Add notable_trait predicate to CompletionRelevance

crates/hir-def/src/attr.rs

@@ -207,6 +207,13 @@ impl Attrs {
         })
     }
 
+    pub fn has_doc_notable_trait(&self) -> bool {
+        self.by_key("doc").tt_values().any(|tt| {
+            tt.delimiter.kind == DelimiterKind::Parenthesis &&
+                matches!(&*tt.token_trees, [tt::TokenTree::Leaf(tt::Leaf::Ident(ident))] if ident.text == "notable_trait")
+        })
+    }
+
     pub fn doc_exprs(&self) -> impl Iterator<Item = DocExpr> + '_ {
         self.by_key("doc").tt_values().map(DocExpr::parse)
     }

crates/ide-completion/src/context.rs

@@ -529,6 +529,11 @@ impl CompletionContext<'_> {
         }
     }
 
+    /// Whether the given trait has `#[doc(notable_trait)]`
+    pub(crate) fn is_doc_notable_trait(&self, trait_: hir::Trait) -> bool {
+        trait_.attrs(self.db).has_doc_notable_trait()
+    }
+
     /// Returns the traits in scope, with the [`Drop`] trait removed.
     pub(crate) fn traits_in_scope(&self) -> hir::VisibleTraits {
         let mut traits_in_scope = self.scope.visible_traits();

crates/ide-completion/src/item.rs

@@ -152,6 +152,8 @@ pub struct CompletionRelevance {
     pub is_local: bool,
     /// This is set when trait items are completed in an impl of that trait.
     pub is_item_from_trait: bool,
+    /// This is set for when trait items are from traits with `#[doc(notable_trait)]`
+    pub is_item_from_notable_trait: bool,
     /// This is set when an import is suggested whose name is already imported.
     pub is_name_already_imported: bool,
     /// This is set for completions that will insert a `use` item.
@@ -228,6 +230,7 @@ impl CompletionRelevance {
             is_private_editable,
             postfix_match,
             is_definite,
+            is_item_from_notable_trait,
         } = self;
 
         // lower rank private things
@@ -266,6 +269,9 @@ impl CompletionRelevance {
         if is_item_from_trait {
             score += 1;
         }
+        if is_item_from_notable_trait {
+            score += 1;
+        }
         if is_definite {
             score += 10;
         }

crates/ide-completion/src/render.rs

@@ -1170,6 +1170,7 @@ fn main() { let _: m::Spam = S$0 }
                             ),
                             is_local: false,
                             is_item_from_trait: false,
+                            is_item_from_notable_trait: false,
                             is_name_already_imported: false,
                             requires_import: false,
                             is_op_method: false,
@@ -1196,6 +1197,7 @@ fn main() { let _: m::Spam = S$0 }
                             ),
                             is_local: false,
                             is_item_from_trait: false,
+                            is_item_from_notable_trait: false,
                             is_name_already_imported: false,
                             requires_import: false,
                             is_op_method: false,
@@ -1274,6 +1276,7 @@ fn foo() { A { the$0 } }
                             ),
                             is_local: false,
                             is_item_from_trait: false,
+                            is_item_from_notable_trait: false,
                             is_name_already_imported: false,
                             requires_import: false,
                             is_op_method: false,
@@ -2089,6 +2092,7 @@ fn foo() {
                             ),
                             is_local: false,
                             is_item_from_trait: false,
+                            is_item_from_notable_trait: false,
                             is_name_already_imported: false,
                             requires_import: false,
                             is_op_method: false,
@@ -2439,4 +2443,81 @@ impl S {
 "#,
         )
     }
+
+    #[test]
+    fn notable_traits_method_relevance() {
+        check_kinds(
+            r#"
+#[doc(notable_trait)]
+trait Write {
+    fn write(&self);
+    fn flush(&self);
+}
+
+struct Writer;
+
+impl Write for Writer {
+    fn write(&self) {}
+    fn flush(&self) {}
+}
+
+fn main() {
+    Writer.$0
+}
+"#,
+            &[
+                CompletionItemKind::Method,
+                CompletionItemKind::SymbolKind(SymbolKind::Field),
+                CompletionItemKind::SymbolKind(SymbolKind::Function),
+            ],
+            expect![[r#"
+                [
+                    CompletionItem {
+                        label: "flush()",
+                        source_range: 193..193,
+                        delete: 193..193,
+                        insert: "flush()$0",
+                        kind: Method,
+                        lookup: "flush",
+                        detail: "fn(&self)",
+                        relevance: CompletionRelevance {
+                            exact_name_match: false,
+                            type_match: None,
+                            is_local: false,
+                            is_item_from_trait: false,
+                            is_item_from_notable_trait: true,
+                            is_name_already_imported: false,
+                            requires_import: false,
+                            is_op_method: false,
+                            is_private_editable: false,
+                            postfix_match: None,
+                            is_definite: false,
+                        },
+                    },
+                    CompletionItem {
+                        label: "write()",
+                        source_range: 193..193,
+                        delete: 193..193,
+                        insert: "write()$0",
+                        kind: Method,
+                        lookup: "write",
+                        detail: "fn(&self)",
+                        relevance: CompletionRelevance {
+                            exact_name_match: false,
+                            type_match: None,
+                            is_local: false,
+                            is_item_from_trait: false,
+                            is_item_from_notable_trait: true,
+                            is_name_already_imported: false,
+                            requires_import: false,
+                            is_op_method: false,
+                            is_private_editable: false,
+                            postfix_match: None,
+                            is_definite: false,
+                        },
+                    },
+                ]
+            "#]],
+        );
+    }
 }

crates/ide-completion/src/render/function.rs

@@ -74,10 +74,13 @@ fn render(
     );
 
     let ret_type = func.ret_type(db);
-    let is_op_method = func
-        .as_assoc_item(ctx.db())
-        .and_then(|trait_| trait_.containing_trait_or_trait_impl(ctx.db()))
-        .map_or(false, |trait_| completion.is_ops_trait(trait_));
+    let assoc_item = func.as_assoc_item(db);
+
+    let trait_ = assoc_item.and_then(|trait_| trait_.containing_trait_or_trait_impl(db));
+    let is_op_method = trait_.map_or(false, |trait_| completion.is_ops_trait(trait_));
+
+    let is_item_from_notable_trait =
+        trait_.map_or(false, |trait_| completion.is_doc_notable_trait(trait_));
 
     let (has_dot_receiver, has_call_parens, cap) = match func_kind {
         FuncKind::Function(&PathCompletionCtx {
@@ -105,6 +108,7 @@ fn render(
         },
         exact_name_match: compute_exact_name_match(completion, &call),
         is_op_method,
+        is_item_from_notable_trait,
         ..ctx.completion_relevance()
     });
 
@@ -141,7 +145,7 @@ fn render(
             item.add_import(import_to_add);
         }
         None => {
-            if let Some(actm) = func.as_assoc_item(db) {
+            if let Some(actm) = assoc_item {
                 if let Some(trt) = actm.containing_trait_or_trait_impl(db) {
                     item.trait_name(trt.name(db).to_smol_str());
                 }