X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Fmethods%2Fmod.rs;h=5c8add5f3022612433100379cc5006297e91e434;hb=a8151409a0352c4141fc823cdbbd70edfdf88366;hp=996d4cb412344ae7e9ea01154ec3791cf6ffc0c7;hpb=3d4b73c26da1630318e76f43a7dedfc4dbc716cd;p=rust.git diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 996d4cb4123..5c8add5f302 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -54,6 +54,7 @@ mod map_identity; mod map_unwrap_or; mod mut_mutex_lock; +mod needless_collect; mod needless_option_as_deref; mod needless_option_take; mod no_effect_replace; @@ -157,9 +158,9 @@ /// ``` /// Use instead: /// ```rust - /// let hello = "hesuo worpd".replace(&['s', 'u', 'p'], "l"); + /// let hello = "hesuo worpd".replace(['s', 'u', 'p'], "l"); /// ``` - #[clippy::version = "1.64.0"] + #[clippy::version = "1.65.0"] pub COLLAPSIBLE_STR_REPLACE, perf, "collapse consecutive calls to str::replace (2 or more) into a single call" @@ -1729,7 +1730,7 @@ declare_clippy_lint! { /// ### What it does - /// Checks for usage of `_.as_ref().map(Deref::deref)` or it's aliases (such as String::as_str). + /// Checks for usage of `_.as_ref().map(Deref::deref)` or its aliases (such as String::as_str). /// /// ### Why is this bad? /// Readability, this can be written more concisely as @@ -2095,8 +2096,7 @@ /// let s = "Hello world!"; /// let cow = Cow::Borrowed(s); /// - /// let data = cow.into_owned(); - /// assert!(matches!(data, String)) + /// let _data: String = cow.into_owned(); /// ``` #[clippy::version = "1.65.0"] pub SUSPICIOUS_TO_OWNED, @@ -2427,7 +2427,7 @@ /// ### Known problems /// /// The type of the resulting iterator might become incompatible with its usage - #[clippy::version = "1.64.0"] + #[clippy::version = "1.65.0"] pub ITER_ON_SINGLE_ITEMS, nursery, "Iterator for array of length 1" @@ -2459,7 +2459,7 @@ /// ### Known problems /// /// The type of the resulting iterator might become incompatible with its usage - #[clippy::version = "1.64.0"] + #[clippy::version = "1.65.0"] pub ITER_ON_EMPTY_COLLECTIONS, nursery, "Iterator for empty array" @@ -3141,6 +3141,28 @@ "jumping to the start of stream using `seek` method" } +declare_clippy_lint! { + /// ### What it does + /// Checks for functions collecting an iterator when collect + /// is not needed. + /// + /// ### Why is this bad? + /// `collect` causes the allocation of a new data structure, + /// when this allocation may not be needed. + /// + /// ### Example + /// ```rust + /// # let iterator = vec![1].into_iter(); + /// let len = iterator.clone().collect::>().len(); + /// // should be + /// let len = iterator.count(); + /// ``` + #[clippy::version = "1.30.0"] + pub NEEDLESS_COLLECT, + nursery, + "collecting an iterator when collect is not needed" +} + pub struct Methods { avoid_breaking_exported_api: bool, msrv: Option, @@ -3267,16 +3289,17 @@ pub fn new( ITER_KV_MAP, SEEK_FROM_CURRENT, SEEK_TO_START_INSTEAD_OF_REWIND, + NEEDLESS_COLLECT, ]); /// Extracts a method call name, args, and `Span` of the method name. fn method_call<'tcx>( recv: &'tcx hir::Expr<'tcx>, -) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span)> { - if let ExprKind::MethodCall(path, receiver, args, _) = recv.kind { +) -> Option<(&'tcx str, &'tcx hir::Expr<'tcx>, &'tcx [hir::Expr<'tcx>], Span, Span)> { + if let ExprKind::MethodCall(path, receiver, args, call_span) = recv.kind { if !args.iter().any(|e| e.span.from_expansion()) && !receiver.span.from_expansion() { let name = path.ident.name.as_str(); - return Some((name, receiver, args, path.ident.span)); + return Some((name, receiver, args, path.ident.span, call_span)); } } None @@ -3462,7 +3485,7 @@ fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'_> impl Methods { #[allow(clippy::too_many_lines)] fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { - if let Some((name, recv, args, span)) = method_call(expr) { + if let Some((name, recv, args, span, call_span)) = method_call(expr) { match (name, args) { ("add" | "offset" | "sub" | "wrapping_offset" | "wrapping_add" | "wrapping_sub", [_arg]) => { zst_offset::check(cx, expr, recv); @@ -3481,28 +3504,31 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { ("as_ref", []) => useless_asref::check(cx, expr, "as_ref", recv), ("assume_init", []) => uninit_assumed_init::check(cx, expr, recv), ("cloned", []) => cloned_instead_of_copied::check(cx, expr, recv, span, self.msrv), - ("collect", []) => match