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Add [extern_without_abi] lint
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‎CHANGELOG.md

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@@ -5456,6 +5456,7 @@ Released 2018-09-13
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[`explicit_write`]: https://rust-lang.github.io/rust-clippy/master/index.html#explicit_write
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[`extend_from_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#extend_from_slice
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[`extend_with_drain`]: https://rust-lang.github.io/rust-clippy/master/index.html#extend_with_drain
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[`extern_without_abi`]: https://rust-lang.github.io/rust-clippy/master/index.html#extern_without_abi
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[`extra_unused_lifetimes`]: https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_lifetimes
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[`extra_unused_type_parameters`]: https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters
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[`fallible_impl_from`]: https://rust-lang.github.io/rust-clippy/master/index.html#fallible_impl_from

‎clippy_lints/src/declared_lints.rs

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@@ -173,6 +173,7 @@ pub static LINTS: &[&crate::LintInfo] = &[
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crate::exhaustive_items::EXHAUSTIVE_STRUCTS_INFO,
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crate::exit::EXIT_INFO,
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crate::explicit_write::EXPLICIT_WRITE_INFO,
176+
crate::extern_without_abi::EXTERN_WITHOUT_ABI_INFO,
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crate::extra_unused_type_parameters::EXTRA_UNUSED_TYPE_PARAMETERS_INFO,
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crate::fallible_impl_from::FALLIBLE_IMPL_FROM_INFO,
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crate::field_scoped_visibility_modifiers::FIELD_SCOPED_VISIBILITY_MODIFIERS_INFO,

‎clippy_lints/src/extern_without_abi.rs

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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::is_from_proc_macro;
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use clippy_utils::source::snippet;
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use rustc_errors::Applicability;
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use rustc_hir::def_id::LocalDefId;
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use rustc_hir::intravisit::FnKind;
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use rustc_hir::{Body, FnDecl, FnHeader, Item, ItemKind};
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use rustc_lint::{LateContext, LateLintPass, LintContext};
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use rustc_middle::lint::in_external_macro;
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use rustc_session::declare_lint_pass;
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use rustc_span::Span;
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use rustc_target::spec::abi::Abi;
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const LINT_MSG: &str = "`extern` missing explicit ABI";
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const LINT_HELP_MSG: &str = "consider using";
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const EXTERN: &str = "extern";
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const FN: &str = "fn";
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const OPEN_BRACE: &str = "{";
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const ABI: &str = "\"C\"";
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for usage of `extern` without an explicit ABI.
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///
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/// ### Why is this bad?
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/// Explicitly declaring the ABI is the recommended convention. See:
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/// [Rust Style Guide - `extern` items](https://doc.rust-lang.org/nightly/style-guide/items.html#extern-items)
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///
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/// It's also enforced by `rustfmt` when the `force_explicit_abi` option is enabled. See:
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/// [Configuring Rustfmt](https://rust-lang.github.io/rustfmt/?version=master&search=#force_explicit_abi)
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///
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/// ### Example
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/// ```no_run
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/// extern fn foo() {}
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///
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/// extern {
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/// fn bar();
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/// }
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/// ```
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/// Use instead:
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/// ```no_run
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/// extern "C" fn foo() {}
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///
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/// extern "C" {
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/// fn bar();
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/// }
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/// ```
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#[clippy::version = "1.83.0"]
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pub EXTERN_WITHOUT_ABI,
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style,
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"`extern` missing explicit ABI"
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}
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declare_lint_pass!(ExternWithoutAbi => [EXTERN_WITHOUT_ABI]);
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impl<'tcx> LateLintPass<'tcx> for ExternWithoutAbi {
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fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
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if let ItemKind::ForeignMod { abi: Abi::C { .. }, .. } = item.kind
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&& !in_external_macro(cx.sess(), item.span)
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&& !is_from_proc_macro(cx, item)
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&& let snippet = snippet(cx.sess(), item.span, "").as_ref()
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&& is_extern_followed_by(OPEN_BRACE, snippet)
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{
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emit_lint(cx, item.span, snippet);
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}
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}
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fn check_fn(
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&mut self,
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cx: &LateContext<'tcx>,
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kind: FnKind<'tcx>,
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_: &'tcx FnDecl<'tcx>,
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body: &'tcx Body<'tcx>,
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span: Span,
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_: LocalDefId,
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) {
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if let FnKind::ItemFn(_, _, header) = kind
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&& let FnHeader { abi: Abi::C { .. }, .. } = header
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&& !in_external_macro(cx.sess(), span)
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&& let hir_id = cx.tcx.hir().body_owner(body.id())
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&& !is_from_proc_macro(cx, &(&kind, body, hir_id, span))
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&& let snippet = snippet(cx.sess(), span, "").as_ref()
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&& is_extern_followed_by(FN, snippet)
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{
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emit_lint(cx, span, snippet);
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}
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}
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}
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fn is_extern_followed_by(item: &str, snippet: &str) -> bool {
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let mut tokens = snippet.split_whitespace();
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if let (_, Some(i)) = (tokens.next(), tokens.next())
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&& i.starts_with(item)
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{
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return true;
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}
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false
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}
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fn emit_lint(cx: &LateContext<'_>, span: Span, snippet: &str) {
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let sugg = snippet.replacen(EXTERN, format!("{EXTERN} {ABI}").as_str(), 1);
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span_lint_and_sugg(
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cx,
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EXTERN_WITHOUT_ABI,
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span,
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LINT_MSG,
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LINT_HELP_MSG,
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sugg,
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Applicability::MachineApplicable,
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);
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}

