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add trim_split_whitespace
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‎CHANGELOG.md‎

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@@ -3736,6 +3736,7 @@ Released 2018-09-13
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[`transmute_undefined_repr`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmute_undefined_repr
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[`transmutes_expressible_as_ptr_casts`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmutes_expressible_as_ptr_casts
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[`transmuting_null`]: https://rust-lang.github.io/rust-clippy/master/index.html#transmuting_null
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[`trim_split_whitespace`]: https://rust-lang.github.io/rust-clippy/master/index.html#trim_split_whitespace
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[`trivial_regex`]: https://rust-lang.github.io/rust-clippy/master/index.html#trivial_regex
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[`trivially_copy_pass_by_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#trivially_copy_pass_by_ref
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[`try_err`]: https://rust-lang.github.io/rust-clippy/master/index.html#try_err

‎clippy_lints/src/lib.register_all.rs‎

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@@ -281,6 +281,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
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LintId::of(size_of_in_element_count::SIZE_OF_IN_ELEMENT_COUNT),
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LintId::of(slow_vector_initialization::SLOW_VECTOR_INITIALIZATION),
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LintId::of(strings::STRING_FROM_UTF8_AS_BYTES),
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LintId::of(strings::TRIM_SPLIT_WHITESPACE),
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LintId::of(strlen_on_c_strings::STRLEN_ON_C_STRINGS),
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LintId::of(suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL),
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LintId::of(suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL),

‎clippy_lints/src/lib.register_lints.rs‎

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@@ -482,6 +482,7 @@ store.register_lints(&[
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strings::STRING_SLICE,
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strings::STRING_TO_STRING,
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strings::STR_TO_STRING,
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strings::TRIM_SPLIT_WHITESPACE,
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strlen_on_c_strings::STRLEN_ON_C_STRINGS,
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suspicious_operation_groupings::SUSPICIOUS_OPERATION_GROUPINGS,
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suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL,

‎clippy_lints/src/lib.register_style.rs‎

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@@ -105,6 +105,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
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LintId::of(returns::NEEDLESS_RETURN),
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LintId::of(self_named_constructors::SELF_NAMED_CONSTRUCTORS),
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LintId::of(single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
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LintId::of(strings::TRIM_SPLIT_WHITESPACE),
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LintId::of(tabs_in_doc_comments::TABS_IN_DOC_COMMENTS),
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LintId::of(to_digit_is_some::TO_DIGIT_IS_SOME),
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LintId::of(unit_types::LET_UNIT_VALUE),

‎clippy_lints/src/lib.rs‎

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@@ -887,6 +887,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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store.register_late_pass(|| Box::new(bytes_count_to_len::BytesCountToLen));
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let max_include_file_size = conf.max_include_file_size;
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store.register_late_pass(move || Box::new(large_include_file::LargeIncludeFile::new(max_include_file_size)));
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store.register_late_pass(|| Box::new(strings::TrimSplitWhitespace));
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// add lints here, do not remove this comment, it's used in `new_lint`
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}
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‎clippy_lints/src/strings.rs‎

