified)
             let (has_get, has_set) = if lua_attr.get || lua_attr.set {

tests/userdata_macro.rs

@@ -474,13 +474,14 @@ fn test_static_metamethods() {
 #[derive(Clone, Debug, UserData)]
 struct Hygiene {
     value: i32,
+    r#type: i32,
 }
 
 #[mlua::userdata_impl]
 impl Hygiene {
     #[lua(infallible)]
     fn new(value: i32) -> Self {
-        Hygiene { value }
+        Hygiene { value, r#type: 7 }
     }
 
     // `this` must not clash with the generated receiver binding.
@@ -494,6 +495,11 @@ impl Hygiene {
     fn add_lua(&self, lua: i32) -> i32 {
         self.value + lua
     }
+
+    #[lua(infallible)]
+    fn r#double_type(&self) -> i32 {
+        self.r#type * 2
+    }
 }
 
 #[test]
@@ -505,8 +511,17 @@ fn test_param_name_hygiene() {
     lua.load(
         r#"
         local h = Hygiene.new(10)
+
+        -- reserved parameter names must not clash with generated bindings
         assert(h:add_this(5) == 15, "add_this should be 10 + 5 = 15")
         assert(h:add_lua(3) == 13, "add_lua should be 10 + 3 = 13")
+
+        -- the `r#` prefix must not leak into Lua names
+        assert(h.type == 7, "field r#type should be exposed as 'type'")
+        h.type = 10
+        assert(h.type == 10, "field r#type setter should update via 'type'")
+        assert(h:double_type() == 20, "method r#double_type should be callable as 'double_type'")
+        assert(h["r#type"] == nil, "the raw prefix must not leak into the Lua name")
     "#,
     )
     .exec()