From b4a05c3621964bb2d5d8e9bf9ccb651aebf4f7ff Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Wed, 30 Dec 2020 15:37:01 -0800
Subject: [PATCH] Preserve doc attributes on struct fields

---
 macro/src/expand.rs               |  3 ++-
 syntax/impls.rs                   |  3 +++
 syntax/mod.rs                     |  1 +
 syntax/parse.rs                   | 14 ++++++++++++++
 tests/ui/deny_missing_docs.stderr |  6 ------
 5 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/macro/src/expand.rs b/macro/src/expand.rs
index 8ba765af..3b031155 100644
--- a/macro/src/expand.rs
+++ b/macro/src/expand.rs
@@ -155,10 +155,11 @@ fn expand_struct(strct: &Struct) -> TokenStream {
     let doc = &strct.doc;
     let type_id = type_id(&strct.name);
     let fields = strct.fields.iter().map(|field| {
+        let doc = &field.doc;
         // This span on the pub makes "private type in public interface" errors
         // appear in the right place.
         let vis = field.visibility;
-        quote!(#vis #field)
+        quote!(#doc #vis #field)
     });
     let mut derives = None;
     let derived_traits = derive::expand_struct(strct, &mut derives);
diff --git a/syntax/impls.rs b/syntax/impls.rs
index c7e1a2c2..624a64d4 100644
--- a/syntax/impls.rs
+++ b/syntax/impls.rs
@@ -297,11 +297,13 @@ impl Eq for Var {}
 impl PartialEq for Var {
     fn eq(&self, other: &Var) -> bool {
         let Var {
+            doc: _,
             visibility: _,
             ident,
             ty,
         } = self;
         let Var {
+            doc: _,
             visibility: _,
             ident: ident2,
             ty: ty2,
@@ -313,6 +315,7 @@ impl PartialEq for Var {
 impl Hash for Var {
     fn hash<H: Hasher>(&self, state: &mut H) {
         let Var {
+            doc: _,
             visibility: _,
             ident,
             ty,
diff --git a/syntax/mod.rs b/syntax/mod.rs
index f6bdf72e..092f4037 100644
--- a/syntax/mod.rs
+++ b/syntax/mod.rs
@@ -150,6 +150,7 @@ pub struct Signature {
 }
 
 pub struct Var {
+    pub doc: Doc,
     pub visibility: Token![pub],
     pub ident: Ident,
     pub ty: Type,
diff --git a/syntax/parse.rs b/syntax/parse.rs
index 4bfabcd5..3d970d83 100644
--- a/syntax/parse.rs
+++ b/syntax/parse.rs
@@ -97,6 +97,15 @@ fn parse_struct(cx: &mut Errors, item: ItemStruct, namespace: &Namespace) -> Res
     let mut fields = Vec::new();
     for field in named_fields.named {
         let ident = field.ident.unwrap();
+        let mut doc = Doc::new();
+        attrs::parse(
+            cx,
+            &field.attrs,
+            attrs::Parser {
+                doc: Some(&mut doc),
+                ..Default::default()
+            },
+        );
         let ty = match parse_type(&field.ty) {
             Ok(ty) => ty,
             Err(err) => {
@@ -111,6 +120,7 @@ fn parse_struct(cx: &mut Errors, item: ItemStruct, namespace: &Namespace) -> Res
             Visibility::Inherited => ident.span(),
         });
         fields.push(Var {
+            doc,
             visibility,
             ident,
             ty,
@@ -527,8 +537,10 @@ fn parse_extern_fn(
                 };
                 let ty = parse_type(&arg.ty)?;
                 if ident != "self" {
+                    let doc = Doc::new();
                     let visibility = Token![pub](ident.span());
                     args.push_value(Var {
+                        doc,
                         visibility,
                         ident,
                         ty,
@@ -1098,8 +1110,10 @@ fn parse_type_fn(ty: &TypeBareFn) -> Result<Type> {
                 Some(ident) => ident.0.clone(),
                 None => format_ident!("arg{}", i),
             };
+            let doc = Doc::new();
             let visibility = Token![pub](ident.span());
             Ok(Var {
+                doc,
                 visibility,
                 ident,
                 ty,
diff --git a/tests/ui/deny_missing_docs.stderr b/tests/ui/deny_missing_docs.stderr
index 96dec460..f31be34a 100644
--- a/tests/ui/deny_missing_docs.stderr
+++ b/tests/ui/deny_missing_docs.stderr
@@ -16,12 +16,6 @@ error: missing documentation for a struct field
 12 |         pub undocumented_field: u8,
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: missing documentation for a struct field
-  --> $DIR/deny_missing_docs.rs:18:9
-   |
-18 |         pub documented_field: u8,
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-
 error: missing documentation for a struct
  --> $DIR/deny_missing_docs.rs:9:1
   |