71 lines
2.7 KiB
Rust
71 lines
2.7 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_then;
|
|
use if_chain::if_chain;
|
|
use rustc_ast::{Item, ItemKind, UseTreeKind};
|
|
use rustc_errors::Applicability;
|
|
use rustc_lint::{EarlyContext, EarlyLintPass};
|
|
use rustc_session::{declare_lint_pass, declare_tool_lint};
|
|
use rustc_span::symbol::kw;
|
|
|
|
declare_clippy_lint! {
|
|
/// ### What it does
|
|
/// Checks for imports ending in `::{self}`.
|
|
///
|
|
/// ### Why is this bad?
|
|
/// In most cases, this can be written much more cleanly by omitting `::{self}`.
|
|
///
|
|
/// ### Known problems
|
|
/// Removing `::{self}` will cause any non-module items at the same path to also be imported.
|
|
/// This might cause a naming conflict (https://github.com/rust-lang/rustfmt/issues/3568). This lint makes no attempt
|
|
/// to detect this scenario and that is why it is a restriction lint.
|
|
///
|
|
/// ### Example
|
|
/// ```rust
|
|
/// use std::io::{self};
|
|
/// ```
|
|
/// Use instead:
|
|
/// ```rust
|
|
/// use std::io;
|
|
/// ```
|
|
#[clippy::version = "1.53.0"]
|
|
pub UNNECESSARY_SELF_IMPORTS,
|
|
restriction,
|
|
"imports ending in `::{self}`, which can be omitted"
|
|
}
|
|
|
|
declare_lint_pass!(UnnecessarySelfImports => [UNNECESSARY_SELF_IMPORTS]);
|
|
|
|
impl EarlyLintPass for UnnecessarySelfImports {
|
|
fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
|
|
if_chain! {
|
|
if let ItemKind::Use(use_tree) = &item.kind;
|
|
if let UseTreeKind::Nested(nodes) = &use_tree.kind;
|
|
if let [(self_tree, _)] = &**nodes;
|
|
if let [self_seg] = &*self_tree.prefix.segments;
|
|
if self_seg.ident.name == kw::SelfLower;
|
|
if let Some(last_segment) = use_tree.prefix.segments.last();
|
|
|
|
then {
|
|
span_lint_and_then(
|
|
cx,
|
|
UNNECESSARY_SELF_IMPORTS,
|
|
item.span,
|
|
"import ending with `::{self}`",
|
|
|diag| {
|
|
diag.span_suggestion(
|
|
last_segment.span().with_hi(item.span.hi()),
|
|
"consider omitting `::{self}`",
|
|
format!(
|
|
"{}{};",
|
|
last_segment.ident,
|
|
if let UseTreeKind::Simple(Some(alias), ..) = self_tree.kind { format!(" as {}", alias) } else { String::new() },
|
|
),
|
|
Applicability::MaybeIncorrect,
|
|
);
|
|
diag.note("this will slightly change semantics; any non-module items at the same path will also be imported");
|
|
},
|
|
);
|
|
}
|
|
}
|
|
}
|
|
}
|