From 3a7d384dc8d28d7c04bb0d04debfda7dcc490ddf Mon Sep 17 00:00:00 2001
From: Ingvar Stepanyan <me@rreverser.com>
Date: Tue, 16 Apr 2019 20:31:25 +0100
Subject: [PATCH] Generate bindings for indexed struct properties

This allows to export fields of tuple-like structs as indexed JS properties.
---
 crates/backend/src/ast.rs          |  2 +-
 crates/backend/src/encode.rs       |  5 ++-
 crates/macro-support/src/parser.rs | 63 ++++++++++++++----------------
 tests/wasm/classes.js              |  1 +
 tests/wasm/classes.rs              | 11 ++++++
 5 files changed, 47 insertions(+), 35 deletions(-)

diff --git a/crates/backend/src/ast.rs b/crates/backend/src/ast.rs
index aeb56ccb..c54a27be 100644
--- a/crates/backend/src/ast.rs
+++ b/crates/backend/src/ast.rs
@@ -227,7 +227,7 @@ pub struct Struct {
 #[cfg_attr(feature = "extra-traits", derive(Debug, PartialEq, Eq))]
 #[derive(Clone)]
 pub struct StructField {
-    pub name: Ident,
+    pub name: syn::Member,
     pub struct_name: Ident,
     pub readonly: bool,
     pub ty: syn::Type,
diff --git a/crates/backend/src/encode.rs b/crates/backend/src/encode.rs
index b0cc9cb6..ae8d4cd3 100644
--- a/crates/backend/src/encode.rs
+++ b/crates/backend/src/encode.rs
@@ -332,7 +332,10 @@ fn shared_struct<'a>(s: &'a ast::Struct, intern: &'a Interner) -> Struct<'a> {
 
 fn shared_struct_field<'a>(s: &'a ast::StructField, intern: &'a Interner) -> StructField<'a> {
     StructField {
-        name: intern.intern(&s.name),
+        name: match &s.name {
+            syn::Member::Named(ident) => intern.intern(ident),
+            syn::Member::Unnamed(index) => intern.intern_str(&index.index.to_string()),
+        },
         readonly: s.readonly,
         comments: s.comments.iter().map(|s| &**s).collect(),
     }
diff --git a/crates/macro-support/src/parser.rs b/crates/macro-support/src/parser.rs
index 998b6a8f..165e76f4 100644
--- a/crates/macro-support/src/parser.rs
+++ b/crates/macro-support/src/parser.rs
@@ -309,40 +309,37 @@ impl<'a> ConvertToAst<BindgenAttrs> for &'a mut syn::ItemStruct {
             .js_name()
             .map(|s| s.0.to_string())
             .unwrap_or(self.ident.to_string());
-        if let syn::Fields::Named(names) = &mut self.fields {
-            for field in names.named.iter_mut() {
-                match field.vis {
-                    syn::Visibility::Public(..) => {}
-                    _ => continue,
-                }
-                let name = match &field.ident {
-                    Some(n) => n,
-                    None => continue,
-                };
-
-                let attrs = BindgenAttrs::find(&mut field.attrs)?;
-                assert_not_variadic(&attrs)?;
-                if attrs.skip().is_some() {
-                    attrs.check_used()?;
-                    continue;
-                }
-
-                let comments = extract_doc_comments(&field.attrs);
-                let name_str = name.to_string();
-                let getter = shared::struct_field_get(&js_name, &name_str);
-                let setter = shared::struct_field_set(&js_name, &name_str);
-
-                fields.push(ast::StructField {
-                    name: name.clone(),
-                    struct_name: self.ident.clone(),
-                    readonly: attrs.readonly().is_some(),
-                    ty: field.ty.clone(),
-                    getter: Ident::new(&getter, Span::call_site()),
-                    setter: Ident::new(&setter, Span::call_site()),
-                    comments,
-                });
-                attrs.check_used()?;
+        for (i, field) in self.fields.iter_mut().enumerate() {
+            match field.vis {
+                syn::Visibility::Public(..) => {}
+                _ => continue,
             }
+            let (name_str, member) = match &field.ident {
+                Some(ident) => (ident.to_string(), syn::Member::Named(ident.clone())),
+                None => (i.to_string(), syn::Member::Unnamed(i.into())),
+            };
+
+            let attrs = BindgenAttrs::find(&mut field.attrs)?;
+            assert_not_variadic(&attrs)?;
+            if attrs.skip().is_some() {
+                attrs.check_used()?;
+                continue;
+            }
+
+            let comments = extract_doc_comments(&field.attrs);
+            let getter = shared::struct_field_get(&js_name, &name_str);
+            let setter = shared::struct_field_set(&js_name, &name_str);
+
+            fields.push(ast::StructField {
+                name: member,
+                struct_name: self.ident.clone(),
+                readonly: attrs.readonly().is_some(),
+                ty: field.ty.clone(),
+                getter: Ident::new(&getter, Span::call_site()),
+                setter: Ident::new(&setter, Span::call_site()),
+                comments,
+            });
+            attrs.check_used()?;
         }
         let comments: Vec<String> = extract_doc_comments(&self.attrs);
         attrs.check_used()?;
diff --git a/tests/wasm/classes.js b/tests/wasm/classes.js
index 995e87dd..86de4727 100644
--- a/tests/wasm/classes.js
+++ b/tests/wasm/classes.js
@@ -137,6 +137,7 @@ exports.js_js_rename = () => {
 
 exports.js_access_fields = () => {
     assert.ok((new wasm.AccessFieldFoo()).bar instanceof wasm.AccessFieldBar);
+    assert.ok((new wasm.AccessField0())[0] instanceof wasm.AccessFieldBar);
 };
 
 exports.js_renamed_export = () => {
diff --git a/tests/wasm/classes.rs b/tests/wasm/classes.rs
index be167058..ee904c05 100644
--- a/tests/wasm/classes.rs
+++ b/tests/wasm/classes.rs
@@ -369,6 +369,9 @@ pub struct AccessFieldFoo {
     pub bar: AccessFieldBar,
 }
 
+#[wasm_bindgen]
+pub struct AccessField0(pub AccessFieldBar);
+
 #[wasm_bindgen]
 #[derive(Copy, Clone)]
 pub struct AccessFieldBar {
@@ -385,6 +388,14 @@ impl AccessFieldFoo {
     }
 }
 
+#[wasm_bindgen]
+impl AccessField0 {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> AccessField0 {
+        AccessField0(AccessFieldBar { _value: 2 })
+    }
+}
+
 #[wasm_bindgen_test]
 fn access_fields() {
     js_access_fields();