#[derive(CloneRef)] also works on types with type-level bounds. (https://github.com/enso-org/ide/pull/323)

Original commit: b9f9c37d96

gui/src/rust/lib/macro-utils/src/lib.rs

@@ -7,13 +7,13 @@ pub use enso_prelude as prelude;
 
 use crate::prelude::*;
 
+use proc_macro2::TokenStream;
+use proc_macro2::TokenTree;
 use quote::quote;
 use syn;
 use syn::visit::Visit;
-use proc_macro2::TokenStream;
+use syn::WhereClause;
-use proc_macro2::TokenTree;
+use syn::WherePredicate;
-
-
 
 // =========================
 // === Token Stream Utils ===
@@ -240,6 +240,18 @@ pub fn variant_depends_on
 
 
 
+// ===================
+// === WhereClause ===
+// ===================
+
+/// Creates a new where clause from provided sequence of where predicates.
+pub fn new_where_clause(predicates:impl IntoIterator<Item=WherePredicate>) -> WhereClause {
+    let predicates = syn::punctuated::Punctuated::from_iter(predicates);
+    WhereClause {where_token:default(),predicates}
+}
+
+
+
 // =============
 // === Tests ===
 // =============

gui/src/rust/lib/shapely/impl/tests/derive_clone_ref.rs

@@ -36,3 +36,21 @@ struct StructUnnamedBound<T>(T);
 #[derive(CloneRef,Clone)]
 #[clone_ref(bound="T:CloneRef,U:CloneRef")]
 struct StructUnnamedBoundTwoPatams<T,U>(T,U);
+
+#[derive(Clone,CloneRef)]
+#[clone_ref(bound="T:Clone+Display")]
+struct StructBoundGeneric<T:Display>(Rc<T>);
+
+#[derive(CloneRef,Derivative)]
+#[derivative(Clone(bound=""))]
+// Note: CloneRef "knows" about `Display` bound.
+struct StructGenericLifetime<'t>(Rc<&'t String>);
+
+#[derive(CloneRef,Derivative)]
+#[derivative(Clone(bound=""))]
+struct StructWhereClause<T>(Rc<T>) where T:Debug;
+
+#[derive(CloneRef,Clone)]
+#[clone_ref(bound="T:CloneRef")]
+// Here derive macro must correctly merge user-provided bound, generics list bound and where clause.
+struct StructVariousBounds<T:Display>(T) where T:Debug;

gui/src/rust/lib/shapely/macros/src/derive_clone_ref.rs

@@ -5,11 +5,12 @@ use macro_utils::identifier_sequence;
 use macro_utils::index_sequence;
 use macro_utils::path_matching_ident;
 use syn::Attribute;
-use syn::Ident;
+use syn::DeriveInput;
 use syn::Data;
 use syn::DataEnum;
 use syn::DataStruct;
 use syn::Fields;
+use syn::Ident;
 use syn::Lit;
 use syn::Meta;
 use syn::MetaNameValue;
@@ -19,6 +20,7 @@ use syn::WhereClause;
 use syn::WherePredicate;
 
 
+
 // ==============
 // === Consts ===
 // ==============
@@ -184,8 +186,7 @@ pub fn clone_ref_bounds(attr:&Attribute) -> Option<Vec<WherePredicate>> {
 /// Derives `CloneRef` implementation, refer to `crate::derive_clone_ref` for details.
 pub fn derive
 (input:proc_macro::TokenStream) -> proc_macro::TokenStream {
-    let decl   = syn::parse_macro_input!(input as syn::DeriveInput);
+    let decl   = syn::parse_macro_input!(input as DeriveInput);
-    let params = &decl.generics.params.iter().collect::<Vec<_>>();
     let ident  = &decl.ident;
     let body   = match &decl.data {
         Data::Struct(data_struct) => body_for_struct(ident,data_struct),
@@ -193,10 +194,20 @@ pub fn derive
         Data::Union(_)            =>
             panic!("CloneRef cannot be derived for an untagged union input."),
     };
-    let bounds = decl.attrs.iter().filter_map(clone_ref_bounds).flatten();
+
+    let (impl_generics, ty_generics, inherent_where_clause_opt) = &decl.generics.split_for_impl();
+
+    // Where clause must contain both user-provided bounds and bounds inherent due to type
+    // declaration-level where clause.
+    let user_requested_bounds = decl.attrs.iter().filter_map(clone_ref_bounds).flatten();
+    let mut where_clause      = macro_utils::new_where_clause(user_requested_bounds);
+    for inherent_where_clause in inherent_where_clause_opt {
+        where_clause.predicates.extend(inherent_where_clause.predicates.iter().cloned())
+    }
+
     let output = quote!{
-        impl <#(#params),*> CloneRef for #ident<#(#params),*>
+        impl #impl_generics CloneRef for #ident #ty_generics
-        where #(#bounds),* {
+        #where_clause {
             fn clone_ref(&self) -> Self {
                 #body
             }