63 lines
2.0 KiB
Rust
63 lines
2.0 KiB
Rust
use crate::utils::{in_macro, span_lint_and_sugg};
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use if_chain::if_chain;
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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, declare_tool_lint};
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use rustc_span::edition::Edition;
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declare_clippy_lint! {
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/// **What it does:** Checking for imports with single component use path.
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///
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/// **Why is this bad?** Import with single component use path such as `use cratename;`
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/// is not necessary, and thus should be removed.
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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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/// use regex;
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///
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/// fn main() {
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/// regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
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/// }
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/// ```
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/// Better as
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/// ```rust,ignore
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/// fn main() {
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/// regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap();
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/// }
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/// ```
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pub SINGLE_COMPONENT_PATH_IMPORTS,
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style,
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"imports with single component path are redundant"
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}
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declare_lint_pass!(SingleComponentPathImports => [SINGLE_COMPONENT_PATH_IMPORTS]);
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impl EarlyLintPass for SingleComponentPathImports {
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fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
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if_chain! {
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if !in_macro(item.span);
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if cx.sess.opts.edition >= Edition::Edition2018;
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if !item.vis.kind.is_pub();
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if let ItemKind::Use(use_tree) = &item.kind;
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if let segments = &use_tree.prefix.segments;
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if segments.len() == 1;
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if let UseTreeKind::Simple(None, _, _) = use_tree.kind;
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then {
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span_lint_and_sugg(
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cx,
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SINGLE_COMPONENT_PATH_IMPORTS,
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item.span,
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"this import is redundant",
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"remove it entirely",
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String::new(),
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Applicability::MachineApplicable
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);
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}
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}
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}
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}
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