method_call(recv) { - Some((name @ ("cloned" | "copied"), recv2, [], _)) => { - iter_cloned_collect::check(cx, name, expr, recv2); - }, - Some(("map", m_recv, [m_arg], _)) => { - map_collect_result_unit::check(cx, expr, m_recv, m_arg, recv); - }, - Some(("take", take_self_arg, [take_arg], _)) => { - if meets_msrv(self.msrv, msrvs::STR_REPEAT) { - manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg); - } - }, - _ => {}, + ("collect", []) if is_trait_method(cx, expr, sym::Iterator) => { + needless_collect::check(cx, span, expr, recv, call_span); + match method_call(recv) { + Some((name @ ("cloned" | "copied"), recv2, [], _, _)) => { + iter_cloned_collect::check(cx, name, expr, recv2); + }, + Some(("map", m_recv, [m_arg], _, _)) => { + map_collect_result_unit::check(cx, expr, m_recv, m_arg); + }, + Some(("take", take_self_arg, [take_arg], _, _)) => { + if meets_msrv(self.msrv, msrvs::STR_REPEAT) { + manual_str_repeat::check(cx, expr, recv, take_self_arg, take_arg); + } + }, + _ => {}, + } }, ("count", []) if is_trait_method(cx, expr, sym::Iterator) => match method_call(recv) { - Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false), - Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _)) => { + Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, true, false), + Some((name2 @ ("into_iter" | "iter" | "iter_mut"), recv2, [], _, _)) => { iter_count::check(cx, expr, recv2, name2); }, - Some(("map", _, [arg], _)) => suspicious_map::check(cx, expr, recv, arg), - Some(("filter", recv2, [arg], _)) => bytecount::check(cx, expr, recv2, arg), - Some(("bytes", recv2, [], _)) => bytes_count_to_len::check(cx, expr, recv, recv2), + Some(("map", _, [arg], _, _)) => suspicious_map::check(cx, expr, recv, arg), + Some(("filter", recv2, [arg], _, _)) => bytecount::check(cx, expr, recv2, arg), + Some(("bytes", recv2, [], _, _)) => bytes_count_to_len::check(cx, expr, recv, recv2), _ => {}, }, ("drain", [arg]) => { @@ -3514,8 +3540,8 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { } }, ("expect", [_]) => match method_call(recv) { - Some(("ok", recv, [], _)) => ok_expect::check(cx, expr, recv), - Some(("err", recv, [], err_span)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span), + Some(("ok", recv, [], _, _)) => ok_expect::check(cx, expr, recv), + Some(("err", recv, [], err_span, _)) => err_expect::check(cx, expr, recv, self.msrv, span, err_span), _ => expect_used::check(cx, expr, recv, false, self.allow_expect_in_tests), }, ("expect_err", [_]) => expect_used::check(cx, expr, recv, true, self.allow_expect_in_tests), @@ -3535,13 +3561,13 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { flat_map_option::check(cx, expr, arg, span); }, ("flatten", []) => match method_call(recv) { - Some(("map", recv, [map_arg], map_span)) => map_flatten::check(cx, expr, recv, map_arg, map_span), - Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true), + Some(("map", recv, [map_arg], map_span, _)) => map_flatten::check(cx, expr, recv, map_arg, map_span), + Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, true), _ => {}, }, ("fold", [init, acc]) => unnecessary_fold::check(cx, expr, init, acc, span), ("for_each", [_]) => { - if let Some(("inspect", _, [_], span2)) = method_call(recv) { + if let Some(("inspect", _, [_], span2, _)) = method_call(recv) { inspect_for_each::check(cx, expr, span2); } }, @@ -3561,12 +3587,12 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { iter_on_single_or_empty_collections::check(cx, expr, name, recv); }, ("join", [join_arg]) => { - if let Some(("collect", _, _, span)) = method_call(recv) { + if let Some(("collect", _, _, span, _)) = method_call(recv) { unnecessary_join::check(cx, expr, recv, join_arg, span); } }, ("last", []) | ("skip", [_]) => { - if let Some((name2, recv2, args2, _span2)) = method_call(recv) { + if let Some((name2, recv2, args2, _span2, _)) = method_call(recv) { if let ("cloned", []) = (name2, args2) { iter_overeager_cloned::check(cx, expr, recv, recv2, false, false); } @@ -3578,13 +3604,13 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { (name @ ("map" | "map_err"), [m_arg]) => { if name == "map" { map_clone::check(cx, expr, recv, m_arg, self.msrv); - if let Some((map_name @ ("iter" | "into_iter"), recv2, _, _)) = method_call(recv) { + if let Some((map_name @ ("iter" | "into_iter"), recv2, _, _, _)) = method_call(recv) { iter_kv_map::check(cx, map_name, expr, recv2, m_arg); } } else { map_err_ignore::check(cx, expr, m_arg); } - if let Some((name, recv2, args, span2)) = method_call(recv) { + if let Some((name, recv2, args, span2,_)) = method_call(recv) { match (name, args) { ("as_mut", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, true, self.msrv), ("as_ref", []) => option_as_ref_deref::check(cx, expr, recv2, m_arg, false, self.msrv), @@ -3604,7 +3630,7 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { manual_ok_or::check(cx, expr, recv, def, map); }, ("next", []) => { - if let Some((name2, recv2, args2, _)) = method_call(recv) { + if let Some((name2, recv2, args2, _, _)) = method_call(recv) { match (name2, args2) { ("cloned", []) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false), ("filter", [arg]) => filter_next::check(cx, expr, recv2, arg), @@ -3617,10 +3643,10 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { } }, ("nth", [n_arg]) => match method_call(recv) { - Some(("bytes", recv2, [], _)) => bytes_nth::check(cx, expr, recv2, n_arg), - Some(("cloned", recv2, [], _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false), - Some(("iter", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false), - Some(("iter_mut", recv2, [], _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true), + Some(("bytes", recv2, [], _, _)) => bytes_nth::check(cx, expr, recv2, n_arg), + Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(cx, expr, recv, recv2, false, false), + Some(("iter", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false), + Some(("iter_mut", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true), _ => iter_nth_zero::check(cx, expr, recv, n_arg), }, ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"), @@ -3685,7 +3711,7 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { }, ("step_by", [arg]) => iterator_step_by_zero::check(cx, expr, arg), ("take", [_arg]) => { - if let Some((name2, recv2, args2, _span2)) = method_call(recv) { + if let Some((name2, recv2, args2, _span2, _)) = method_call(recv) { if let ("cloned", []) = (name2, args2) { iter_overeager_cloned::check(cx, expr, recv, recv2, false, false); } @@ -3708,13 +3734,13 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { }, ("unwrap", []) => { match method_call(recv) { - Some(("get", recv, [get_arg], _)) => { + Some(("get", recv, [get_arg], _, _)) => { get_unwrap::check(cx, expr, recv, get_arg, false); }, - Some(("get_mut", recv, [get_arg], _)) => { + Some(("get_mut", recv, [get_arg], _, _)) => { get_unwrap::check(cx, expr, recv, get_arg, true); }, - Some(("or", recv, [or_arg], or_span)) => { + Some(("or", recv, [or_arg], or_span, _)) => { or_then_unwrap::check(cx, expr, recv, or_arg, or_span); }, _ => {}, @@ -3723,19 +3749,19 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { }, ("unwrap_err", []) => unwrap_used::check(cx, expr, recv, true, self.allow_unwrap_in_tests), ("unwrap_or", [u_arg]) => match method_call(recv) { - Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _)) => { + Some((arith @ ("checked_add" | "checked_sub" | "checked_mul"), lhs, [rhs], _, _)) => { manual_saturating_arithmetic::check(cx, expr, lhs, rhs, u_arg, &arith["checked_".len()..]); }, - Some(("map", m_recv, [m_arg], span)) => { + Some(("map", m_recv, [m_arg], span, _)) => { option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span); }, - Some(("then_some", t_recv, [t_arg], _)) => { + Some(("then_some", t_recv, [t_arg], _, _)) => { obfuscated_if_else::check(cx, expr, t_recv, t_arg, u_arg); }, _ => {}, }, ("unwrap_or_else", [u_arg]) => match method_call(recv) { - Some(("map", recv, [map_arg], _)) + Some(("map", recv, [map_arg], _, _)) if map_unwrap_or::check(cx, expr, recv, map_arg, u_arg, self.msrv) => {}, _ => { unwrap_or_else_default::check(cx, expr, recv, u_arg); @@ -3756,7 +3782,7 @@ fn check_methods<'tcx>(&self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { } fn check_is_some_is_none(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, is_some: bool) { - if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span)) = method_call(recv) { + if let Some((name @ ("find" | "position" | "rposition"), f_recv, [arg], span, _)) = method_call(recv) { search_is_some::check(cx, expr, name, is_some, f_recv, arg, recv, span); } }