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Move the unused extern crate check back to the resolver.
This commit is contained in:
parent
b869e84e58
commit
958419d354
@ -1,12 +1,8 @@
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use crate::errors::{ExternCrateNotIdiomatic, UnusedExternCrate};
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use rustc_data_structures::fx::FxHashMap;
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use rustc_data_structures::unord::UnordSet;
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use rustc_hir as hir;
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use rustc_hir::def::DefKind;
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use rustc_hir::def_id::{DefId, LocalDefId};
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use rustc_hir::def_id::LocalDefId;
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use rustc_middle::ty::TyCtxt;
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use rustc_session::lint;
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use rustc_span::{Span, Symbol};
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pub fn check_crate(tcx: TyCtxt<'_>) {
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let mut used_trait_imports: UnordSet<LocalDefId> = Default::default();
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@ -43,131 +39,4 @@ pub fn check_crate(tcx: TyCtxt<'_>) {
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|lint| lint,
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);
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}
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unused_crates_lint(tcx);
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}
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fn unused_crates_lint(tcx: TyCtxt<'_>) {
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let lint = lint::builtin::UNUSED_EXTERN_CRATES;
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// Collect first the crates that are completely unused. These we
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// can always suggest removing (no matter which edition we are
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// in).
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let unused_extern_crates: FxHashMap<LocalDefId, Span> = tcx
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.maybe_unused_extern_crates(())
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.iter()
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.filter(|&&(def_id, _)| {
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tcx.extern_mod_stmt_cnum(def_id).map_or(true, |cnum| {
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!tcx.is_compiler_builtins(cnum)
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&& !tcx.is_panic_runtime(cnum)
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&& !tcx.has_global_allocator(cnum)
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&& !tcx.has_panic_handler(cnum)
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})
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})
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.cloned()
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.collect();
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// Collect all the extern crates (in a reliable order).
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let mut crates_to_lint = vec![];
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for id in tcx.hir().items() {
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if matches!(tcx.def_kind(id.owner_id), DefKind::ExternCrate) {
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let item = tcx.hir().item(id);
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if let hir::ItemKind::ExternCrate(orig_name) = item.kind {
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crates_to_lint.push(ExternCrateToLint {
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def_id: item.owner_id.to_def_id(),
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span: item.span,
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orig_name,
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warn_if_unused: !item.ident.as_str().starts_with('_'),
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});
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}
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}
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}
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let extern_prelude = &tcx.resolutions(()).extern_prelude;
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for extern_crate in &crates_to_lint {
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let def_id = extern_crate.def_id.expect_local();
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let item = tcx.hir().expect_item(def_id);
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// If the crate is fully unused, we suggest removing it altogether.
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// We do this in any edition.
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if extern_crate.warn_if_unused {
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if let Some(&span) = unused_extern_crates.get(&def_id) {
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// Removal suggestion span needs to include attributes (Issue #54400)
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let id = tcx.hir().local_def_id_to_hir_id(def_id);
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let span_with_attrs = tcx
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.hir()
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.attrs(id)
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.iter()
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.map(|attr| attr.span)
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.fold(span, |acc, attr_span| acc.to(attr_span));
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tcx.emit_spanned_lint(lint, id, span, UnusedExternCrate { span: span_with_attrs });
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continue;
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}
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}
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// If we are not in Rust 2018 edition, then we don't make any further
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// suggestions.
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if !tcx.sess.rust_2018() {
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continue;
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}
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// If the extern crate isn't in the extern prelude,
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// there is no way it can be written as a `use`.
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let orig_name = extern_crate.orig_name.unwrap_or(item.ident.name);
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if !extern_prelude.get(&orig_name).map_or(false, |from_item| !from_item) {
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continue;
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}
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// If the extern crate is renamed, then we cannot suggest replacing it with a use as this
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// would not insert the new name into the prelude, where other imports in the crate may be
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// expecting it.
