Document what feature everything requires

codegen/src/main.rs

@@ -1026,6 +1026,8 @@ use gen::helper::fold::*;
 /// See the [module documentation] for details.
 ///
 /// [module documentation]: index.html
+///
+/// *This trait is available if Syn is built with the `\"fold\"` feature.*
 pub trait Fold {{
 {fold_trait}
 }}
@@ -1086,6 +1088,8 @@ use gen::helper::visit::*;
 /// See the [module documentation] for details.
 ///
 /// [module documentation]: index.html
+///
+/// *This trait is available if Syn is built with the `\"visit\"` feature.*
 pub trait Visit<'ast> {{
 {visit_trait}
 }}
@@ -1122,6 +1126,8 @@ use gen::helper::visit_mut::*;
 /// See the [module documentation] for details.
 ///
 /// [module documentation]: index.html
+///
+/// *This trait is available if Syn is built with the `\"visit-mut\"` feature.*
 pub trait VisitMut {{
 {visit_mut_trait}
 }}

src/attr.rs

@@ -21,6 +21,9 @@ use tt::TokenStreamHelper;
 ast_struct! {
     /// An attribute like `#[repr(transparent)]`.
     ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
     /// # Syntax
     ///
     /// Rust has six types of attributes.
@@ -225,6 +228,9 @@ ast_enum! {
     /// Distinguishes between attributes that decorate an item and attributes
     /// that are contained within an item.
     ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
     /// # Outer attributes
     ///
     /// - `#[repr(transparent)]`
@@ -246,6 +252,9 @@ ast_enum! {
 ast_enum_of_structs! {
     /// Content of a compile-time structured attribute.
     ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
     /// ## Word
     ///
     /// A meta word is like the `test` in `#[test]`.
@@ -267,12 +276,18 @@ ast_enum_of_structs! {
     pub enum Meta {
         pub Word(Ident),
         /// A structured list within an attribute, like `derive(Copy, Clone)`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub List(MetaList {
             pub ident: Ident,
             pub paren_token: token::Paren,
             pub nested: Punctuated<NestedMeta, Token![,]>,
         }),
         /// A name-value pair within an attribute, like `feature = "nightly"`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub NameValue(MetaNameValue {
             pub ident: Ident,
             pub eq_token: Token![=],
@@ -297,6 +312,9 @@ impl Meta {
 
 ast_enum_of_structs! {
     /// Element of a compile-time attribute list.
+    ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
     pub enum NestedMeta {
         /// A structured meta item, like the `Copy` in `#[derive(Copy)]` which
         /// would be a nested `Meta::Word`.

src/buffer.rs

@@ -14,6 +14,8 @@
 //!
 //! [`Synom`]: ../synom/trait.Synom.html
 //!
+//! *This module is available if Syn is built with the `"parsing"` feature.*
+//!
 //! # Example
 //!
 //! This example shows a basic token parser for parsing a token stream without
@@ -154,6 +156,8 @@ enum Entry {
 /// See the [module documentation] for an example of `TokenBuffer` in action.
 ///
 /// [module documentation]: index.html
+///
+/// *This type is available if Syn is built with the `"parsing"` feature.*
 pub struct TokenBuffer {
     // NOTE: Do not derive clone on this - there are raw pointers inside which
     // will be messed up. Moving the `TokenBuffer` itself is safe as the actual
@@ -246,6 +250,8 @@ impl TokenBuffer {
 /// See the [module documentation] for an example of a `Cursor` in action.
 ///
 /// [module documentation]: index.html
+///
+/// *This type is available if Syn is built with the `"parsing"` feature.*
 #[derive(Copy, Clone, Eq, PartialEq)]
 pub struct Cursor<'a> {
     /// The current entry which the `Cursor` is pointing at.

src/data.rs

@@ -11,6 +11,9 @@ use punctuated::Punctuated;
 
 ast_struct! {
     /// An enum variant.
+    ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
     pub struct Variant {
         /// Attributes tagged on the variant.
         pub attrs: Vec<Attribute>,
@@ -29,6 +32,9 @@ ast_struct! {
 ast_enum_of_structs! {
     /// Data stored within an enum variant or struct.
     ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
     /// # Syntax tree enum
     ///
     /// This type is a [syntax tree enum].
@@ -37,12 +43,18 @@ ast_enum_of_structs! {
     pub enum Fields {
         /// Named fields of a struct or struct variant such as `Point { x: f64,
         /// y: f64 }`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub Named(FieldsNamed {
             pub brace_token: token::Brace,
             pub named: Punctuated<Field, Token![,]>,
         }),
 
