diff options
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs')
| -rw-r--r-- | src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs | 82 |
1 files changed, 28 insertions, 54 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs b/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs index bafa6fc58..1cef6226a 100644 --- a/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs +++ b/src/tools/clippy/clippy_lints/src/methods/unnecessary_filter_map.rs @@ -2,9 +2,10 @@ use super::utils::clone_or_copy_needed; use clippy_utils::diagnostics::span_lint; use clippy_utils::ty::is_copy; use clippy_utils::usage::mutated_variables; -use clippy_utils::{is_lang_ctor, is_trait_method, path_to_local_id}; +use clippy_utils::visitors::{for_each_expr, Descend}; +use clippy_utils::{is_res_lang_ctor, is_trait_method, path_res, path_to_local_id}; +use core::ops::ControlFlow; use rustc_hir as hir; -use rustc_hir::intravisit::{walk_expr, Visitor}; use rustc_hir::LangItem::{OptionNone, OptionSome}; use rustc_lint::LateContext; use rustc_middle::ty; @@ -13,7 +14,7 @@ use rustc_span::sym; use super::UNNECESSARY_FILTER_MAP; use super::UNNECESSARY_FIND_MAP; -pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>, name: &str) { +pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'tcx>, arg: &'tcx hir::Expr<'tcx>, name: &str) { if !is_trait_method(cx, expr, sym::Iterator) { return; } @@ -21,22 +22,27 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr< if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = arg.kind { let body = cx.tcx.hir().body(body); let arg_id = body.params[0].pat.hir_id; - let mutates_arg = - mutated_variables(&body.value, cx).map_or(true, |used_mutably| used_mutably.contains(&arg_id)); - let (clone_or_copy_needed, _) = clone_or_copy_needed(cx, body.params[0].pat, &body.value); + let mutates_arg = mutated_variables(body.value, cx).map_or(true, |used_mutably| used_mutably.contains(&arg_id)); + let (clone_or_copy_needed, _) = clone_or_copy_needed(cx, body.params[0].pat, body.value); - let (mut found_mapping, mut found_filtering) = check_expression(cx, arg_id, &body.value); + let (mut found_mapping, mut found_filtering) = check_expression(cx, arg_id, body.value); - let mut return_visitor = ReturnVisitor::new(cx, arg_id); - return_visitor.visit_expr(&body.value); - found_mapping |= return_visitor.found_mapping; - found_filtering |= return_visitor.found_filtering; + let _: Option<!> = for_each_expr(body.value, |e| { + if let hir::ExprKind::Ret(Some(e)) = &e.kind { + let (found_mapping_res, found_filtering_res) = check_expression(cx, arg_id, e); + found_mapping |= found_mapping_res; + found_filtering |= found_filtering_res; + ControlFlow::Continue(Descend::No) + } else { + ControlFlow::Continue(Descend::Yes) + } + }); let in_ty = cx.typeck_results().node_type(body.params[0].hir_id); let sugg = if !found_filtering { if name == "filter_map" { "map" } else { "map(..).next()" } } else if !found_mapping && !mutates_arg && (!clone_or_copy_needed || is_copy(cx, in_ty)) { - match cx.typeck_results().expr_ty(&body.value).kind() { + match cx.typeck_results().expr_ty(body.value).kind() { ty::Adt(adt, subst) if cx.tcx.is_diagnostic_item(sym::Option, adt.did()) && in_ty == subst.type_at(0) => { @@ -55,22 +61,20 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr< UNNECESSARY_FIND_MAP }, expr.span, - &format!("this `.{}` can be written more simply using `.{}`", name, sugg), + &format!("this `.{name}` can be written more simply using `.{sugg}`"), ); } } // returns (found_mapping, found_filtering) fn check_expression<'tcx>(cx: &LateContext<'tcx>, arg_id: hir::HirId, expr: &'tcx hir::Expr<'_>) -> (bool, bool) { - match &expr.kind { + match expr.kind { hir::ExprKind::Call(func, args) => { - if let hir::ExprKind::Path(ref path) = func.kind { - if is_lang_ctor(cx, path, OptionSome) { - if path_to_local_id(&args[0], arg_id) { - return (false, false); - } - return (true, false); + if is_res_lang_ctor(cx, path_res(cx, func), OptionSome) { + if path_to_local_id(&args[0], arg_id) { + return (false, false); } + return (true, false); } (true, true) }, @@ -81,7 +85,7 @@ fn check_expression<'tcx>(cx: &LateContext<'tcx>, arg_id: hir::HirId, expr: &'tc hir::ExprKind::Match(_, arms, _) => { let mut found_mapping = false; let mut found_filtering = false; - for arm in *arms { + for arm in arms { let (m, f) = check_expression(cx, arg_id, arm.body); found_mapping |= m; found_filtering |= f; @@ -94,39 +98,9 @@ fn check_expression<'tcx>(cx: &LateContext<'tcx>, arg_id: hir::HirId, expr: &'tc let else_check = check_expression(cx, arg_id, else_arm); (if_check.0 | else_check.0, if_check.1 | else_check.1) }, - hir::ExprKind::Path(path) if is_lang_ctor(cx, path, OptionNone) => (false, true), + hir::ExprKind::Path(ref path) if is_res_lang_ctor(cx, cx.qpath_res(path, expr.hir_id), OptionNone) => { + (false, true) + }, _ => (true, true), } } - -struct ReturnVisitor<'a, 'tcx> { - cx: &'a LateContext<'tcx>, - arg_id: hir::HirId, - // Found a non-None return that isn't Some(input) - found_mapping: bool, - // Found a return that isn't Some - found_filtering: bool, -} - -impl<'a, 'tcx> ReturnVisitor<'a, 'tcx> { - fn new(cx: &'a LateContext<'tcx>, arg_id: hir::HirId) -> ReturnVisitor<'a, 'tcx> { - ReturnVisitor { - cx, - arg_id, - found_mapping: false, - found_filtering: false, - } - } -} - -impl<'a, 'tcx> Visitor<'tcx> for ReturnVisitor<'a, 'tcx> { - fn visit_expr(&mut self, expr: &'tcx hir::Expr<'_>) { - if let hir::ExprKind::Ret(Some(expr)) = &expr.kind { - let (found_mapping, found_filtering) = check_expression(self.cx, self.arg_id, expr); - self.found_mapping |= found_mapping; - self.found_filtering |= found_filtering; - } else { - walk_expr(self, expr); - } - } -} |