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if extern_crate.orig_name.is_some() {
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continue;
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}
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let id = tcx.hir().local_def_id_to_hir_id(def_id);
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// If the extern crate has any attributes, they may have funky
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// semantics we can't faithfully represent using `use` (most
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// notably `#[macro_use]`). Ignore it.
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if !tcx.hir().attrs(id).is_empty() {
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continue;
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}
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let base_replacement = match extern_crate.orig_name {
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Some(orig_name) => format!("use {} as {};", orig_name, item.ident.name),
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None => format!("use {};", item.ident.name),
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};
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let vis = tcx.sess.source_map().span_to_snippet(item.vis_span).unwrap_or_default();
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let add_vis = |to| if vis.is_empty() { to } else { format!("{} {}", vis, to) };
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tcx.emit_spanned_lint(
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lint,
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id,
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extern_crate.span,
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ExternCrateNotIdiomatic {
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span: extern_crate.span,
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msg_code: add_vis("use".to_string()),
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suggestion_code: add_vis(base_replacement),
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},
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);
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}
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}
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struct ExternCrateToLint {
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/// `DefId` of the extern crate
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def_id: DefId,
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/// span from the item
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span: Span,
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/// if `Some`, then this is renamed (`extern crate orig_name as
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/// crate_name`), and -- perhaps surprisingly -- this stores the
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/// *original* name (`item.name` will contain the new name)
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orig_name: Option<Symbol>,
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/// if `false`, the original name started with `_`, so we shouldn't lint
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/// about it going unused (but we should still emit idiom lints).
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warn_if_unused: bool,
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}
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@ -5,7 +5,7 @@ use rustc_errors::{
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error_code, Applicability, DiagnosticBuilder, ErrorGuaranteed, Handler, IntoDiagnostic,
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MultiSpan,
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};
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use rustc_macros::{Diagnostic, LintDiagnostic};
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use rustc_macros::Diagnostic;
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use rustc_middle::ty::Ty;
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use rustc_span::{symbol::Ident, Span, Symbol};
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@ -247,26 +247,6 @@ pub struct SubstsOnOverriddenImpl {
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pub span: Span,
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}
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#[derive(LintDiagnostic)]
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#[diag(hir_analysis_unused_extern_crate)]
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pub struct UnusedExternCrate {
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#[suggestion(applicability = "machine-applicable", code = "")]
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pub span: Span,
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}
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#[derive(LintDiagnostic)]
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#[diag(hir_analysis_extern_crate_not_idiomatic)]
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pub struct ExternCrateNotIdiomatic {
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#[suggestion(
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style = "short",
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applicability = "machine-applicable",
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code = "{suggestion_code}"
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)]
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pub span: Span,
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pub msg_code: String,
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pub suggestion_code: String,
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}
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#[derive(Diagnostic)]
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#[diag(hir_analysis_const_impl_for_non_const_trait)]
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pub struct ConstImplForNonConstTrait {
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@ -893,6 +893,23 @@ pub trait LintContext: Sized {
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BuiltinLintDiagnostics::ByteSliceInPackedStructWithDerive => {
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db.help("consider implementing the trait by hand, or remove the `packed` attribute");
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}
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BuiltinLintDiagnostics::UnusedExternCrate { removal_span }=> {
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db.span_suggestion(
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removal_span,
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"remove it",
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"",
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Applicability::MachineApplicable,
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);
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}
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BuiltinLintDiagnostics::ExternCrateNotIdiomatic { vis_span, ident_span }=> {
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let suggestion_span = vis_span.between(ident_span);
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db.span_suggestion_verbose(
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suggestion_span,
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"convert it to a `use`",
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if vis_span.is_empty() { "use " } else { " use " },
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Applicability::MachineApplicable,
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);
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}
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}
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// Rewrap `db`, and pass control to the user.