‎clippy_lints/src/lib.rs

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@@ -135,6 +135,7 @@ mod excessive_nesting;
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mod exhaustive_items;
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mod exit;
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mod explicit_write;
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mod extern_without_abi;
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mod extra_unused_type_parameters;
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mod fallible_impl_from;
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mod field_scoped_visibility_modifiers;
@@ -944,5 +945,6 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
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store.register_late_pass(|_| Box::new(manual_is_power_of_two::ManualIsPowerOfTwo));
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store.register_late_pass(|_| Box::new(non_zero_suggestions::NonZeroSuggestions));
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store.register_late_pass(move |_| Box::new(unused_trait_names::UnusedTraitNames::new(conf)));
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store.register_late_pass(|_| Box::new(extern_without_abi::ExternWithoutAbi));
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// add lints here, do not remove this comment, it's used in `new_lint`
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}

‎tests/ui/boxed_local.rs

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#![allow(
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clippy::borrowed_box,
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clippy::extern_without_abi,
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clippy::needless_pass_by_value,
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clippy::unused_unit,
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clippy::redundant_clone,

‎tests/ui/boxed_local.stderr

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@@ -1,5 +1,5 @@
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error: local variable doesn't need to be boxed here
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--> tests/ui/boxed_local.rs:39:13
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--> tests/ui/boxed_local.rs:40:13
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|
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LL | fn warn_arg(x: Box<A>) {
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| ^
@@ -8,19 +8,19 @@ LL | fn warn_arg(x: Box<A>) {
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= help: to override `-D warnings` add `#[allow(clippy::boxed_local)]`
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error: local variable doesn't need to be boxed here
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--> tests/ui/boxed_local.rs:122:12
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--> tests/ui/boxed_local.rs:123:12
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|
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LL | pub fn new(_needs_name: Box<PeekableSeekable<&()>>) -> () {}
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| ^^^^^^^^^^^
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error: local variable doesn't need to be boxed here
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--> tests/ui/boxed_local.rs:187:44
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--> tests/ui/boxed_local.rs:188:44
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|
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LL | fn default_impl_x(self: Box<Self>, x: Box<u32>) -> u32 {
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| ^
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error: local variable doesn't need to be boxed here
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--> tests/ui/boxed_local.rs:195:16
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--> tests/ui/boxed_local.rs:196:16
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|
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LL | fn foo(x: Box<u32>) {}
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| ^

‎tests/ui/doc/doc-fixable.fixed

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@@ -1,7 +1,7 @@
11

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//! This file tests for the `DOC_MARKDOWN` lint.
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#![allow(dead_code, incomplete_features)]
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#![allow(dead_code, incomplete_features, clippy::extern_without_abi)]
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#![warn(clippy::doc_markdown)]
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#![feature(custom_inner_attributes, generic_const_exprs, const_option)]
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#![rustfmt::skip]

‎tests/ui/doc/doc-fixable.rs

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//! This file tests for the `DOC_MARKDOWN` lint.
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#![allow(dead_code, incomplete_features)]
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#![allow(dead_code, incomplete_features, clippy::extern_without_abi)]
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#![warn(clippy::doc_markdown)]
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#![feature(custom_inner_attributes, generic_const_exprs, const_option)]
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#![rustfmt::skip]

