81 lines
2.7 KiB
Rust
81 lines
2.7 KiB
Rust
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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::in_macro;
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use clippy_utils::source::snippet_with_applicability;
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use rustc_errors::Applicability;
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use rustc_hir::{Expr, ExprKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use std::borrow::Cow;
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use std::cmp::Reverse;
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use std::collections::BinaryHeap;
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for tuple structs initialized with field syntax.
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/// It will however not lint if a base initializer is present.
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/// The lint will also ignore code in macros.
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///
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/// ### Why is this bad?
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/// This may be confusing to the uninitiated and adds no
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/// benefit as opposed to tuple initializers
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///
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/// ### Example
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/// ```rust
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/// struct TupleStruct(u8, u16);
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///
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/// let _ = TupleStruct {
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/// 0: 1,
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/// 1: 23,
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/// };
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///
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/// // should be written as
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/// let base = TupleStruct(1, 23);
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///
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/// // This is OK however
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/// let _ = TupleStruct { 0: 42, ..base };
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/// ```
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#[clippy::version = "1.59.0"]
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pub INIT_NUMBERED_FIELDS,
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style,
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"numbered fields in tuple struct initializer"
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}
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declare_lint_pass!(NumberedFields => [INIT_NUMBERED_FIELDS]);
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impl<'tcx> LateLintPass<'tcx> for NumberedFields {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
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if let ExprKind::Struct(path, fields, None) = e.kind {
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if !fields.is_empty()
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&& !in_macro(e.span)
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&& fields
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.iter()
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.all(|f| f.ident.as_str().as_bytes().iter().all(u8::is_ascii_digit))
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{
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let expr_spans = fields
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.iter()
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.map(|f| (Reverse(f.ident.as_str().parse::<usize>().unwrap()), f.expr.span))
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.collect::<BinaryHeap<_>>();
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let mut appl = Applicability::MachineApplicable;
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let snippet = format!(
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"{}({})",
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snippet_with_applicability(cx, path.span(), "..", &mut appl),
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expr_spans
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.into_iter_sorted()
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.map(|(_, span)| snippet_with_applicability(cx, span, "..", &mut appl))
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.intersperse(Cow::Borrowed(", "))
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.collect::<String>()
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);
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span_lint_and_sugg(
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cx,
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INIT_NUMBERED_FIELDS,
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e.span,
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"used a field initializer for a tuple struct",
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"try this instead",
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snippet,
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appl,
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);
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}
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}
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}
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}
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