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Auto merge of #7403 - Anthuang:redundant-method-names, r=Manishearth
New lint: [`self_named_constructor`] Adds the `self_named_constructor` lint for detecting when an implemented method has the same name as the type it is implemented for. changelog: [`self_named_constructor`] closes: #7142
2 parents 46363df + e9e10d2 commit f70a074

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-64
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‎CHANGELOG.md‎

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@@ -2772,6 +2772,7 @@ Released 2018-09-13
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[`same_item_push`]: https://rust-lang.github.io/rust-clippy/master/index.html#same_item_push
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[`search_is_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#search_is_some
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[`self_assignment`]: https://rust-lang.github.io/rust-clippy/master/index.html#self_assignment
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[`self_named_constructor`]: https://rust-lang.github.io/rust-clippy/master/index.html#self_named_constructor
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[`semicolon_if_nothing_returned`]: https://rust-lang.github.io/rust-clippy/master/index.html#semicolon_if_nothing_returned
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[`serde_api_misuse`]: https://rust-lang.github.io/rust-clippy/master/index.html#serde_api_misuse
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[`shadow_reuse`]: https://rust-lang.github.io/rust-clippy/master/index.html#shadow_reuse

‎clippy_lints/src/lib.rs‎

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@@ -330,6 +330,7 @@ mod regex;
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mod repeat_once;
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mod returns;
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mod self_assignment;
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mod self_named_constructor;
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mod semicolon_if_nothing_returned;
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mod serde_api;
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mod shadow;
@@ -900,6 +901,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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returns::LET_AND_RETURN,
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returns::NEEDLESS_RETURN,
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self_assignment::SELF_ASSIGNMENT,
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self_named_constructor::SELF_NAMED_CONSTRUCTOR,
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semicolon_if_nothing_returned::SEMICOLON_IF_NOTHING_RETURNED,
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serde_api::SERDE_API_MISUSE,
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shadow::SHADOW_REUSE,
@@ -1406,6 +1408,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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LintId::of(returns::LET_AND_RETURN),
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LintId::of(returns::NEEDLESS_RETURN),
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LintId::of(self_assignment::SELF_ASSIGNMENT),
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LintId::of(self_named_constructor::SELF_NAMED_CONSTRUCTOR),
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LintId::of(serde_api::SERDE_API_MISUSE),
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LintId::of(single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
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LintId::of(size_of_in_element_count::SIZE_OF_IN_ELEMENT_COUNT),
@@ -1559,6 +1562,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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LintId::of(redundant_static_lifetimes::REDUNDANT_STATIC_LIFETIMES),
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LintId::of(returns::LET_AND_RETURN),
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LintId::of(returns::NEEDLESS_RETURN),
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LintId::of(self_named_constructor::SELF_NAMED_CONSTRUCTOR),
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LintId::of(single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS),
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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),
@@ -2101,6 +2105,8 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
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let scripts = conf.allowed_scripts.clone();
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store.register_early_pass(move || box disallowed_script_idents::DisallowedScriptIdents::new(&scripts));
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store.register_late_pass(|| box strlen_on_c_strings::StrlenOnCStrings);
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store.register_late_pass(move || box self_named_constructor::SelfNamedConstructor);
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}
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#[rustfmt::skip]

