diff options
| -rw-r--r-- | clippy_lints/src/let_underscore.rs | 15 | ||||
| -rw-r--r-- | tests/ui/let_underscore_untyped.rs | 5 | ||||
| -rw-r--r-- | tests/ui/let_underscore_untyped.stderr | 20 |
3 files changed, 24 insertions, 16 deletions
diff --git a/clippy_lints/src/let_underscore.rs b/clippy_lints/src/let_underscore.rs index 51b5de27de8..637b7de920e 100644 --- a/clippy_lints/src/let_underscore.rs +++ b/clippy_lints/src/let_underscore.rs @@ -1,7 +1,7 @@ use clippy_utils::diagnostics::span_lint_and_help; use clippy_utils::ty::{implements_trait, is_must_use_ty, match_type}; use clippy_utils::{is_must_use_func_call, paths}; -use rustc_hir::{Local, PatKind}; +use rustc_hir::{ExprKind, Local, PatKind}; use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::lint::in_external_macro; use rustc_middle::ty::subst::GenericArgKind; @@ -189,7 +189,18 @@ 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. - span_lint_and_help( + + // 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; + } + } + + + span_lint_and_help( cx, LET_UNDERSCORE_UNTYPED, local.span, diff --git a/tests/ui/let_underscore_untyped.rs b/tests/ui/let_underscore_untyped.rs index bcb33c5c7e3..8486137d3a6 100644 --- a/tests/ui/let_underscore_untyped.rs +++ b/tests/ui/let_underscore_untyped.rs @@ -28,6 +28,10 @@ fn f() -> Box<dyn Display> { Box::new(1) } +fn g() -> impl Fn() { + || {} +} + fn main() { let _ = a(); let _ = b(1); @@ -35,6 +39,7 @@ fn main() { let _ = d(&1); let _ = e(); let _ = f(); + let _ = g(); _ = a(); _ = b(1); diff --git a/tests/ui/let_underscore_untyped.stderr b/tests/ui/let_underscore_untyped.stderr index 36c3d1214d6..47e76ea1d04 100644 --- a/tests/ui/let_underscore_untyped.stderr +++ b/tests/ui/let_underscore_untyped.stderr @@ -1,5 +1,5 @@ error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:32:5 + --> $DIR/let_underscore_untyped.rs:36:5 | LL | let _ = a(); | ^^^^^^^^^^^^ @@ -8,7 +8,7 @@ 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:33:5 + --> $DIR/let_underscore_untyped.rs:37:5 | LL | let _ = b(1); | ^^^^^^^^^^^^^ @@ -16,15 +16,7 @@ LL | let _ = b(1); = help: consider adding a type annotation or removing the `let` keyword error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:34:5 - | -LL | let _ = c(); - | ^^^^^^^^^^^^ - | - = help: consider adding a type annotation or removing the `let` keyword - -error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:35:5 + --> $DIR/let_underscore_untyped.rs:39:5 | LL | let _ = d(&1); | ^^^^^^^^^^^^^^ @@ -32,7 +24,7 @@ LL | let _ = d(&1); = help: consider adding a type annotation or removing the `let` keyword error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:36:5 + --> $DIR/let_underscore_untyped.rs:40:5 | LL | let _ = e(); | ^^^^^^^^^^^^ @@ -40,12 +32,12 @@ LL | let _ = e(); = help: consider adding a type annotation or removing the `let` keyword error: non-binding `let` without a type annotation - --> $DIR/let_underscore_untyped.rs:37:5 + --> $DIR/let_underscore_untyped.rs:41:5 | LL | let _ = f(); | ^^^^^^^^^^^^ | = help: consider adding a type annotation or removing the `let` keyword -error: aborting due to 6 previous errors +error: aborting due to 5 previous errors |