From 5336f88403aae270e1e8bbf0aee31707311c590f Mon Sep 17 00:00:00 2001 From: xFrednet Date: Tue, 8 Jun 2021 00:14:43 +0200 Subject: [PATCH] Move `map_identity` into the `methods` module --- clippy_lints/src/lib.rs | 8 +-- clippy_lints/src/map_identity.rs | 76 ------------------------ clippy_lints/src/methods/map_identity.rs | 38 ++++++++++++ clippy_lints/src/methods/mod.rs | 26 ++++++++ 4 files changed, 67 insertions(+), 81 deletions(-) delete mode 100644 clippy_lints/src/map_identity.rs create mode 100644 clippy_lints/src/methods/map_identity.rs diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index e7dd3952b3a..c6d9b378603 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -254,7 +254,6 @@ mod manual_strip; mod manual_unwrap_or; mod map_clone; mod map_err_ignore; -mod map_identity; mod map_unit_fn; mod match_on_vec_items; mod matches; @@ -705,7 +704,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: manual_unwrap_or::MANUAL_UNWRAP_OR, map_clone::MAP_CLONE, map_err_ignore::MAP_ERR_IGNORE, - map_identity::MAP_IDENTITY, map_unit_fn::OPTION_MAP_UNIT_FN, map_unit_fn::RESULT_MAP_UNIT_FN, match_on_vec_items::MATCH_ON_VEC_ITEMS, @@ -765,6 +763,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: methods::MANUAL_STR_REPEAT, methods::MAP_COLLECT_RESULT_UNIT, methods::MAP_FLATTEN, + methods::MAP_IDENTITY, methods::MAP_UNWRAP_OR, methods::NEW_RET_NO_SELF, methods::OK_EXPECT, @@ -1260,7 +1259,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(manual_strip::MANUAL_STRIP), LintId::of(manual_unwrap_or::MANUAL_UNWRAP_OR), LintId::of(map_clone::MAP_CLONE), - LintId::of(map_identity::MAP_IDENTITY), LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN), LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN), LintId::of(matches::INFALLIBLE_DESTRUCTURING_MATCH), @@ -1301,6 +1299,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(methods::MANUAL_SATURATING_ARITHMETIC), LintId::of(methods::MANUAL_STR_REPEAT), LintId::of(methods::MAP_COLLECT_RESULT_UNIT), + LintId::of(methods::MAP_IDENTITY), LintId::of(methods::NEW_RET_NO_SELF), LintId::of(methods::OK_EXPECT), LintId::of(methods::OPTION_AS_REF_DEREF), @@ -1586,7 +1585,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(loops::WHILE_LET_LOOP), LintId::of(manual_strip::MANUAL_STRIP), LintId::of(manual_unwrap_or::MANUAL_UNWRAP_OR), - LintId::of(map_identity::MAP_IDENTITY), LintId::of(map_unit_fn::OPTION_MAP_UNIT_FN), LintId::of(map_unit_fn::RESULT_MAP_UNIT_FN), LintId::of(matches::MATCH_AS_REF), @@ -1601,6 +1599,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(methods::ITER_COUNT), LintId::of(methods::MANUAL_FILTER_MAP), LintId::of(methods::MANUAL_FIND_MAP), + LintId::of(methods::MAP_IDENTITY), LintId::of(methods::OPTION_AS_REF_DEREF), LintId::of(methods::OPTION_FILTER_MAP), LintId::of(methods::SEARCH_IS_SOME), @@ -2039,7 +2038,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: single_char_binding_names_threshold, }); store.register_late_pass(|| box macro_use::MacroUseImports::default()); - store.register_late_pass(|| box map_identity::MapIdentity); store.register_late_pass(|| box pattern_type_mismatch::PatternTypeMismatch); store.register_late_pass(|| box stable_sort_primitive::StableSortPrimitive); store.register_late_pass(|| box repeat_once::RepeatOnce); diff --git a/clippy_lints/src/map_identity.rs b/clippy_lints/src/map_identity.rs deleted file mode 100644 index 9bcb010ff6d..00000000000 --- a/clippy_lints/src/map_identity.rs +++ /dev/null @@ -1,76 +0,0 @@ -use clippy_utils::diagnostics::span_lint_and_sugg; -use clippy_utils::ty::is_type_diagnostic_item; -use clippy_utils::{is_expr_identity_function, is_trait_method}; -use if_chain::if_chain; -use rustc_errors::Applicability; -use rustc_hir::{Expr, ExprKind}; -use rustc_lint::{LateContext, LateLintPass}; -use rustc_session::{declare_lint_pass, declare_tool_lint}; -use rustc_span::sym; - -declare_clippy_lint! { - /// **What it does:** Checks for instances of `map(f)` where `f` is the identity function. - /// - /// **Why is this bad?