From 21ddc50eec995332e45c457250539c74bc55015c Mon Sep 17 00:00:00 2001 From: Ada Alakbarova Date: Fri, 7 Nov 2025 22:13:12 +0100 Subject: [PATCH] chore(unnecessary_map_on_constructor): clean-up - reduce indentation - print constructor/method name in backticks --- .../src/unnecessary_map_on_constructor.rs | 52 ++++++++----------- .../ui/unnecessary_map_on_constructor.stderr | 16 +++--- 2 files changed, 30 insertions(+), 38 deletions(-) diff --git a/clippy_lints/src/unnecessary_map_on_constructor.rs b/clippy_lints/src/unnecessary_map_on_constructor.rs index af9f291f5deb..fba530d0dfca 100644 --- a/clippy_lints/src/unnecessary_map_on_constructor.rs +++ b/clippy_lints/src/unnecessary_map_on_constructor.rs @@ -35,18 +35,17 @@ declare_lint_pass!(UnnecessaryMapOnConstructor => [UNNECESSARY_MAP_ON_CONSTRUCTO impl<'tcx> LateLintPass<'tcx> for UnnecessaryMapOnConstructor { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) { - if expr.span.from_expansion() { - return; - } - if let hir::ExprKind::MethodCall(path, recv, [map_arg], ..) = expr.kind + if !expr.span.from_expansion() + && let hir::ExprKind::MethodCall(path, recv, [map_arg], ..) = expr.kind + && !map_arg.span.from_expansion() + && let hir::ExprKind::Path(fun) = map_arg.kind && let Some(sym::Option | sym::Result) = cx.typeck_results().expr_ty(recv).opt_diag_name(cx) { let (constructor_path, constructor_item) = if let hir::ExprKind::Call(constructor, [arg, ..]) = recv.kind && let hir::ExprKind::Path(constructor_path) = constructor.kind + && !constructor.span.from_expansion() + && !arg.span.from_expansion() { - if constructor.span.from_expansion() || arg.span.from_expansion() { - return; - } (constructor_path, arg) } else { return; @@ -67,29 +66,22 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryMapOnConstructor { _ => return, } - if let hir::ExprKind::Path(fun) = map_arg.kind { - if map_arg.span.from_expansion() { - return; - } - let mut applicability = Applicability::MachineApplicable; - let fun_snippet = snippet_with_applicability(cx, fun.span(), "_", &mut applicability); - let constructor_snippet = - snippet_with_applicability(cx, constructor_path.span(), "_", &mut applicability); - let constructor_arg_snippet = - snippet_with_applicability(cx, constructor_item.span, "_", &mut applicability); - span_lint_and_sugg( - cx, - UNNECESSARY_MAP_ON_CONSTRUCTOR, - expr.span, - format!( - "unnecessary {} on constructor {constructor_snippet}(_)", - path.ident.name - ), - "try", - format!("{constructor_snippet}({fun_snippet}({constructor_arg_snippet}))"), - applicability, - ); - } + let mut app = Applicability::MachineApplicable; + let fun_snippet = snippet_with_applicability(cx, fun.span(), "_", &mut app); + let constructor_snippet = snippet_with_applicability(cx, constructor_path.span(), "_", &mut app); + let constructor_arg_snippet = snippet_with_applicability(cx, constructor_item.span, "_", &mut app); + span_lint_and_sugg( + cx, + UNNECESSARY_MAP_ON_CONSTRUCTOR, + expr.span, + format!( + "unnecessary `{}` on constructor `{constructor_snippet}(_)`", + path.ident.name + ), + "try", + format!("{constructor_snippet}({fun_snippet}({constructor_arg_snippet}))"), + app, + ); } } } diff --git a/tests/ui/unnecessary_map_on_constructor.stderr b/tests/ui/unnecessary_map_on_constructor.stderr index f29bfec60f72..a19116820808 100644 --- a/tests/ui/unnecessary_map_on_constructor.stderr +++ b/tests/ui/unnecessary_map_on_constructor.stderr @@ -1,4 +1,4 @@ -error: unnecessary map on constructor Some(_) +error: unnecessary `map` on constructor `Some(_)` --> tests/ui/unnecessary_map_on_constructor.rs:32:13 | LL | let a = Some(x).map(fun); @@ -7,43 +7,43 @@ LL | let a = Some(x).map(fun); = note: `-D clippy::unnecessary-map-on-constructor` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::unnecessary_map_on_constructor)]` -error: unnecessary map on constructor Ok(_) +error: unnecessary `map` on constructor `Ok(_)` --> tests/ui/unnecessary_map_on_constructor.rs:34:27 | LL | let b: SimpleResult = Ok(x).map(fun); | ^^^^^^^^^^^^^^ help: try: `Ok(fun(x))` -error: unnecessary map_err on constructor Err(_) +error: unnecessary `map_err` on constructor `Err(_)` --> tests/ui/unnecessary_map_on_constructor.rs:36:27 | LL | let c: SimpleResult = Err(err).map_err(notfun); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Err(notfun(err))` -error: unnecessary map on constructor Option::Some(_) +error: unnecessary `map` on constructor `Option::Some(_)` --> tests/ui/unnecessary_map_on_constructor.rs:39:13 | LL | let a = Option::Some(x).map(fun); | ^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Option::Some(fun(x))` -error: unnecessary map on constructor SimpleResult::Ok(_) +error: unnecessary `map` on constructor `SimpleResult::Ok(_)` --> tests/ui/unnecessary_map_on_constructor.rs:41:27 | LL | let b: SimpleResult = SimpleResult::Ok(x).map(fun); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `SimpleResult::Ok(fun(x))` -error: unnecessary map_err on constructor SimpleResult::Err(_) +error: unnecessary `map_err` on constructor `SimpleResult::Err(_)` --> tests/ui/unnecessary_map_on_constructor.rs:43:27 | LL | let c: SimpleResult = SimpleResult::Err(err).map_err(notfun); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `SimpleResult::Err(notfun(err))` -error: unnecessary map on constructor Ok(_) +error: unnecessary `map` on constructor `Ok(_)` --> tests/ui/unnecessary_map_on_constructor.rs:45:52 | LL | let b: std::result::Result = Ok(x).map(fun); | ^^^^^^^^^^^^^^ help: try: `Ok(fun(x))` -error: unnecessary map_err on constructor Err(_) +error: unnecessary `map_err` on constructor `Err(_)` --> tests/ui/unnecessary_map_on_constructor.rs:47:52 | LL | let c: std::result::Result = Err(err).map_err(notfun);