Auto merge of #15050 - alibektas:14957, r=Veykril

bugfix :  skip doc(hidden) default members

fixes  #14957 . I have two questions :

1.  I am definitely looking for a more idiomatic way for the things I added in `crates/ide-assists/src/utils.rs`. See `FIXME` in that file.
2. Would it be actually better to change `DefaultMethods` to something like

```rust
enum DefaultMethods {
     Only( IgnoreHidden ( bool ) ) ,
     None
}
```

instead of adding a boolean to every function that calls `crates/ide-assists/src/utils.rs::filter_assoc_items`

crates/ide-assists/src/handlers/add_missing_impl_members.rs

@@ -3,7 +3,10 @@
 
 use crate::{
     assist_context::{AssistContext, Assists},
-    utils::{add_trait_assoc_items_to_impl, filter_assoc_items, gen_trait_fn_body, DefaultMethods},
+    utils::{
+        add_trait_assoc_items_to_impl, filter_assoc_items, gen_trait_fn_body, DefaultMethods,
+        IgnoreAssocItems,
+    },
     AssistId, AssistKind,
 };
 
@@ -43,6 +46,7 @@ pub(crate) fn add_missing_impl_members(acc: &mut Assists, ctx: &AssistContext<'_
         acc,
         ctx,
         DefaultMethods::No,
+        IgnoreAssocItems::DocHiddenAttrPresent,
         "add_impl_missing_members",
         "Implement missing members",
     )
@@ -87,6 +91,7 @@ pub(crate) fn add_missing_default_members(
         acc,
         ctx,
         DefaultMethods::Only,
+        IgnoreAssocItems::DocHiddenAttrPresent,
         "add_impl_default_members",
         "Implement default members",
     )
@@ -96,6 +101,7 @@ fn add_missing_impl_members_inner(
     acc: &mut Assists,
     ctx: &AssistContext<'_>,
     mode: DefaultMethods,
+    ignore_items: IgnoreAssocItems,
     assist_id: &'static str,
     label: &'static str,
 ) -> Option<()> {
@@ -115,10 +121,21 @@ fn add_missing_impl_members_inner(
     let trait_ref = impl_.trait_ref(ctx.db())?;
     let trait_ = trait_ref.trait_();
 
+    let mut ign_item = ignore_items;
+
+    if let IgnoreAssocItems::DocHiddenAttrPresent = ignore_items {
+        // Relax condition for local crates.
+        let db = ctx.db();
+        if trait_.module(db).krate().origin(db).is_local() {
+            ign_item = IgnoreAssocItems::No;
+        }
+    }
+
     let missing_items = filter_assoc_items(
         &ctx.sema,
         &ide_db::traits::get_missing_assoc_items(&ctx.sema, &impl_def),
         mode,
+        ign_item,
     );
 
     if missing_items.is_empty() {
@@ -1966,4 +1983,169 @@ impl AnotherTrait<i32> for () {
 "#,
         );
     }
+
+    #[test]
+    fn doc_hidden_default_impls_ignored() {
+        // doc(hidden) attr is ignored trait and impl both belong to the local crate.
+        check_assist(
+            add_missing_default_members,
+            r#"
+struct Foo;
+trait Trait {
+    #[doc(hidden)]
+    fn func_with_default_impl() -> u32 {
+        42
+    }
+    fn another_default_impl() -> u32 {
+        43
+    }
+}
+impl Tra$0it for Foo {}"#,
+            r#"
+struct Foo;
+trait Trait {
+    #[doc(hidden)]
+    fn func_with_default_impl() -> u32 {
+        42
+    }
+    fn another_default_impl() -> u32 {
+        43
+    }
+}
+impl Trait for Foo {
+    $0fn func_with_default_impl() -> u32 {
+        42
+    }
+
+    fn another_default_impl() -> u32 {
+        43
+    }
+}"#,
+        )
+    }
+
+    #[test]
+    fn doc_hidden_default_impls_lang_crates() {
+        // Not applicable because Eq has a single method and this has a #[doc(hidden)] attr set.
+        check_assist_not_applicable(
+            add_missing_default_members,
+            r#"
+//- minicore: eq
+use core::cmp::Eq;
+struct Foo;
+impl E$0q for Foo { /* $0 */ }
+"#,
+        )
+    }
+
+    #[test]
+    fn doc_hidden_default_impls_lib_crates() {
+        check_assist(
+            add_missing_default_members,
+            r#"
+    //- /main.rs crate:a deps:b
+    struct B;
+    impl b::Exte$0rnTrait for B {}
+    //- /lib.rs crate:b new_source_root:library
+    pub trait ExternTrait {
+        #[doc(hidden)]
+        fn hidden_default() -> Option<()> {
+            todo!()
+        }
+
+        fn unhidden_default() -> Option<()> {
+            todo!()
+        }
+
+        fn unhidden_nondefault() -> Option<()>;
+    }
+                "#,
+            r#"
+    struct B;
+    impl b::ExternTrait for B {
+        $0fn unhidden_default() -> Option<()> {
+            todo!()
+        }
+    }
+    "#,
+        )
+    }
+
+    #[test]
+    fn doc_hidden_default_impls_local_crates() {
+        check_assist(
+            add_missing_default_members,
+            r#"
+trait LocalTrait {
+    #[doc(hidden)]
+    fn no_skip_default() -> Option<()> {
+        todo!()
+    }
+    fn no_skip_default_2() -> Option<()> {
+        todo!()
+    }
+}
+
+struct B;
+impl Loc$0alTrait for B {}
+            "#,
+            r#"
+trait LocalTrait {
+    #[doc(hidden)]
+    fn no_skip_default() -> Option<()> {
+        todo!()
+    }
+    fn no_skip_default_2() -> Option<()> {
+        todo!()
+    }
+}
+
+struct B;
+impl LocalTrait for B {
+    $0fn no_skip_default() -> Option<()> {
+        todo!()
+    }
+
+    fn no_skip_default_2() -> Option<()> {
+        todo!()
+    }
+}
+            "#,
+        )
+    }
+
+    #[test]
+    fn doc_hidden_default_impls_workspace_crates() {
+        check_assist(
+            add_missing_default_members,
+            r#"
+//- /lib.rs crate:b new_source_root:local
+trait LocalTrait {
+    #[doc(hidden)]
+    fn no_skip_default() -> Option<()> {
+        todo!()
+    }
+    fn no_skip_default_2() -> Option<()> {
+        todo!()
+    }
+}
+
+//- /main.rs crate:a deps:b
+struct B;
+impl b::Loc$0alTrait for B {}
+            "#,
+            r#"
+struct B;
+impl b::LocalTrait for B {
+    $0fn no_skip_default() -> Option<()> {
+        todo!()
+    }
+
+    fn no_skip_default_2() -> Option<()> {
+        todo!()
+    }
+}
+            "#,
+        )
+    }
 }

