0f5338cd90
The `restriction` group contains many lints which are not about necessarily “bad” things, but style choices — perhaps even style choices which contradict conventional Rust style — or are otherwise very situational. This results in silly wording like “Why is this bad? It isn't, but ...”, which I’ve seen confuse a newcomer at least once. To improve this situation, this commit replaces the “Why is this bad?” section heading with “Why restrict this?”, for most, but not all, restriction lints. I left alone the ones whose placement in the restriction group is more incidental. In order to make this make sense, I had to remove the “It isn't, but” texts from the contents of the sections. Sometimes further changes were needed, or there were obvious fixes to make, and I went ahead and made those changes without attempting to split them into another commit, even though many of them are not strictly necessary for the “Why restrict this?” project.
71 lines
2.6 KiB
Rust
71 lines
2.6 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_then;
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use rustc_ast::{Item, ItemKind, UseTreeKind};
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use rustc_errors::Applicability;
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use rustc_lint::{EarlyContext, EarlyLintPass};
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use rustc_session::declare_lint_pass;
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use rustc_span::symbol::kw;
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for imports ending in `::{self}`.
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///
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/// ### Why restrict this?
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/// In most cases, this can be written much more cleanly by omitting `::{self}`.
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///
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/// ### Known problems
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/// Removing `::{self}` will cause any non-module items at the same path to also be imported.
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/// This might cause a naming conflict (https://github.com/rust-lang/rustfmt/issues/3568). This lint makes no attempt
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/// to detect this scenario and that is why it is a restriction lint.
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///
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/// ### Example
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/// ```no_run
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/// use std::io::{self};
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/// ```
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/// Use instead:
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/// ```no_run
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/// use std::io;
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/// ```
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#[clippy::version = "1.53.0"]
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pub UNNECESSARY_SELF_IMPORTS,
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restriction,
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"imports ending in `::{self}`, which can be omitted"
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}
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declare_lint_pass!(UnnecessarySelfImports => [UNNECESSARY_SELF_IMPORTS]);
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impl EarlyLintPass for UnnecessarySelfImports {
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fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
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if let ItemKind::Use(use_tree) = &item.kind
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&& let UseTreeKind::Nested { items, .. } = &use_tree.kind
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&& let [(self_tree, _)] = &**items
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&& let [self_seg] = &*self_tree.prefix.segments
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&& self_seg.ident.name == kw::SelfLower
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&& let Some(last_segment) = use_tree.prefix.segments.last()
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{
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span_lint_and_then(
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cx,
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UNNECESSARY_SELF_IMPORTS,
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item.span,
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"import ending with `::{self}`",
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|diag| {
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diag.span_suggestion(
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last_segment.span().with_hi(item.span.hi()),
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"consider omitting `::{self}`",
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format!(
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"{}{};",
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last_segment.ident,
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if let UseTreeKind::Simple(Some(alias)) = self_tree.kind {
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format!(" as {alias}")
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} else {
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String::new()
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},
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),
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Applicability::MaybeIncorrect,
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);
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diag.note("this will slightly change semantics; any non-module items at the same path will also be imported");
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},
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);
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}
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}
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}
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