‎clippy_lints/src/self_named_constructor.rs‎

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@@ -0,0 +1,91 @@
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use clippy_utils::diagnostics::span_lint;
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use clippy_utils::return_ty;
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use clippy_utils::ty::{contains_adt_constructor, contains_ty};
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use rustc_hir::{Impl, ImplItem, ImplItemKind, ItemKind, Node};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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declare_clippy_lint! {
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/// **What it does:** Warns when constructors have the same name as their types.
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///
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/// **Why is this bad?** Repeating the name of the type is redundant.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// ```rust,ignore
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/// struct Foo {}
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///
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/// impl Foo {
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/// pub fn foo() -> Foo {
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/// Foo {}
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/// }
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/// }
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/// ```
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/// Use instead:
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/// ```rust,ignore
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/// struct Foo {}
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///
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/// impl Foo {
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/// pub fn new() -> Foo {
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/// Foo {}
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/// }
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/// }
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/// ```
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pub SELF_NAMED_CONSTRUCTOR,
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style,
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"method should not have the same name as the type it is implemented for"
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}
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declare_lint_pass!(SelfNamedConstructor => [SELF_NAMED_CONSTRUCTOR]);
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impl<'tcx> LateLintPass<'tcx> for SelfNamedConstructor {
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fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx ImplItem<'_>) {
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match impl_item.kind {
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ImplItemKind::Fn(ref sig, _) => {
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if sig.decl.implicit_self.has_implicit_self() {
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return;
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}
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},
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_ => return,
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}
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let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
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let item = cx.tcx.hir().expect_item(parent);
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let self_ty = cx.tcx.type_of(item.def_id);
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let ret_ty = return_ty(cx, impl_item.hir_id());
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// Do not check trait impls
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if matches!(item.kind, ItemKind::Impl(Impl { of_trait: Some(_), .. })) {
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return;
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}
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// Ensure method is constructor-like
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if let Some(self_adt) = self_ty.ty_adt_def() {
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if !contains_adt_constructor(ret_ty, self_adt) {
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return;
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}
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} else if !contains_ty(ret_ty, self_ty) {
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return;
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}
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if_chain! {
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if let Some(self_def) = self_ty.ty_adt_def();
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if let Some(self_local_did) = self_def.did.as_local();
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let self_id = cx.tcx.hir().local_def_id_to_hir_id(self_local_did);
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if let Some(Node::Item(x)) = cx.tcx.hir().find(self_id);
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let type_name = x.ident.name.as_str().to_lowercase();
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if impl_item.ident.name.as_str() == type_name || impl_item.ident.name.as_str().replace("_", "") == type_name;
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then {
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span_lint(
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cx,
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SELF_NAMED_CONSTRUCTOR,
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impl_item.span,
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&format!("constructor `{}` has the same name as the type", impl_item.ident.name),
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);
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}
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}
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}
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}

‎tests/ui/crashes/ice-6179.rs‎

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@@ -7,7 +7,7 @@
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struct Foo {}
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impl Foo {
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fn foo() -> Self {
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fn new() -> Self {
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impl Foo {
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fn bar() {}
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}

‎tests/ui/issue_4266.rs‎

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@@ -25,7 +25,9 @@ async fn all_to_one<'a>(a: &'a str, _b: &'a str) -> &'a str {
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struct Foo;
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impl Foo {
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// ok
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pub async fn foo(&mut self) {}
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pub async fn new(&mut self) -> Self {
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Foo {}
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}
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}
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// rust-lang/rust#61115

‎tests/ui/missing-doc-impl.rs‎

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@@ -59,7 +59,9 @@ pub trait E: Sized {
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}
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impl Foo {
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pub fn foo() {}
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pub fn new() -> Self {
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Foo { a: 0, b: 0 }
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}
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fn bar() {}
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}
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‎tests/ui/missing-doc-impl.stderr‎

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@@ -78,23 +78,25 @@ LL | type AssociatedTypeDef = Self;
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error: missing documentation for an associated function
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--> $DIR/missing-doc-impl.rs:62:5
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|
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LL | pub fn foo() {}
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| ^^^^^^^^^^^^^^^
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LL | / pub fn new() -> Self {
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LL | | Foo { a: 0, b: 0 }
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LL | | }
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| |_____^
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error: missing documentation for an associated function
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--> $DIR/missing-doc-impl.rs:63:5
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--> $DIR/missing-doc-impl.rs:65:5
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|
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LL | fn bar() {}
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| ^^^^^^^^^^^
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error: missing documentation for an associated function
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--> $DIR/missing-doc-impl.rs:67:5
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--> $DIR/missing-doc-impl.rs:69:5
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|
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LL | pub fn foo() {}
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| ^^^^^^^^^^^^^^^
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error: missing documentation for an associated function
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--> $DIR/missing-doc-impl.rs:71:5
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--> $DIR/missing-doc-impl.rs:73:5
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|
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LL | / fn foo2() -> u32 {
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LL | | 1

‎tests/ui/missing_const_for_fn/cant_be_const.rs‎

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@@ -84,7 +84,7 @@ mod with_drop {
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impl A {
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// This can not be const because the type implements `Drop`.
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pub fn a(self) -> B {
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pub fn b(self) -> B {
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B
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}
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}

‎tests/ui/needless_bool/fixable.fixed‎

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@@ -6,7 +6,8 @@
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dead_code,
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clippy::no_effect,
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clippy::if_same_then_else,
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clippy::needless_return
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clippy::needless_return,
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clippy::self_named_constructor
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)]
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use std::cell::Cell;

‎tests/ui/needless_bool/fixable.rs‎

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@@ -6,7 +6,8 @@
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dead_code,
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clippy::no_effect,
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clippy::if_same_then_else,
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clippy::needless_return
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clippy::needless_return,
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clippy::self_named_constructor
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)]
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use std::cell::Cell;

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