Simplify the procedure

fix: remove unused import

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

@@ -1,14 +1,12 @@
-use hir::AssocItem;
 use ide_db::{
     assists::{AssistId, AssistKind},
     base_db::FileId,
     defs::Definition,
     search::FileReference,
     syntax_helpers::node_ext::full_path_of_name_ref,
-    traits::resolve_target_trait,
 };
 use syntax::{
-    ast::{self, HasName, NameLike, NameRef},
+    ast::{self, NameLike, NameRef},
     AstNode, SyntaxKind, TextRange,
 };
 
@@ -46,16 +44,13 @@ pub(crate) fn unnecessary_async(acc: &mut Assists, ctx: &AssistContext<'_>) -> O
     if function.body()?.syntax().descendants().find_map(ast::AwaitExpr::cast).is_some() {
         return None;
     }
-    // Do nothing if the method is an async member of trait.
-    if let Some(fname) = function.name() {
-        if let Some(trait_item) = find_corresponding_trait_member(ctx, fname.to_string()) {
-            if let AssocItem::Function(method) = trait_item {
-                if method.is_async(ctx.db()) {
-                    return None;
-                }
-            }
+    // Do nothing if the method is a member of trait.
+    if let Some(impl_) = function.syntax().ancestors().nth(2).and_then(ast::Impl::cast) {
+        if let Some(_) = impl_.trait_() {
+            return None;
         }
     }
+
     // Remove the `async` keyword plus whitespace after it, if any.
     let async_range = {
         let async_token = function.async_token()?;
@@ -99,23 +94,6 @@ pub(crate) fn unnecessary_async(acc: &mut Assists, ctx: &AssistContext<'_>) -> O
     )
 }
 
-fn find_corresponding_trait_member(
-    ctx: &AssistContext<'_>,
-    function_name: String,
-) -> Option<AssocItem> {
-    let impl_ = ctx.find_node_at_offset::<ast::Impl>()?;
-    let trait_ = resolve_target_trait(&ctx.sema, &impl_)?;
-
-    trait_
-        .items(ctx.db())
-        .iter()
-        .find(|item| match item.name(ctx.db()) {
-            Some(method_name) => method_name.to_string() == function_name,
-            _ => false,
-        })
-        .cloned()
-}
-
 fn find_all_references(
     ctx: &AssistContext<'_>,
     def: &Definition,
@@ -283,27 +261,6 @@ pub async fn f(s: &S) { s.f2() }"#,
         check_assist_not_applicable(unnecessary_async, "pub async fn f() { $0f2() }")
     }
 
-    #[test]
-    fn applies_on_unnecessary_async_on_trait_method() {
-        check_assist(
-            unnecessary_async,
-            r#"
-trait Trait {
-    fn foo();
-}
-impl Trait for () {
-    $0async fn foo() {}
-}"#,
-            r#"
-trait Trait {
-    fn foo();
-}
-impl Trait for () {
-    fn foo() {}
-}"#,
-        );
-    }
-
     #[test]
     fn does_not_apply_on_async_trait_method() {
         check_assist_not_applicable(