Add first_span to doc attribute

Author: JonathanBrouwer

compiler/rustc_attr_parsing/src/attributes/doc.rs

@@ -701,6 +701,9 @@ impl DocParser {
                 for i in items.mixed() {
                     match i {
                         MetaItemOrLitParser::MetaItemParser(mip) => {
+                            if self.nb_doc_attrs == 0 {
+                                self.attribute.first_span = cx.attr_span;
+                            }
                             self.nb_doc_attrs += 1;
                             self.parse_single_doc_attr_item(cx, mip);
                         }

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -544,6 +544,8 @@ pub struct CfgHideShow {
 
 #[derive(Clone, Debug, Default, HashStable_Generic, Decodable, PrintAttribute)]
 pub struct DocAttribute {
+    pub first_span: Span,
+
     pub aliases: FxIndexMap<Symbol, Span>,
     pub hidden: Option<Span>,
     // Because we need to emit the error if there is more than one `inline` attribute on an item
@@ -581,6 +583,7 @@ pub struct DocAttribute {
 impl<E: rustc_span::SpanEncoder> rustc_serialize::Encodable<E> for DocAttribute {
     fn encode(&self, encoder: &mut E) {
         let DocAttribute {
+            first_span,
             aliases,
             hidden,
             inline,
@@ -603,6 +606,7 @@ impl<E: rustc_span::SpanEncoder> rustc_serialize::Encodable<E> for DocAttribute
             test_attrs,
             no_crate_inject,
         } = self;
+        rustc_serialize::Encodable::<E>::encode(first_span, encoder);
         rustc_serialize::Encodable::<E>::encode(aliases, encoder);
         rustc_serialize::Encodable::<E>::encode(hidden, encoder);
 

compiler/rustc_passes/src/check_attr.rs

@@ -1027,6 +1027,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     /// [`check_doc_inline`]: Self::check_doc_inline
     fn check_doc_attrs(&self, attr: &DocAttribute, hir_id: HirId, target: Target) {
         let DocAttribute {
+            first_span: _,
             aliases,
             // valid pretty much anywhere, not checked here?
             // FIXME: should we?

src/librustdoc/clean/mod.rs

@@ -2780,6 +2780,7 @@ fn add_without_unwanted_attributes<'hir>(
             hir::Attribute::Parsed(AttributeKind::Doc(box d)) => {
                 // Remove attributes from `normal` that should not be inherited by `use` re-export.
                 let DocAttribute {
+                    first_span: _,
                     aliases,
                     hidden,
                     inline,

src/librustdoc/json/conversions.rs

@@ -960,6 +960,7 @@ fn maybe_from_hir_attr(attr: &hir::Attribute, item_id: ItemId, tcx: TyCtxt<'_>)
             }
 
             let DocAttribute {
+                first_span: _,
                 aliases,
                 hidden,
                 inline,