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@@ -5,6 +5,7 @@ use clippy_utils::{get_parent_expr, is_lint_allowed, match_function_call, method
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use clippy_utils::{peel_blocks, SpanlessEq};
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::def_id::DefId;
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use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, LangItem, QPath};
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use rustc_lint::{LateContext, LateLintPass, LintContext};
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use rustc_middle::lint::in_external_macro;
@@ -451,3 +452,58 @@ impl<'tcx> LateLintPass<'tcx> for StringToString {
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}
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}
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}
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declare_clippy_lint! {
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/// ### What it does
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/// Warns about calling `str::trim` (or variants) before `str::split_whitespace`.
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///
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/// ### Why is this bad?
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/// `split_whitespace` already ignores leading and trailing whitespace.
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///
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/// ### Example
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/// ```rust
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/// " A B C ".trim().split_whitespace();
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/// ```
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/// Use instead:
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/// ```rust
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/// " A B C ".split_whitespace();
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/// ```
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#[clippy::version = "1.62.0"]
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pub TRIM_SPLIT_WHITESPACE,
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style,
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"using `str::trim()` or alike before `str::split_whitespace`"
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}
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declare_lint_pass!(TrimSplitWhitespace => [TRIM_SPLIT_WHITESPACE]);
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impl<'tcx> LateLintPass<'tcx> for TrimSplitWhitespace {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'_>) {
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let tyckres = cx.typeck_results();
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if_chain! {
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if let ExprKind::MethodCall(path, [split_recv], split_ws_span) = expr.kind;
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if path.ident.name == sym!(split_whitespace);
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if let Some(split_ws_def_id) = tyckres.type_dependent_def_id(expr.hir_id);
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if cx.tcx.is_diagnostic_item(sym::str_split_whitespace, split_ws_def_id);
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if let ExprKind::MethodCall(path, [_trim_recv], trim_span) = split_recv.kind;
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if let trim_fn_name @ ("trim" | "trim_start" | "trim_end") = path.ident.name.as_str();
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if let Some(trim_def_id) = tyckres.type_dependent_def_id(split_recv.hir_id);
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if is_one_of_trim_diagnostic_items(cx, trim_def_id);
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then {
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span_lint_and_sugg(
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cx,
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TRIM_SPLIT_WHITESPACE,
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trim_span.with_hi(split_ws_span.lo()),
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&format!("found call to `str::{}` before `str::split_whitespace`", trim_fn_name),
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&format!("remove `{}()`", trim_fn_name),
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String::new(),
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Applicability::MachineApplicable,
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);
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}
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}
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}
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}
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fn is_one_of_trim_diagnostic_items(cx: &LateContext<'_>, trim_def_id: DefId) -> bool {
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cx.tcx.is_diagnostic_item(sym::str_trim, trim_def_id)
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|| cx.tcx.is_diagnostic_item(sym::str_trim_start, trim_def_id)
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|| cx.tcx.is_diagnostic_item(sym::str_trim_end, trim_def_id)
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}

‎tests/ui/trim_split_whitespace.fixed‎

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@@ -0,0 +1,91 @@
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// run-rustfix
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#![warn(clippy::trim_split_whitespace)]
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#![allow(clippy::let_unit_value)]
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struct Custom;
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impl Custom {
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fn trim(self) -> Self {
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self
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}
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fn split_whitespace(self) {}
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}
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struct DerefStr(&'static str);
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impl std::ops::Deref for DerefStr {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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struct DerefStrAndCustom(&'static str);
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impl std::ops::Deref for DerefStrAndCustom {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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impl DerefStrAndCustom {
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fn trim(self) -> Self {
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self
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}
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fn split_whitespace(self) {}
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}
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struct DerefStrAndCustomSplit(&'static str);
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impl std::ops::Deref for DerefStrAndCustomSplit {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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impl DerefStrAndCustomSplit {
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#[allow(dead_code)]
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fn split_whitespace(self) {}
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}
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struct DerefStrAndCustomTrim(&'static str);
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impl std::ops::Deref for DerefStrAndCustomTrim {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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impl DerefStrAndCustomTrim {
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fn trim(self) -> Self {
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self
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}
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}
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fn main() {
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// &str
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let _ = " A B C ".split_whitespace(); // should trigger lint
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let _ = " A B C ".split_whitespace(); // should trigger lint
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let _ = " A B C ".split_whitespace(); // should trigger lint
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// String
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let _ = (" A B C ").to_string().split_whitespace(); // should trigger lint
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let _ = (" A B C ").to_string().split_whitespace(); // should trigger lint
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let _ = (" A B C ").to_string().split_whitespace(); // should trigger lint
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// Custom
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let _ = Custom.trim().split_whitespace(); // should not trigger lint
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// Deref<Target=str>
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let s = DerefStr(" A B C ");
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let _ = s.split_whitespace(); // should trigger lint
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// Deref<Target=str> + custom impl
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let s = DerefStrAndCustom(" A B C ");
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let _ = s.trim().split_whitespace(); // should not trigger lint
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// Deref<Target=str> + only custom split_ws() impl
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let s = DerefStrAndCustomSplit(" A B C ");
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let _ = s.split_whitespace(); // should trigger lint
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// Expl: trim() is called on str (deref) and returns &str.
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// Thus split_ws() is called on str as well and the custom impl on S is unused
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// Deref<Target=str> + only custom trim() impl
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let s = DerefStrAndCustomTrim(" A B C ");
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let _ = s.trim().split_whitespace(); // should not trigger lint
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}