** It can be written more concisely without the call to `map`. - /// - /// **Known problems:** None. - /// - /// **Example:** - /// - /// ```rust - /// let x = [1, 2, 3]; - /// let y: Vec<_> = x.iter().map(|x| x).map(|x| 2*x).collect(); - /// ``` - /// Use instead: - /// ```rust - /// let x = [1, 2, 3]; - /// let y: Vec<_> = x.iter().map(|x| 2*x).collect(); - /// ``` - pub MAP_IDENTITY, - complexity, - "using iterator.map(|x| x)" -} - -declare_lint_pass!(MapIdentity => [MAP_IDENTITY]); - -impl<'tcx> LateLintPass<'tcx> for MapIdentity { - fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { - if expr.span.from_expansion() { - return; - } - - if_chain! { - if let Some([caller, func]) = get_map_argument(cx, expr); - if is_expr_identity_function(cx, func); - then { - span_lint_and_sugg( - cx, - MAP_IDENTITY, - expr.span.trim_start(caller.span).unwrap(), - "unnecessary map of the identity function", - "remove the call to `map`", - String::new(), - Applicability::MachineApplicable - ) - } - } - } -} - -/// Returns the arguments passed into map() if the expression is a method call to -/// map(). Otherwise, returns None. -fn get_map_argument<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<&'a [Expr<'a>]> { - if_chain! { - if let ExprKind::MethodCall(method, _, args, _) = expr.kind; - if args.len() == 2 && method.ident.name == sym::map; - let caller_ty = cx.typeck_results().expr_ty(&args[0]); - if is_trait_method(cx, expr, sym::Iterator) - || is_type_diagnostic_item(cx, caller_ty, sym::result_type) - || is_type_diagnostic_item(cx, caller_ty, sym::option_type); - then { - Some(args) - } else { - None - } - } -} diff --git a/clippy_lints/src/methods/map_identity.rs b/clippy_lints/src/methods/map_identity.rs new file mode 100644 index 00000000000..538a12566e3 --- /dev/null +++ b/clippy_lints/src/methods/map_identity.rs @@ -0,0 +1,38 @@ +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::ty::is_type_diagnostic_item; +use clippy_utils::{is_expr_identity_function, is_trait_method}; +use rustc_errors::Applicability; +use rustc_hir as hir; +use rustc_lint::LateContext; +use rustc_span::{source_map::Span, sym}; + +use super::MAP_IDENTITY; + +pub(super) fn check( + cx: &LateContext<'_>, + expr: &hir::Expr<'_>, + caller: &hir::Expr<'_>, + map_arg: &hir::Expr<'_>, + _map_span: Span, +) { + let caller_ty = cx.typeck_results().expr_ty(caller); + + if_chain! { + if is_trait_method(cx, expr, sym::Iterator) + || is_type_diagnostic_item(cx, caller_ty, sym::result_type) + || is_type_diagnostic_item(cx, caller_ty, sym::option_type); + if is_expr_identity_function(cx, map_arg); + if let Some(sugg_span) = expr.span.trim_start(caller.span); + then { + span_lint_and_sugg( + cx, + MAP_IDENTITY, + sugg_span, + "unnecessary map of the identity function", + "remove the call to `map`", + String::new(), + Applicability::MachineApplicable, + ) + } + } +} diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index c8ae972f18c..d4f8cef4f37 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -35,6 +35,7 @@ mod manual_saturating_arithmetic; mod manual_str_repeat; mod map_collect_result_unit; mod map_flatten; +mod map_identity; mod map_unwrap_or; mod ok_expect; mod option_as_ref_deref; @@ -1561,6 +1562,29 @@ declare_clippy_lint! { "call to `filter_map` where `flatten` is sufficient" } +declare_clippy_lint! { + /// **What it does:** Checks for instances of `map(f)` where `f` is the identity function. + /// + /// **Why is this bad?** It can be written more concisely without the call to `map`. + /// + /// **Known problems:** None. + /// + /// **Example:** + /// + /// ```rust + /// let x = [1, 2, 3]; + /// let y: Vec<_> = x.iter().map(|x| x).map(|x| 2*x).collect(); + /// ``` + /// Use instead: + /// ```rust + /// let x = [1, 2, 3]; + /// let y: Vec<_> = x.iter().map(|x| 2*x).collect(); + /// ``` + pub MAP_IDENTITY, + complexity, + "using iterator.map(|x| x)" +} + declare_clippy_lint! { /// **What it does:** Checks for the use of `.bytes().nth()`. /// @@ -1728,6 +1752,7 @@ impl_lint_pass!(Methods => [ FILTER_NEXT, SKIP_WHILE_NEXT, FILTER_MAP_IDENTITY, + MAP_IDENTITY, MANUAL_FILTER_MAP, MANUAL_FIND_MAP, OPTION_FILTER_MAP, @@ -2058,6 +2083,7 @@ fn check_methods<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, msrv: Optio _ => {}, } } + map_identity::check(cx, expr, recv, m_arg, span); }, ("map_or", [def, map]) => option_map_or_none::check(cx, expr, recv, def, map), ("next", []) => {