         /// Unnamed fields of a tuple struct or tuple variant such as `Some(T)`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub Unnamed(FieldsUnnamed {
             pub paren_token: token::Paren,
             pub unnamed: Punctuated<Field, Token![,]>,
@@ -55,6 +67,9 @@ ast_enum_of_structs! {
 
 ast_struct! {
     /// A field of a struct or enum variant.
+    ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
     pub struct Field {
         /// Attributes tagged on the field.
         pub attrs: Vec<Attribute>,
@@ -78,18 +93,27 @@ ast_enum_of_structs! {
     /// The visibility level of an item: inherited or `pub` or
     /// `pub(restricted)`.
     ///
+    /// *This type is available if Syn is built with the `"derive"` or `"full"`
+    /// feature.*
+    ///
     /// # Syntax tree enum
     ///
     /// This type is a [syntax tree enum].
     ///
     /// [syntax tree enum]: enum.Expr.html#syntax-tree-enums
     pub enum Visibility {
         /// A public visibility level: `pub`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub Public(VisPublic {
             pub pub_token: Token![pub],
         }),
 
         /// A crate-level visibility: `pub(crate)`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub Crate(VisCrate {
             pub pub_token: Token![pub],
             pub paren_token: token::Paren,
@@ -98,6 +122,9 @@ ast_enum_of_structs! {
 
         /// A visibility level restricted to some path: `pub(self)` or
         /// `pub(super)` or `pub(in some::module)`.
+        ///
+        /// *This type is available if Syn is built with the `"derive"` or
+        /// `"full"` feature.*
         pub Restricted(VisRestricted {
             pub pub_token: Token![pub],
             pub paren_token: token::Paren,

src/derive.rs

@@ -11,6 +11,8 @@ use punctuated::Punctuated;
 
 ast_struct! {
     /// Data structure sent to a `proc_macro_derive` macro.
+    ///
+    /// *This type is available if Syn is built with the `"derive"` feature.*
     pub struct DeriveInput {
         /// Attributes tagged on the whole struct or enum.
         pub attrs: Vec<Attribute>,
@@ -32,27 +34,38 @@ ast_struct! {
 ast_enum_of_structs! {
     /// The storage of a struct, enum or union data structure.
     ///
+    /// *This type is available if Syn is built with the `"derive"` feature.*
+    ///
     /// # Syntax tree enum
     ///
     /// This type is a [syntax tree enum].
     ///
     /// [syntax tree enum]: enum.Expr.html#syntax-tree-enums
     pub enum Data {
         /// A struct input to a `proc_macro_derive` macro.
+        ///
+        /// *This type is available if Syn is built with the `"derive"`
+        /// feature.*
         pub Struct(DataStruct {
             pub struct_token: Token![struct],
             pub fields: Fields,
             pub semi_token: Option<Token![;]>,
         }),
 
         /// An enum input to a `proc_macro_derive` macro.
+        ///
+        /// *This type is available if Syn is built with the `"derive"`
+        /// feature.*
         pub Enum(DataEnum {
             pub enum_token: Token![enum],
             pub brace_token: token::Brace,
             pub variants: Punctuated<Variant, Token![,]>,
         }),
 
         /// A tagged union input to a `proc_macro_derive` macro.
+        ///
+        /// *This type is available if Syn is built with the `"derive"`
+        /// feature.*
         pub Union(DataUnion {
             pub union_token: Token![union],
             pub fields: FieldsNamed,

src/error.rs

@@ -15,6 +15,8 @@ use std::fmt::{self, Display};
 /// Refer to the [module documentation] for details about parsing in Syn.
 ///
 /// [module documentation]: index.html
+///
+/// *This type is available if Syn is built with the `"parsing"` feature.*
 pub type PResult<'a, O> = Result<(O, Cursor<'a>), ParseError>;
 
 /// An error with a default error message.
@@ -29,6 +31,8 @@ pub fn parse_error<O>() -> PResult<'static, O> {
 /// Refer to the [module documentation] for details about parsing in Syn.
 ///
 /// [module documentation]: index.html
+///
+/// *This type is available if Syn is built with the `"parsing"` feature.*
 #[derive(Debug)]
 pub struct ParseError(Option<String>);