adt: correctly inherit field visibility from enum

Previously, "find all references" on a variant field wouldn't find any
references outside the defining module. This is because variant fields
were incorrectly assumed to be private, like struct fields without
explicit visibility, but they actually inherit the enum's visibility.

crates/assists/src/handlers/fix_visibility.rs

@@ -324,14 +324,14 @@ pub struct Foo { pub bar: () }
 
     #[test]
     fn fix_visibility_of_enum_variant_field() {
-        check_assist(
+        // Enum variants, as well as their fields, always get the enum's visibility. In fact, rustc
+        // rejects any visibility specifiers on them, so this assist should never fire on them.
+        check_assist_not_applicable(
             fix_visibility,
             r"mod foo { pub enum Foo { Bar { bar: () } } }
               fn main() { foo::Foo::Bar { <|>bar: () }; } ",
-            r"mod foo { pub enum Foo { Bar { $0pub(crate) bar: () } } }
-              fn main() { foo::Foo::Bar { bar: () }; } ",
         );
-        check_assist(
+        check_assist_not_applicable(
             fix_visibility,
             r"
 //- /lib.rs
@@ -339,8 +339,6 @@ mod foo;
 fn main() { foo::Foo::Bar { <|>bar: () }; }
 //- /foo.rs
 pub enum Foo { Bar { bar: () } }
-",
-            r"pub enum Foo { Bar { $0pub(crate) bar: () } }
 ",
         );
         check_assist_not_applicable(

crates/hir_def/src/adt.rs

@@ -14,7 +14,7 @@ use tt::{Delimiter, DelimiterKind, Leaf, Subtree, TokenTree};
 use crate::{
     body::{CfgExpander, LowerCtx},
     db::DefDatabase,
-    item_tree::{AttrOwner, Field, Fields, ItemTree, ModItem},
+    item_tree::{AttrOwner, Field, Fields, ItemTree, ModItem, RawVisibilityId},
     src::HasChildSource,
     src::HasSource,
     trace::Trace,
@@ -91,7 +91,7 @@ impl StructData {
         let cfg_options = db.crate_graph()[loc.container.module(db).krate].cfg_options.clone();
 
         let strukt = &item_tree[loc.id.value];
-        let variant_data = lower_fields(&item_tree, &cfg_options, &strukt.fields);
+        let variant_data = lower_fields(&item_tree, &cfg_options, &strukt.fields, None);
         Arc::new(StructData {
             name: strukt.name.clone(),
             variant_data: Arc::new(variant_data),
@@ -105,7 +105,7 @@ impl StructData {
         let cfg_options = db.crate_graph()[loc.container.module(db).krate].cfg_options.clone();
 
         let union = &item_tree[loc.id.value];
-        let variant_data = lower_fields(&item_tree, &cfg_options, &union.fields);
+        let variant_data = lower_fields(&item_tree, &cfg_options, &union.fields, None);
 
         Arc::new(StructData {
             name: union.name.clone(),
@@ -126,7 +126,8 @@ impl EnumData {
         for var_id in enum_.variants.clone() {
             if item_tree.attrs(var_id.into()).is_cfg_enabled(&cfg_options) {
                 let var = &item_tree[var_id];
-                let var_data = lower_fields(&item_tree, &cfg_options, &var.fields);
+                let var_data =
+                    lower_fields(&item_tree, &cfg_options, &var.fields, Some(enum_.visibility));
 
                 variants.alloc(EnumVariantData {
                     name: var.name.clone(),
@@ -296,13 +297,18 @@ fn lower_struct(
     }
 }
 
-fn lower_fields(item_tree: &ItemTree, cfg_options: &CfgOptions, fields: &Fields) -> VariantData {
+fn lower_fields(
+    item_tree: &ItemTree,
+    cfg_options: &CfgOptions,
+    fields: &Fields,
+    override_visibility: Option<RawVisibilityId>,
+) -> VariantData {
     match fields {
         Fields::Record(flds) => {
             let mut arena = Arena::new();
             for field_id in flds.clone() {
                 if item_tree.attrs(field_id.into()).is_cfg_enabled(cfg_options) {
-                    arena.alloc(lower_field(item_tree, &item_tree[field_id]));
+                    arena.alloc(lower_field(item_tree, &item_tree[field_id], override_visibility));
                 }
             }
             VariantData::Record(arena)
@@ -311,7 +317,7 @@ fn lower_fields(item_tree: &ItemTree, cfg_options: &CfgOptions, fields: &Fields)
             let mut arena = Arena::new();
             for field_id in flds.clone() {
                 if item_tree.attrs(field_id.into()).is_cfg_enabled(cfg_options) {
-                    arena.alloc(lower_field(item_tree, &item_tree[field_id]));
+                    arena.alloc(lower_field(item_tree, &item_tree[field_id], override_visibility));
                 }
             }
             VariantData::Tuple(arena)
@@ -320,10 +326,14 @@ fn lower_fields(item_tree: &ItemTree, cfg_options: &CfgOptions, fields: &Fields)
     }
 }
 
-fn lower_field(item_tree: &ItemTree, field: &Field) -> FieldData {
+fn lower_field(
+    item_tree: &ItemTree,
+    field: &Field,
+    override_visibility: Option<RawVisibilityId>,
+) -> FieldData {
     FieldData {
         name: field.name.clone(),
         type_ref: field.type_ref.clone(),
-        visibility: item_tree[field.visibility].clone(),
+        visibility: item_tree[override_visibility.unwrap_or(field.visibility)].clone(),
     }
 }

crates/ide/src/references.rs

@@ -732,6 +732,30 @@ fn f(e: En) {
         );
     }
 
+    #[test]
+    fn test_find_all_refs_enum_var_privacy() {
+        check(
+            r#"
+mod m {
+    pub enum En {
+        Variant {
+            field<|>: u8,
+        }
+    }
+}
+
+fn f() -> m::En {
+    m::En::Variant { field: 0 }
+}
+"#,
+            expect![[r#"
+                field RECORD_FIELD FileId(0) 56..65 56..61 Other
+
+                FileId(0) 125..130 Other Read
+            "#]],
+        );
+    }
+
     fn check(ra_fixture: &str, expect: Expect) {
         check_with_scope(ra_fixture, None, expect)
     }