‎tests/ui/extern_without_abi.fixed

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//@aux-build:proc_macros.rs
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#![warn(clippy::extern_without_abi)]
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extern crate proc_macros;
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use proc_macros::{external, with_span};
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#[rustfmt::skip]
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extern "C" fn foo() {}
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//~^ ERROR: `extern` missing explicit ABI
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#[rustfmt::skip]
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extern "C"
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fn foo_two() {}
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//~^^ ERROR: `extern` missing explicit ABI
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extern "C" fn bar() {}
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#[rustfmt::skip]
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extern
21+
"C"
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fn bar_two() {}
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extern "system" fn baz() {}
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#[rustfmt::skip]
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extern "C" {
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//~^ ERROR: `extern` missing explicit ABI
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fn qux();
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}
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#[rustfmt::skip]
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extern "C"
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{
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//~^^ ERROR: `extern` missing explicit ABI
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fn qux_two();
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}
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#[rustfmt::skip]
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extern "C" {fn qux_three();}
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//~^ ERROR: `extern` missing explicit ABI
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43+
extern "C" {
44+
fn grault();
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}
46+
47+
extern "system" {
48+
fn grault_two();
49+
}
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51+
external! {
52+
extern fn waldo() {}
53+
}
54+
55+
with_span! {
56+
span
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extern fn waldo_two() {}
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}
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60+
fn main() {}

‎tests/ui/extern_without_abi.rs

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//@aux-build:proc_macros.rs
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#![warn(clippy::extern_without_abi)]
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5+
extern crate proc_macros;
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use proc_macros::{external, with_span};
7+
8+
#[rustfmt::skip]
9+
extern fn foo() {}
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//~^ ERROR: `extern` missing explicit ABI
11+
12+
#[rustfmt::skip]
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extern
14+
fn foo_two() {}
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//~^^ ERROR: `extern` missing explicit ABI
16+
17+
extern "C" fn bar() {}
18+
19+
#[rustfmt::skip]
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extern
21+
"C"
22+
fn bar_two() {}
23+
24+
extern "system" fn baz() {}
25+
26+
#[rustfmt::skip]
27+
extern {
28+
//~^ ERROR: `extern` missing explicit ABI
29+
fn qux();
30+
}
31+
32+
#[rustfmt::skip]
33+
extern
34+
{
35+
//~^^ ERROR: `extern` missing explicit ABI
36+
fn qux_two();
37+
}
38+
39+
#[rustfmt::skip]
40+
extern {fn qux_three();}
41+
//~^ ERROR: `extern` missing explicit ABI
42+
43+
extern "C" {
44+
fn grault();
45+
}
46+
47+
extern "system" {
48+
fn grault_two();
49+
}
50+
51+
external! {
52+
extern fn waldo() {}
53+
}
54+
55+
with_span! {
56+
span
57+
extern fn waldo_two() {}
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}
59+
60+
fn main() {}

‎tests/ui/extern_without_abi.stderr

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error: `extern` missing explicit ABI
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--> tests/ui/extern_without_abi.rs:9:1
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|
4+
LL | extern fn foo() {}
5+
| ^^^^^^^^^^^^^^^^^^ help: consider using: `extern "C" fn foo() {}`
6+
|
7+
= note: `-D clippy::extern-without-abi` implied by `-D warnings`
8+
= help: to override `-D warnings` add `#[allow(clippy::extern_without_abi)]`
9+
10+
error: `extern` missing explicit ABI
11+
--> tests/ui/extern_without_abi.rs:13:1
12+
|
13+
LL | / extern
14+
LL | | fn foo_two() {}
15+
| |_______________^
16+
|
17+
help: consider using
18+
|
19+
LL ~ extern "C"
20+
LL + fn foo_two() {}
21+
|
22+
23+
error: `extern` missing explicit ABI
24+
--> tests/ui/extern_without_abi.rs:27:1
25+
|
26+
LL | / extern {
27+
LL | |
28+
LL | | fn qux();
29+
LL | | }
30+
| |_^
31+
|
32+
help: consider using
33+
|
34+
LL + extern "C" {
35+
LL +
36+
LL + fn qux();
37+
LL + }
38+
|
39+
40+
error: `extern` missing explicit ABI
41+
--> tests/ui/extern_without_abi.rs:33:1
42+
|
43+
LL | / extern
44+
LL | | {
45+
LL | |
46+
LL | | fn qux_two();
47+
LL | | }
48+
| |_^
49+
|
50+
help: consider using
51+
|
52+
LL ~ extern "C"
53+
LL + {
54+
LL +
55+
LL + fn qux_two();
56+
LL + }
57+
|
58+
59+
error: `extern` missing explicit ABI
60+
--> tests/ui/extern_without_abi.rs:40:1
61+
|
62+
LL | extern {fn qux_three();}
63+
| ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `extern "C" {fn qux_three();}`
64+
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error: aborting due to 5 previous errors
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