diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs index 1a5515530ae..045d76cac62 100644 --- a/compiler/rustc_lint/src/unused.rs +++ b/compiler/rustc_lint/src/unused.rs @@ -95,10 +95,17 @@ fn check_stmt(&mut self, cx: &LateContext<'_>, s: &hir::Stmt<'_>) { if let hir::ExprKind::Match(await_expr, _arms, hir::MatchSource::AwaitDesugar) = expr.kind && let ty = cx.typeck_results().expr_ty(&await_expr) - && let ty::Opaque(def_id, _) = ty.kind() + && let ty::Opaque(future_def_id, _) = ty.kind() && cx.tcx.ty_is_opaque_future(ty) - && let parent = cx.tcx.parent(*def_id) - && check_must_use_def(cx, parent, expr.span, "awaited future returned by ", "") + // FIXME: This also includes non-async fns that return `impl Future`. + && let async_fn_def_id = cx.tcx.parent(*future_def_id) + && check_must_use_def( + cx, + async_fn_def_id, + expr.span, + "output of future returned by ", + "", + ) { // We have a bare `foo().await;` on an opaque type from an async function that was // annotated with `#[must_use]`. diff --git a/src/test/ui/lint/unused/unused-async.rs b/src/test/ui/lint/unused/unused-async.rs index eda28dab27f..4be93aa155a 100644 --- a/src/test/ui/lint/unused/unused-async.rs +++ b/src/test/ui/lint/unused/unused-async.rs @@ -30,10 +30,10 @@ async fn test_method() -> i32 { async fn test() { foo(); //~ ERROR unused return value of `foo` that must be used //~^ ERROR unused implementer of `Future` that must be used - foo().await; //~ ERROR unused awaited future returned by `foo` that must be used + foo().await; //~ ERROR unused output of future returned by `foo` that must be used bar(); //~ ERROR unused return value of `bar` that must be used //~^ ERROR unused implementer of `Future` that must be used - bar().await; //~ ERROR unused awaited future returned by `bar` that must be used + bar().await; //~ ERROR unused output of future returned by `bar` that must be used baz(); //~ ERROR unused implementer of `Future` that must be used baz().await; // ok } diff --git a/src/test/ui/lint/unused/unused-async.stderr b/src/test/ui/lint/unused/unused-async.stderr index ae284681720..abc49599309 100644 --- a/src/test/ui/lint/unused/unused-async.stderr +++ b/src/test/ui/lint/unused/unused-async.stderr @@ -17,7 +17,7 @@ error: unused return value of `foo` that must be used LL | foo(); | ^^^^^ -error: unused awaited future returned by `foo` that must be used +error: unused output of future returned by `foo` that must be used --> $DIR/unused-async.rs:33:5 | LL | foo().await; @@ -37,7 +37,7 @@ error: unused return value of `bar` that must be used LL | bar(); | ^^^^^ -error: unused awaited future returned by `bar` that must be used +error: unused output of future returned by `bar` that must be used --> $DIR/unused-async.rs:36:5 | LL | bar().await;