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decorate(db)
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@ -522,6 +522,13 @@ pub enum BuiltinLintDiagnostics {
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is_formatting_arg: bool,
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},
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ByteSliceInPackedStructWithDerive,
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UnusedExternCrate {
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removal_span: Span,
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},
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ExternCrateNotIdiomatic {
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vis_span: Span,
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ident_span: Span,
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},
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}
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/// Lints that are buffered up early on in the `Session` before the
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@ -29,11 +29,12 @@ use crate::Resolver;
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use rustc_ast as ast;
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use rustc_ast::visit::{self, Visitor};
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use rustc_data_structures::fx::FxIndexMap;
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use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
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use rustc_data_structures::unord::UnordSet;
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use rustc_errors::{pluralize, MultiSpan};
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use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_IMPORTS};
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use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_EXTERN_CRATES, UNUSED_IMPORTS};
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use rustc_session::lint::BuiltinLintDiagnostics;
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use rustc_span::symbol::{Ident, Symbol};
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use rustc_span::{Span, DUMMY_SP};
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struct UnusedImport<'a> {
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@ -53,11 +54,30 @@ struct UnusedImportCheckVisitor<'a, 'b, 'tcx> {
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r: &'a mut Resolver<'b, 'tcx>,
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/// All the (so far) unused imports, grouped path list
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unused_imports: FxIndexMap<ast::NodeId, UnusedImport<'a>>,
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extern_crate_items: Vec<ExternCrateToLint>,
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base_use_tree: Option<&'a ast::UseTree>,
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base_id: ast::NodeId,
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item_span: Span,
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}
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struct ExternCrateToLint {
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id: ast::NodeId,
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/// Span from the item
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span: Span,
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/// Span to use to suggest complete removal.
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span_with_attributes: Span,
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/// Span of the visibility, if any.
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vis_span: Span,
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/// Whether the item has attrs.
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has_attrs: bool,
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/// Name used to refer to the crate.
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ident: Ident,
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/// If `Some`, then this is renamed (`extern crate orig_name as
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/// crate_name`), and -- perhaps surprisingly -- this stores the
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/// *original* name (`item.name` will contain the new name)
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orig_name: Option<Symbol>,
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}
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impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
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// We have information about whether `use` (import) items are actually
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// used now. If an import is not used at all, we signal a lint error.
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@ -96,18 +116,27 @@ impl<'a, 'b, 'tcx> UnusedImportCheckVisitor<'a, 'b, 'tcx> {
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impl<'a, 'b, 'tcx> Visitor<'a> for UnusedImportCheckVisitor<'a, 'b, 'tcx> {
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fn visit_item(&mut self, item: &'a ast::Item) {
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self.item_span = item.span_with_attributes();
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// Ignore is_public import statements because there's no way to be sure
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// whether they're used or not. Also ignore imports with a dummy span
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// because this means that they were generated in some fashion by the
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// compiler and we don't need to consider them.
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if let ast::ItemKind::Use(..) = item.kind {
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if item.vis.kind.is_pub() || item.span.is_dummy() {
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return;
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match item.kind {
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// Ignore is_public import statements because there's no way to be sure
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// whether they're used or not. Also ignore imports with a dummy span
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// because this means that they were generated in some fashion by the
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// compiler and we don't need to consider them.