‎tests/ui/trim_split_whitespace.rs‎

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@@ -0,0 +1,91 @@
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// run-rustfix
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#![warn(clippy::trim_split_whitespace)]
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#![allow(clippy::let_unit_value)]
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struct Custom;
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impl Custom {
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fn trim(self) -> Self {
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self
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}
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fn split_whitespace(self) {}
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}
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struct DerefStr(&'static str);
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impl std::ops::Deref for DerefStr {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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struct DerefStrAndCustom(&'static str);
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impl std::ops::Deref for DerefStrAndCustom {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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impl DerefStrAndCustom {
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fn trim(self) -> Self {
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self
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}
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fn split_whitespace(self) {}
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}
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struct DerefStrAndCustomSplit(&'static str);
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impl std::ops::Deref for DerefStrAndCustomSplit {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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impl DerefStrAndCustomSplit {
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#[allow(dead_code)]
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fn split_whitespace(self) {}
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}
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struct DerefStrAndCustomTrim(&'static str);
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impl std::ops::Deref for DerefStrAndCustomTrim {
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type Target = str;
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fn deref(&self) -> &Self::Target {
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self.0
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}
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}
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impl DerefStrAndCustomTrim {
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fn trim(self) -> Self {
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self
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}
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}
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fn main() {
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// &str
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let _ = " A B C ".trim().split_whitespace(); // should trigger lint
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let _ = " A B C ".trim_start().split_whitespace(); // should trigger lint
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let _ = " A B C ".trim_end().split_whitespace(); // should trigger lint
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// String
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let _ = (" A B C ").to_string().trim().split_whitespace(); // should trigger lint
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let _ = (" A B C ").to_string().trim_start().split_whitespace(); // should trigger lint
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let _ = (" A B C ").to_string().trim_end().split_whitespace(); // should trigger lint
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// Custom
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let _ = Custom.trim().split_whitespace(); // should not trigger lint
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// Deref<Target=str>
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let s = DerefStr(" A B C ");
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let _ = s.trim().split_whitespace(); // should trigger lint
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// Deref<Target=str> + custom impl
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let s = DerefStrAndCustom(" A B C ");
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let _ = s.trim().split_whitespace(); // should not trigger lint
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// Deref<Target=str> + only custom split_ws() impl
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let s = DerefStrAndCustomSplit(" A B C ");
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let _ = s.trim().split_whitespace(); // should trigger lint
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// Expl: trim() is called on str (deref) and returns &str.
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// Thus split_ws() is called on str as well and the custom impl on S is unused
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// Deref<Target=str> + only custom trim() impl
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let s = DerefStrAndCustomTrim(" A B C ");
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let _ = s.trim().split_whitespace(); // should not trigger lint
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}

‎tests/ui/trim_split_whitespace.stderr‎

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error: found call to `str::trim` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:62:23
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|
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LL | let _ = " A B C ".trim().split_whitespace(); // should trigger lint
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| ^^^^^^^ help: remove `trim()`
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|
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= note: `-D clippy::trim-split-whitespace` implied by `-D warnings`
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error: found call to `str::trim_start` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:63:23
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|
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LL | let _ = " A B C ".trim_start().split_whitespace(); // should trigger lint
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| ^^^^^^^^^^^^^ help: remove `trim_start()`
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error: found call to `str::trim_end` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:64:23
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|
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LL | let _ = " A B C ".trim_end().split_whitespace(); // should trigger lint
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| ^^^^^^^^^^^ help: remove `trim_end()`
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error: found call to `str::trim` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:67:37
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|
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LL | let _ = (" A B C ").to_string().trim().split_whitespace(); // should trigger lint
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| ^^^^^^^ help: remove `trim()`
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error: found call to `str::trim_start` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:68:37
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|
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LL | let _ = (" A B C ").to_string().trim_start().split_whitespace(); // should trigger lint
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| ^^^^^^^^^^^^^ help: remove `trim_start()`
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error: found call to `str::trim_end` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:69:37
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|
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LL | let _ = (" A B C ").to_string().trim_end().split_whitespace(); // should trigger lint
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| ^^^^^^^^^^^ help: remove `trim_end()`
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error: found call to `str::trim` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:76:15
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|
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LL | let _ = s.trim().split_whitespace(); // should trigger lint
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| ^^^^^^^ help: remove `trim()`
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error: found call to `str::trim` before `str::split_whitespace`
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--> $DIR/trim_split_whitespace.rs:84:15
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|
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LL | let _ = s.trim().split_whitespace(); // should trigger lint
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| ^^^^^^^ help: remove `trim()`
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error: aborting due to 8 previous errors
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