40 lines
1.2 KiB
Rust
40 lines
1.2 KiB
Rust
use super::utils::derefs_to_slice;
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use crate::methods::iter_nth_zero;
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use clippy_utils::diagnostics::span_lint_and_help;
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use clippy_utils::ty::is_type_diagnostic_item;
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use rustc_hir as hir;
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use rustc_lint::LateContext;
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use rustc_span::symbol::sym;
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use super::ITER_NTH;
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pub(super) fn check<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &hir::Expr<'_>,
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iter_recv: &'tcx hir::Expr<'tcx>,
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nth_recv: &hir::Expr<'_>,
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nth_arg: &hir::Expr<'_>,
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is_mut: bool,
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) {
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let mut_str = if is_mut { "_mut" } else { "" };
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let caller_type = if derefs_to_slice(cx, iter_recv, cx.typeck_results().expr_ty(iter_recv)).is_some() {
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"slice"
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} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(iter_recv), sym::Vec) {
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"Vec"
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} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(iter_recv), sym::VecDeque) {
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"VecDeque"
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} else {
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iter_nth_zero::check(cx, expr, nth_recv, nth_arg);
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return; // caller is not a type that we want to lint
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};
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span_lint_and_help(
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cx,
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ITER_NTH,
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expr.span,
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&format!("called `.iter{mut_str}().nth()` on a {caller_type}"),
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None,
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&format!("calling `.get{mut_str}()` is both faster and more readable"),
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);
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}
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