add tests to verify relevance of notable traits and some refactors

crates/ide-completion/src/render.rs

@@ -2443,4 +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

@@ -74,15 +74,13 @@ fn render(
     );
 
     let ret_type = func.ret_type(db);
-    let is_op_method = func
+    let assoc_item = func.as_assoc_item(db);
-        .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 is_item_from_notable_trait = func
+    let trait_ = assoc_item.and_then(|trait_| trait_.containing_trait_or_trait_impl(db));
-        .as_assoc_item(ctx.db())
+    let is_op_method = trait_.map_or(false, |trait_| completion.is_ops_trait(trait_));
-        .and_then(|trait_| trait_.containing_trait(ctx.db()))
+
-        .map_or(false, |trait_| completion.is_doc_notable_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 {
@@ -147,7 +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());
                 }