diff --git a/clippy_lints/src/let_underscore.rs b/clippy_lints/src/let_underscore.rs index 16772a9d598..20a675d053e 100644 --- a/clippy_lints/src/let_underscore.rs +++ b/clippy_lints/src/let_underscore.rs @@ -1,4 +1,5 @@ use clippy_utils::diagnostics::span_lint_and_help; +use clippy_utils::is_from_proc_macro; use clippy_utils::ty::{implements_trait, is_must_use_ty, match_type}; use clippy_utils::{is_must_use_func_call, paths}; use rustc_hir::{ExprKind, Local, PatKind}; @@ -138,7 +139,7 @@ const SYNC_GUARD_PATHS: [&[&str]; 3] = [ ]; impl<'tcx> LateLintPass<'tcx> for LetUnderscore { - fn check_local(&mut self, cx: &LateContext<'_>, local: &Local<'_>) { + fn check_local(&mut self, cx: &LateContext<'tcx>, local: &Local<'tcx>) { if !in_external_macro(cx.tcx.sess, local.span) && let PatKind::Wild = local.pat.kind && let Some(init) = local.init @@ -191,15 +192,20 @@ impl<'tcx> LateLintPass<'tcx> for LetUnderscore { if local.pat.default_binding_modes && local.ty.is_none() { // When `default_binding_modes` is true, the `let` keyword is present. - // Ignore function calls that return impl traits... - if let Some(init) = local.init && - matches!(init.kind, ExprKind::Call(_, _) | ExprKind::MethodCall(_, _, _, _)) { - let expr_ty = cx.typeck_results().expr_ty(init); - if expr_ty.is_impl_trait() { - return; - } - } - + if let Some(init) = local.init { + // Ignore function calls that return impl traits... + if matches!(init.kind, ExprKind::Call(_, _) | ExprKind::MethodCall(_, _, _, _)) { + let expr_ty = cx.typeck_results().expr_ty(init); + if expr_ty.is_impl_trait() { + return; + } + } + + // Ignore if it is from a procedural macro... + if is_from_proc_macro(cx, init) { + return; + } + } span_lint_and_help( cx, diff --git a/tests/ui/let_underscore_untyped.rs b/tests/ui/let_underscore_untyped.rs index 8486137d3a6..05ecd9b281a 100644 --- a/tests/ui/let_underscore_untyped.rs +++ b/tests/ui/let_underscore_untyped.rs @@ -1,6 +1,12 @@ +//@aux-build: proc_macros.rs + #![allow(unused)] #![warn(clippy::let_underscore_untyped)] +extern crate proc_macros; +use proc_macros::with_span; + +use clippy_utils::is_from_proc_macro; use std::future::Future; use std::{boxed::Box, fmt::Display}; @@ -32,6 +38,14 @@ fn g() -> impl Fn() { || {} } +with_span!( + span + + fn dont_lint_proc_macro() { + let _ = a(); + } +); + fn main() { let _ = a(); let _ = b(1); diff --git a/tests/ui/let_underscore_untyped.stderr b/tests/ui/let_underscore_untyped.stderr index 6844cb998f7..bbf2508af10 100644 --- a/tests/ui/let_underscore_untyped.stderr +++ b/tests/ui/let_underscore_untyped.stderr @@ -1,60 +1,60 @@ error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:36:5 + --> $DIR/let_underscore_untyped.rs:50:5 | LL | let _ = a(); | ^^^^^^^^^^^^ | help: consider adding a type annotation - --> $DIR/let_underscore_untyped.rs:36:10 + --> $DIR/let_underscore_untyped.rs:50:10 | LL | let _ = a(); | ^ = note: `-D clippy::let-underscore-untyped` implied by `-D warnings` error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:37:5 + --> $DIR/let_underscore_untyped.rs:51:5 | LL | let _ = b(1); | ^^^^^^^^^^^^^ | help: consider adding a type annotation - --> $DIR/let_underscore_untyped.rs:37:10 + --> $DIR/let_underscore_untyped.rs:51:10 | LL | let _ = b(1); | ^ error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:39:5 + --> $DIR/let_underscore_untyped.rs:53:5 | LL | let _ = d(&1); | ^^^^^^^^^^^^^^ | help: consider adding a type annotation - --> $DIR/let_underscore_untyped.rs:39:10 + --> $DIR/let_underscore_untyped.rs:53:10 | LL | let _ = d(&1); | ^ error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:40:5 + --> $DIR/let_underscore_untyped.rs:54:5 | LL | let _ = e(); | ^^^^^^^^^^^^ | help: consider adding a type annotation - --> $DIR/let_underscore_untyped.rs:40:10 + --> $DIR/let_underscore_untyped.rs:54:10 | LL | let _ = e(); | ^ error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:41:5 + --> $DIR/let_underscore_untyped.rs:55:5 | LL | let _ = f(); | ^^^^^^^^^^^^ | help: consider adding a type annotation - --> $DIR/let_underscore_untyped.rs:41:10 + --> $DIR/let_underscore_untyped.rs:55:10 | LL | let _ = f(); | ^