31 lines
1.1 KiB
Rust
31 lines
1.1 KiB
Rust
use clippy_utils::consts::{constant, Constant};
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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::is_trait_method;
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use clippy_utils::source::snippet_with_applicability;
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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use rustc_lint::LateContext;
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use rustc_span::sym;
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use super::ITER_NTH_ZERO;
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pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
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if_chain! {
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if is_trait_method(cx, expr, sym::Iterator);
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if let Some((Constant::Int(0), _)) = constant(cx, cx.typeck_results(), arg);
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then {
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let mut applicability = Applicability::MachineApplicable;
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span_lint_and_sugg(
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cx,
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ITER_NTH_ZERO,
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expr.span,
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"called `.nth(0)` on a `std::iter::Iterator`, when `.next()` is equivalent",
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"try calling `.next()` instead of `.nth(0)`",
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format!("{}.next()", snippet_with_applicability(cx, recv.span, "..", &mut applicability)),
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applicability,
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);
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}
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}
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}
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