1 files changed, 61 insertions, 0 deletions
diff --git a/third_party/rust/derive_more-impl/src/mul_like.rs b/third_party/rust/derive_more-impl/src/mul_like.rs
new file mode 100644
index 0000000000..d06372f38a
--- /dev/null
+++ b/third_party/rust/derive_more-impl/src/mul_like.rs
@@ -0,0 +1,61 @@
+use crate::add_like;
+use crate::mul_helpers::generics_and_exprs;
+use crate::utils::{AttrParams, HashSet, MultiFieldData, RefType, State};
+use proc_macro2::TokenStream;
+use quote::{format_ident, quote};
+use std::iter;
+use syn::{DeriveInput, Result};
+
+pub fn expand(input: &DeriveInput, trait_name: &'static str) -> Result<TokenStream> {
+    let mut state = State::with_attr_params(
+        input,
+        trait_name,
+        trait_name.to_lowercase(),
+        AttrParams::struct_(vec!["forward"]),
+    )?;
+    if state.default_info.forward {
+        return Ok(add_like::expand(input, trait_name));
+    }
+
+    let scalar_ident = format_ident!("__RhsT");
+    state.add_trait_path_type_param(quote! { #scalar_ident });
+    let multi_field_data = state.enabled_fields_data();
+    let MultiFieldData {
+        input_type,
+        field_types,
+        ty_generics,
+        trait_path,
+        trait_path_with_params,
+        method_ident,
+        ..
+    } = multi_field_data.clone();
+
+    let tys = field_types.iter().collect::<HashSet<_>>();
+    let tys = tys.iter();
+    let scalar_iter = iter::repeat(&scalar_ident);
+    let trait_path_iter = iter::repeat(trait_path);
+
+    let type_where_clauses = quote! {
+        where #(#tys: #trait_path_iter<#scalar_iter, Output=#tys>),*
+    };
+
+    let (generics, initializers) = generics_and_exprs(
+        multi_field_data.clone(),
+        &scalar_ident,
+        type_where_clauses,
+        RefType::No,
+    );
+    let body = multi_field_data.initializer(&initializers);
+    let (impl_generics, _, where_clause) = generics.split_for_impl();
+    Ok(quote! {
+        #[automatically_derived]
+        impl #impl_generics  #trait_path_with_params for #input_type #ty_generics #where_clause {
+            type Output = #input_type #ty_generics;
+
+            #[inline]
+            fn #method_ident(self, rhs: #scalar_ident) -> #input_type #ty_generics {
+                #body
+            }
+        }
+    })
+}