Add docs to struct fields

crates/ra_hir/src/code_model_api.rs

@@ -216,6 +216,15 @@ impl StructField {
     }
 }
 
+impl Docs for StructField {
+    fn docs(&self, db: &impl HirDatabase) -> Option<Documentation> {
+        match self.source(db).1 {
+            FieldSource::Named(named) => docs_from_ast(&*named),
+            FieldSource::Pos(..) => return None,
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Struct {
     pub(crate) id: StructId,

crates/ra_ide_api/src/completion/complete_dot.rs

@@ -1,4 +1,4 @@
-use hir::{Ty, AdtDef};
+use hir::{Ty, AdtDef, Docs};
 
 use crate::completion::{CompletionContext, Completions, CompletionItem, CompletionItemKind};
 use crate::completion::completion_item::CompletionKind;
@@ -38,6 +38,7 @@ fn complete_fields(acc: &mut Completions, ctx: &CompletionContext, receiver: Ty)
                             )
                             .kind(CompletionItemKind::Field)
                             .detail(field.ty(ctx.db).subst(substs).to_string())
+                            .set_documentation(field.docs(ctx.db))
                             .add_to(acc);
                         }
                     }
@@ -107,7 +108,10 @@ mod tests {
         check_ref_completion(
             "struct_field_completion_self",
             r"
-            struct A { the_field: (u32,) }
+            struct A {
+                /// This is the_field
+                the_field: (u32,)
+            }
             impl A {
                 fn foo(self) {
                     self.<|>

crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_self.snap

@@ -1,5 +1,5 @@
 ---
-created: "2019-01-23T13:19:23.501297515+00:00"
+created: "2019-01-25T19:27:09.519688600+00:00"
 creator: insta@0.5.2
 expression: kind_completions
 source: crates/ra_ide_api/src/completion/completion_item.rs
@@ -14,11 +14,15 @@ source: crates/ra_ide_api/src/completion/completion_item.rs
         detail: Some(
             "(u32,)"
         ),
-        documentation: None,
+        documentation: Some(
+            Documentation(
+                "This is the_field"
+            )
+        ),
         lookup: None,
         insert_text: None,
         insert_text_format: PlainText,
-        source_range: [121; 121),
+        source_range: [187; 187),
         text_edit: None
     },
     CompletionItem {
@@ -36,7 +40,7 @@ source: crates/ra_ide_api/src/completion/completion_item.rs
             "foo()$0"
         ),
         insert_text_format: Snippet,
-        source_range: [121; 121),
+        source_range: [187; 187),
         text_edit: None
     }
 ]

crates/ra_syntax/src/ast/generated.rs

@@ -2248,6 +2248,7 @@ impl ToOwned for NamedFieldDef {
 impl ast::VisibilityOwner for NamedFieldDef {}
 impl ast::NameOwner for NamedFieldDef {}
 impl ast::AttrsOwner for NamedFieldDef {}
+impl ast::DocCommentsOwner for NamedFieldDef {}
 impl NamedFieldDef {
     pub fn type_ref(&self) -> Option<&TypeRef> {
         super::child_opt(self)

crates/ra_syntax/src/grammar.ron

@@ -268,7 +268,7 @@ Grammar(
             ]
         ),
         "NamedFieldDefList": (collections: [["fields", "NamedFieldDef"]]),
-        "NamedFieldDef": ( traits: ["VisibilityOwner", "NameOwner", "AttrsOwner"], options: ["TypeRef"] ),
+        "NamedFieldDef": ( traits: ["VisibilityOwner", "NameOwner", "AttrsOwner", "DocCommentsOwner"], options: ["TypeRef"] ),
         "PosFieldList": (collections: [["fields", "PosField"]]),
         "PosField": ( traits: ["VisibilityOwner", "AttrsOwner"], options: ["TypeRef"]),
         "EnumDef": ( traits: [

crates/ra_syntax/src/parser_impl/event.rs

@@ -250,7 +250,7 @@ fn n_attached_trivias<'a>(
 ) -> usize {
     match kind {
         CONST_DEF | TYPE_DEF | STRUCT_DEF | ENUM_DEF | ENUM_VARIANT | FN_DEF | TRAIT_DEF
-        | MODULE => {
+        | MODULE | NAMED_FIELD_DEF => {
             let mut res = 0;
             for (i, (kind, text)) in trivias.enumerate() {
                 match kind {