Apply #[doc(cfg(feature = "..."))] banners in docs

Cargo.toml

@@ -61,6 +61,7 @@ required-features = ["full", "parsing"]
 
 [package.metadata.docs.rs]
 all-features = true
+rustdoc-args = ["--cfg", "syn_enable_doc_cfg"]
 
 [package.metadata.playground]
 all-features = true

src/attr.rs

@@ -148,6 +148,10 @@ ast_struct! {
     /// };
     /// assert_eq!(doc, attr);
     /// ```
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct Attribute #manual_extra_traits {
         pub pound_token: Token![#],
         pub style: AttrStyle,
@@ -192,6 +196,7 @@ impl Attribute {
     /// *This function is available if Syn is built with the `"parsing"`
     /// feature.*
     #[cfg(feature = "parsing")]
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "parsing")))]
     pub fn parse_meta(&self) -> Result<Meta> {
         fn clone_ident_segment(segment: &PathSegment) -> PathSegment {
             PathSegment {
@@ -239,6 +244,7 @@ impl Attribute {
     /// *This function is available if Syn is built with the `"parsing"`
     /// feature.*
     #[cfg(feature = "parsing")]
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "parsing")))]
     pub fn parse_args<T: Parse>(&self) -> Result<T> {
         self.parse_args_with(T::parse)
     }
@@ -248,6 +254,7 @@ impl Attribute {
     /// *This function is available if Syn is built with the `"parsing"`
     /// feature.*
     #[cfg(feature = "parsing")]
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "parsing")))]
     pub fn parse_args_with<F: Parser>(&self, parser: F) -> Result<F::Output> {
         let parser = |input: ParseStream| {
             let args = enter_args(self, input)?;
@@ -261,6 +268,7 @@ impl Attribute {
     /// *This function is available if Syn is built with the `"parsing"`
     /// feature.*
     #[cfg(feature = "parsing")]
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "parsing")))]
     pub fn parse_outer(input: ParseStream) -> Result<Vec<Self>> {
         let mut attrs = Vec::new();
         while input.peek(Token![#]) {
@@ -274,6 +282,7 @@ impl Attribute {
     /// *This function is available if Syn is built with the `"parsing"`
     /// feature.*
     #[cfg(feature = "parsing")]
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "parsing")))]
     pub fn parse_inner(input: ParseStream) -> Result<Vec<Self>> {
         let mut attrs = Vec::new();
         while input.peek(Token![#]) && input.peek2(Token![!]) {
@@ -349,6 +358,10 @@ ast_enum! {
     /// - `#![feature(proc_macro)]`
     /// - `//! # Example`
     /// - `/*! Please file an issue */`
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     #[cfg_attr(feature = "clone-impls", derive(Copy))]
     pub enum AttrStyle {
         Outer,
@@ -383,6 +396,10 @@ ast_enum_of_structs! {
     //
     // TODO: change syntax-tree-enum link to an intra rustdoc link, currently
     // blocked on https://github.com/rust-lang/rust/issues/62833
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub enum Meta {
         Path(Path),
 
@@ -399,6 +416,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct MetaList {
         pub path: Path,
         pub paren_token: token::Paren,
@@ -411,6 +432,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct MetaNameValue {
         pub path: Path,
         pub eq_token: Token![=],
@@ -437,6 +462,10 @@ ast_enum_of_structs! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or `"full"`
     /// feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub enum NestedMeta {
         /// A structured meta item, like the `Copy` in `#[derive(Copy)]` which
         /// would be a nested `Meta::Path`.
@@ -482,6 +511,10 @@ ast_enum_of_structs! {
 /// #   "".parse().unwrap()
 /// }
 /// ```
+#[cfg_attr(
+    syn_enable_doc_cfg,
+    doc(cfg(any(feature = "derive", feature = "full")))
+)]
 pub type AttributeArgs = Vec<NestedMeta>;
 
 pub trait FilterAttrs<'a> {

src/data.rs

@@ -6,6 +6,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or `"full"`
     /// feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct Variant {
         /// Attributes tagged on the variant.
         pub attrs: Vec<Attribute>,
@@ -35,6 +39,10 @@ ast_enum_of_structs! {
     //
     // TODO: change syntax-tree-enum link to an intra rustdoc link, currently
     // blocked on https://github.com/rust-lang/rust/issues/62833
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub enum Fields {
         /// Named fields of a struct or struct variant such as `Point { x: f64,
         /// y: f64 }`.
@@ -54,6 +62,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct FieldsNamed {
         pub brace_token: token::Brace,
         pub named: Punctuated<Field, Token![,]>,
@@ -65,6 +77,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct FieldsUnnamed {
         pub paren_token: token::Paren,
         pub unnamed: Punctuated<Field, Token![,]>,
@@ -149,6 +165,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or `"full"`
     /// feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct Field {
         /// Attributes tagged on the field.
         pub attrs: Vec<Attribute>,
@@ -183,6 +203,10 @@ ast_enum_of_structs! {
     //
     // TODO: change syntax-tree-enum link to an intra rustdoc link, currently
     // blocked on https://github.com/rust-lang/rust/issues/62833
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub enum Visibility {
         /// A public visibility level: `pub`.
         Public(VisPublic),
@@ -204,6 +228,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct VisPublic {
         pub pub_token: Token![pub],
     }
@@ -214,6 +242,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct VisCrate {
         pub crate_token: Token![crate],
     }
@@ -225,6 +257,10 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"` or
     /// `"full"` feature.*
+    #[cfg_attr(
+        syn_enable_doc_cfg,
+        doc(cfg(any(feature = "derive", feature = "full")))
+    )]
     pub struct VisRestricted {
         pub pub_token: Token![pub],
         pub paren_token: token::Paren,

src/derive.rs

@@ -5,6 +5,7 @@ ast_struct! {
     /// Data structure sent to a `proc_macro_derive` macro.
     ///
     /// *This type is available if Syn is built with the `"derive"` feature.*
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "derive")))]
     pub struct DeriveInput {
         /// Attributes tagged on the whole struct or enum.
         pub attrs: Vec<Attribute>,
@@ -36,6 +37,7 @@ ast_enum_of_structs! {
     //
     // TODO: change syntax-tree-enum link to an intra rustdoc link, currently
     // blocked on https://github.com/rust-lang/rust/issues/62833
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "derive")))]
     pub enum Data {
         /// A struct input to a `proc_macro_derive` macro.
         Struct(DataStruct),
@@ -55,6 +57,7 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"`
     /// feature.*
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "derive")))]
     pub struct DataStruct {
         pub struct_token: Token![struct],
         pub fields: Fields,
@@ -67,6 +70,7 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"`
     /// feature.*
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "derive")))]
     pub struct DataEnum {
         pub enum_token: Token![enum],
         pub brace_token: token::Brace,
@@ -79,6 +83,7 @@ ast_struct! {
     ///
     /// *This type is available if Syn is built with the `"derive"`
     /// feature.*
+    #[cfg_attr(syn_enable_doc_cfg, doc(cfg(feature = "derive")))]
     pub struct DataUnion {
         pub union_token: Token![union],
         pub fields: FieldsNamed,