crates/ide-assists/src/handlers/replace_derive_with_manual_impl.rs

@@ -10,7 +10,7 @@
     assist_context::{AssistContext, Assists, SourceChangeBuilder},
     utils::{
         add_trait_assoc_items_to_impl, filter_assoc_items, gen_trait_fn_body,
-        generate_trait_impl_text, render_snippet, Cursor, DefaultMethods,
+        generate_trait_impl_text, render_snippet, Cursor, DefaultMethods, IgnoreAssocItems,
     },
     AssistId, AssistKind,
 };
@@ -172,7 +172,17 @@ fn impl_def_from_trait(
 ) -> Option<(ast::Impl, ast::AssocItem)> {
     let trait_ = trait_?;
     let target_scope = sema.scope(annotated_name.syntax())?;
-    let trait_items = filter_assoc_items(sema, &trait_.items(sema.db), DefaultMethods::No);
+
+    // Keep assoc items of local crates even if they have #[doc(hidden)] attr.
+    let ignore_items = if trait_.module(sema.db).krate().origin(sema.db).is_local() {
+        IgnoreAssocItems::No
+    } else {
+        IgnoreAssocItems::DocHiddenAttrPresent
+    };
+
+    let trait_items =
+        filter_assoc_items(sema, &trait_.items(sema.db), DefaultMethods::No, ignore_items);
+
     if trait_items.is_empty() {
         return None;
     }

crates/ide-assists/src/utils.rs

@@ -3,7 +3,7 @@
 use std::ops;
 
 pub(crate) use gen_trait_fn_body::gen_trait_fn_body;
-use hir::{db::HirDatabase, HirDisplay, InFile, Semantics};
+use hir::{db::HirDatabase, HasAttrs as HirHasAttrs, HirDisplay, InFile, Semantics};
 use ide_db::{
     famous_defs::FamousDefs, path_transform::PathTransform,
     syntax_helpers::insert_whitespace_into_node::insert_ws_into, RootDatabase, SnippetCap,
@@ -84,6 +84,12 @@ pub fn test_related_attribute(fn_def: &ast::Fn) -> Option<ast::Attr> {
     })
 }
 
+#[derive(Clone, Copy, PartialEq)]
+pub enum IgnoreAssocItems {
+    DocHiddenAttrPresent,
+    No,
+}
+
 #[derive(Copy, Clone, PartialEq)]
 pub enum DefaultMethods {
     Only,
@@ -94,11 +100,16 @@ pub fn filter_assoc_items(
     sema: &Semantics<'_, RootDatabase>,
     items: &[hir::AssocItem],
     default_methods: DefaultMethods,
+    ignore_items: IgnoreAssocItems,
 ) -> Vec<InFile<ast::AssocItem>> {
     return items
         .iter()
-        // Note: This throws away items with no source.
         .copied()
+        .filter(|assoc_item| {
+            !(ignore_items == IgnoreAssocItems::DocHiddenAttrPresent
+                && assoc_item.attrs(sema.db).has_doc_hidden())
+        })
+        // Note: This throws away items with no source.
         .filter_map(|assoc_item| {
             let item = match assoc_item {
                 hir::AssocItem::Function(it) => sema.source(it)?.map(ast::AssocItem::Fn),