diff options
Diffstat (limited to 'compiler/rustc_macros/src/type_foldable.rs')
| -rw-r--r-- | compiler/rustc_macros/src/type_foldable.rs | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/compiler/rustc_macros/src/type_foldable.rs b/compiler/rustc_macros/src/type_foldable.rs index 388e254cd..5ee4d8793 100644 --- a/compiler/rustc_macros/src/type_foldable.rs +++ b/compiler/rustc_macros/src/type_foldable.rs @@ -1,5 +1,5 @@ use quote::{quote, ToTokens}; -use syn::{parse_quote, Attribute, Meta, NestedMeta}; +use syn::parse_quote; pub fn type_foldable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { if let syn::Data::Union(_) = s.ast().data { @@ -17,21 +17,20 @@ pub fn type_foldable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2:: vi.construct(|_, index| { let bind = &bindings[index]; + let mut fixed = false; + // retain value of fields with #[type_foldable(identity)] - let fixed = bind - .ast() - .attrs - .iter() - .map(Attribute::parse_meta) - .filter_map(Result::ok) - .flat_map(|attr| match attr { - Meta::List(list) if list.path.is_ident("type_foldable") => list.nested, - _ => Default::default(), - }) - .any(|nested| match nested { - NestedMeta::Meta(Meta::Path(path)) => path.is_ident("identity"), - _ => false, + bind.ast().attrs.iter().for_each(|x| { + if !x.path().is_ident("type_foldable") { + return; + } + let _ = x.parse_nested_meta(|nested| { + if nested.path.is_ident("identity") { + fixed = true; + } + Ok(()) }); + }); if fixed { bind.to_token_stream() |