Add ability to rename enums (js_name = new_name) (#2071)

* Add ability to rename enums (js_name = new_name)

* Add a test

crates/backend/src/ast.rs

@@ -251,7 +251,8 @@ pub struct StructField {
 #[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 #[derive(Clone)]
 pub struct Enum {
-    pub name: Ident,
+    pub rust_name: Ident,
+    pub js_name: String,
     pub variants: Vec<Variant>,
     pub comments: Vec<String>,
     pub hole: u32,

crates/backend/src/codegen.rs

@@ -1113,7 +1113,7 @@ impl<'a> ToTokens for DescribeImport<'a> {
 
 impl ToTokens for ast::Enum {
     fn to_tokens(&self, into: &mut TokenStream) {
-        let enum_name = &self.name;
+        let enum_name = &self.rust_name;
         let hole = &self.hole;
         let cast_clauses = self.variants.iter().map(|variant| {
             let variant_name = &variant.name;

crates/backend/src/encode.rs

@@ -212,7 +212,7 @@ fn shared_function<'a>(func: &'a ast::Function, _intern: &'a Interner) -> Functi
 
 fn shared_enum<'a>(e: &'a ast::Enum, intern: &'a Interner) -> Enum<'a> {
     Enum {
-        name: intern.intern(&e.name),
+        name: &e.js_name,
         variants: e
             .variants
             .iter()

crates/macro-support/src/parser.rs

@@ -1058,7 +1058,6 @@ impl<'a> MacroParse<(&'a mut TokenStream, BindgenAttrs)> for syn::ItemEnum {
             bail_span!(self, "cannot export empty enums to JS");
         }
         let generate_typescript = opts.skip_typescript().is_none();
-        opts.check_used()?;
 
         // Check if the first value is a string literal
         match self.variants[0].discriminant {
@@ -1069,10 +1068,16 @@ impl<'a> MacroParse<(&'a mut TokenStream, BindgenAttrs)> for syn::ItemEnum {
                     lit: syn::Lit::Str(_),
                 }),
             )) => {
+                opts.check_used()?;
                 return import_enum(self, program);
             }
             _ => {}
         }
+        let js_name = opts
+            .js_name()
+            .map(|s| s.0)
+            .map_or_else(|| self.ident.to_string(), |s| s.to_string());
+        opts.check_used()?;
 
         let has_discriminant = self.variants[0].discriminant.is_some();
 
@@ -1155,7 +1160,8 @@ impl<'a> MacroParse<(&'a mut TokenStream, BindgenAttrs)> for syn::ItemEnum {
         self.to_tokens(tokens);
 
         program.enums.push(ast::Enum {
-            name: self.ident,
+            rust_name: self.ident,
+            js_name,
             variants,
             comments,
             hole,

tests/wasm/enums.js

@@ -28,3 +28,7 @@ exports.js_expect_enum = (a, b) => {
 exports.js_expect_enum_none = a => {
   assert.strictEqual(a, undefined);
 };
+
+exports.js_renamed_enum = b => {
+  assert.strictEqual(wasm.JsRenamedEnum.B, b);
+};

tests/wasm/enums.rs

@@ -9,6 +9,7 @@ extern "C" {
     fn js_handle_optional_enums(x: Option<Color>) -> Option<Color>;
     fn js_expect_enum(x: Color, y: Option<Color>);
     fn js_expect_enum_none(x: Option<Color>);
+    fn js_renamed_enum(b: RenamedEnum);
 }
 
 #[wasm_bindgen]
@@ -30,6 +31,13 @@ pub mod inner {
     }
 }
 
+#[wasm_bindgen(js_name = JsRenamedEnum)]
+#[derive(Copy, Clone)]
+pub enum RenamedEnum {
+    A = 10,
+    B = 20,
+}
+
 #[wasm_bindgen]
 pub fn enum_cycle(color: Color) -> Color {
     match color {
@@ -82,3 +90,8 @@ fn test_optional_enum_values() {
     js_expect_enum(Red, Some(Red));
     js_expect_enum_none(None);
 }
+
+#[wasm_bindgen_test]
+fn test_renamed_enum() {
+    js_renamed_enum(RenamedEnum::B);
+}