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ast::ItemKind::Use(..) if item.vis.kind.is_pub() || item.span.is_dummy() => return,
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ast::ItemKind::ExternCrate(orig_name) => {
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self.extern_crate_items.push(ExternCrateToLint {
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id: item.id,
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span: item.span,
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vis_span: item.vis.span,
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span_with_attributes: item.span_with_attributes(),
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has_attrs: !item.attrs.is_empty(),
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ident: item.ident,
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orig_name,
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});
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}
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_ => {}
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}
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self.item_span = item.span_with_attributes();
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visit::walk_item(self, item);
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}
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@ -224,6 +253,9 @@ fn calc_unused_spans(
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impl Resolver<'_, '_> {
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pub(crate) fn check_unused(&mut self, krate: &ast::Crate) {
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let tcx = self.tcx;
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let mut maybe_unused_extern_crates = FxHashMap::default();
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for import in self.potentially_unused_imports.iter() {
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match import.kind {
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_ if import.used.get()
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@ -247,6 +279,14 @@ impl Resolver<'_, '_> {
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ImportKind::ExternCrate { id, .. } => {
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let def_id = self.local_def_id(id);
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self.maybe_unused_extern_crates.push((def_id, import.span));
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if self.extern_crate_map.get(&def_id).map_or(true, |&cnum| {
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!tcx.is_compiler_builtins(cnum)
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&& !tcx.is_panic_runtime(cnum)
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&& !tcx.has_global_allocator(cnum)
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&& !tcx.has_panic_handler(cnum)
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}) {
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maybe_unused_extern_crates.insert(id, import.span);
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}
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}
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ImportKind::MacroUse => {
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let msg = "unused `#[macro_use]` import";
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@ -259,6 +299,7 @@ impl Resolver<'_, '_> {
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let mut visitor = UnusedImportCheckVisitor {
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r: self,
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unused_imports: Default::default(),
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extern_crate_items: Default::default(),
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base_use_tree: None,
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base_id: ast::DUMMY_NODE_ID,
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item_span: DUMMY_SP,
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@ -290,7 +331,7 @@ impl Resolver<'_, '_> {
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let ms = MultiSpan::from_spans(spans.clone());
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let mut span_snippets = spans
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.iter()
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.filter_map(|s| match visitor.r.tcx.sess.source_map().span_to_snippet(*s) {
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.filter_map(|s| match tcx.sess.source_map().span_to_snippet(*s) {
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Ok(s) => Some(format!("`{}`", s)),
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_ => None,
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})
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@ -317,7 +358,7 @@ impl Resolver<'_, '_> {
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// If we are in the `--test` mode, suppress a help that adds the `#[cfg(test)]`
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// attribute; however, if not, suggest adding the attribute. There is no way to
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// retrieve attributes here because we do not have a `TyCtxt` yet.
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let test_module_span = if visitor.r.tcx.sess.opts.test {
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let test_module_span = if tcx.sess.opts.test {
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None
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} else {
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let parent_module = visitor.r.get_nearest_non_block_module(
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@ -346,5 +387,76 @@ impl Resolver<'_, '_> {
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BuiltinLintDiagnostics::UnusedImports(fix_msg.into(), fixes, test_module_span),
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);
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}
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for extern_crate in visitor.extern_crate_items {
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let warn_if_unused = !extern_crate.ident.name.as_str().starts_with('_');
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// If the crate is fully unused, we suggest removing it altogether.
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// We do this in any edition.
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if warn_if_unused {
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if let Some(&span) = maybe_unused_extern_crates.get(&extern_crate.id) {
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visitor.r.lint_buffer.buffer_lint_with_diagnostic(
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UNUSED_EXTERN_CRATES,
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extern_crate.id,
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span,
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"unused extern crate",
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BuiltinLintDiagnostics::UnusedExternCrate {
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removal_span: extern_crate.span_with_attributes,
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},
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);
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continue;
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}
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}
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// If we are not in Rust 2018 edition, then we don't make any further
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// suggestions.
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if !tcx.sess.rust_2018() {
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continue;
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}
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// If the extern crate has any attributes, they may have funky
|
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// semantics we can't faithfully represent using `use` (most
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// notably `#[macro_use]`). Ignore it.
|
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if extern_crate.has_attrs {
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continue;
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}
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|
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// If the extern crate is renamed, then we cannot suggest replacing it with a use as this
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// would not insert the new name into the prelude, where other imports in the crate may be
|
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// expecting it.
|
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if extern_crate.orig_name.is_some() {
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continue;
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}
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// If the extern crate isn't in the extern prelude,
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// there is no way it can be written as a `use`.
