Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/third_party/rust/derive_more/src/deref.rs b/third_party/rust/derive_more/src/deref.rs
new file mode 100644
index 0000000000..c7a8008cbd
--- /dev/null
+++ b/third_party/rust/derive_more/src/deref.rs
@@ -0,0 +1,46 @@
+use crate::utils::{SingleFieldData, State};
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::{parse::Result, DeriveInput};
+
+/// Provides the hook to expand `#[derive(Deref)]` into an implementation of `Deref`
+pub fn expand(input: &DeriveInput, trait_name: &'static str) -> Result<TokenStream> {
+    let state = State::with_field_ignore_and_forward(
+        input,
+        trait_name,
+        quote!(::core::ops),
+        trait_name.to_lowercase(),
+    )?;
+    let SingleFieldData {
+        input_type,
+        field_type,
+        trait_path,
+        casted_trait,
+        impl_generics,
+        ty_generics,
+        where_clause,
+        member,
+        info,
+        ..
+    } = state.assert_single_enabled_field();
+
+    let (target, body) = if info.forward {
+        (
+            quote!(#casted_trait::Target),
+            quote!(#casted_trait::deref(&#member)),
+        )
+    } else {
+        (quote!(#field_type), quote!(&#member))
+    };
+
+    Ok(quote! {
+        impl#impl_generics #trait_path for #input_type#ty_generics #where_clause
+        {
+            type Target = #target;
+            #[inline]
+            fn deref(&self) -> &Self::Target {
+                #body
+            }
+        }
+    })
+}