1 files changed, 48 insertions, 0 deletions
diff --git a/third_party/rust/serde_derive/src/dummy.rs b/third_party/rust/serde_derive/src/dummy.rs
new file mode 100644
index 0000000000..a02bd37626
--- /dev/null
+++ b/third_party/rust/serde_derive/src/dummy.rs
@@ -0,0 +1,48 @@
+use proc_macro2::{Ident, TokenStream};
+use quote::format_ident;
+
+use syn;
+use try;
+
+pub fn wrap_in_const(
+    serde_path: Option<&syn::Path>,
+    trait_: &str,
+    ty: &Ident,
+    code: TokenStream,
+) -> TokenStream {
+    let try_replacement = try::replacement();
+
+    let dummy_const = if cfg!(no_underscore_consts) {
+        format_ident!("_IMPL_{}_FOR_{}", trait_, unraw(ty))
+    } else {
+        format_ident!("_")
+    };
+
+    let use_serde = match serde_path {
+        Some(path) => quote! {
+            use #path as _serde;
+        },
+        None => quote! {
+            #[allow(unused_extern_crates, clippy::useless_attribute)]
+            extern crate serde as _serde;
+        },
+    };
+
+    quote! {
+        #[doc(hidden)]
+        #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+        const #dummy_const: () = {
+            #use_serde
+            #try_replacement
+            #code
+        };
+    }
+}
+
+#[allow(deprecated)]
+fn unraw(ident: &Ident) -> String {
+    // str::trim_start_matches was added in 1.30, trim_left_matches deprecated
+    // in 1.33. We currently support rustc back to 1.15 so we need to continue
+    // to use the deprecated one.
+    ident.to_string().trim_left_matches("r#").to_owned()
+}