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let usage_name =
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extern_crate.orig_name.map_or(extern_crate.ident, Ident::with_dummy_span);
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if !visitor
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.r
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.extern_prelude
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.get(&usage_name)
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.map_or(false, |entry| !entry.introduced_by_item)
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{
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continue;
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}
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let vis_span = extern_crate
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.vis_span
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.find_ancestor_inside(extern_crate.span)
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.unwrap_or(extern_crate.vis_span);
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let ident_span = extern_crate
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.ident
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.span
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.find_ancestor_inside(extern_crate.span)
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.unwrap_or(extern_crate.ident.span);
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visitor.r.lint_buffer.buffer_lint_with_diagnostic(
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UNUSED_EXTERN_CRATES,
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extern_crate.id,
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extern_crate.span,
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"`extern crate` is not idiomatic in the new edition",
|
||||
BuiltinLintDiagnostics::ExternCrateNotIdiomatic { vis_span, ident_span },
|
||||
);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
@ -23,6 +23,7 @@ extern crate alloc;
|
||||
fn main() {
|
||||
another_name::mem::drop(3);
|
||||
another::foo();
|
||||
with_visibility::foo();
|
||||
remove_extern_crate::foo!();
|
||||
bar!();
|
||||
alloc::vec![5];
|
||||
@ -37,3 +38,12 @@ mod another {
|
||||
remove_extern_crate::foo!();
|
||||
}
|
||||
}
|
||||
|
||||
mod with_visibility {
|
||||
pub use core; //~ WARNING `extern crate` is not idiomatic
|
||||
|
||||
pub fn foo() {
|
||||
core::mem::drop(4);
|
||||
remove_extern_crate::foo!();
|
||||
}
|
||||
}
|
||||
|
@ -23,6 +23,7 @@ extern crate alloc;
|
||||
fn main() {
|
||||
another_name::mem::drop(3);
|
||||
another::foo();
|
||||
with_visibility::foo();
|
||||
remove_extern_crate::foo!();
|
||||
bar!();
|
||||
alloc::vec![5];
|
||||
@ -37,3 +38,12 @@ mod another {
|
||||
remove_extern_crate::foo!();
|
||||
}
|
||||
}
|
||||
|
||||
mod with_visibility {
|
||||
pub extern crate core; //~ WARNING `extern crate` is not idiomatic
|
||||
|
||||
pub fn foo() {
|
||||
core::mem::drop(4);
|
||||
remove_extern_crate::foo!();
|
||||
}
|
||||
}
|
||||
|
@ -12,10 +12,26 @@ LL | #![warn(rust_2018_idioms)]
|
||||
= note: `#[warn(unused_extern_crates)]` implied by `#[warn(rust_2018_idioms)]`
|
||||
|
||||
warning: `extern crate` is not idiomatic in the new edition
|
||||
--> $DIR/remove-extern-crate.rs:32:5
|
||||
--> $DIR/remove-extern-crate.rs:33:5
|
||||
|
|
||||
LL | extern crate core;
|
||||
| ^^^^^^^^^^^^^^^^^^ help: convert it to a `use`
|
||||
| ^^^^^^^^^^^^^^^^^^
|
||||
|
|
||||
help: convert it to a `use`
|
||||
|
|
||||
LL | use core;
|
||||
| ~~~
|
||||
|
||||
warning: 2 warnings emitted
|
||||
warning: `extern crate` is not idiomatic in the new edition
|
||||
--> $DIR/remove-extern-crate.rs:43:5
|
||||
|
|
||||
LL | pub extern crate core;
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^
|
||||
|
|
||||
help: convert it to a `use`
|
||||
|
|
||||
LL | pub use core;
|
||||
| ~~~
|
||||
|
||||
warning: 3 warnings emitted
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user