39 lines
1.3 KiB
Rust
39 lines
1.3 KiB
Rust
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use crate::methods::derefs_to_slice;
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use crate::methods::iter_nth_zero;
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use crate::utils::{is_type_diagnostic_item, span_lint_and_help};
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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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nth_and_iter_args: &[&'tcx [hir::Expr<'tcx>]],
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is_mut: bool,
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) {
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let iter_args = nth_and_iter_args[1];
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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_args[0], cx.typeck_results().expr_ty(&iter_args[0])).is_some() {
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"slice"
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} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&iter_args[0]), sym::vec_type) {
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"Vec"
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} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&iter_args[0]), sym::vecdeque_type) {
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"VecDeque"
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} else {
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let nth_args = nth_and_iter_args[0];
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iter_nth_zero::check(cx, expr, &nth_args);
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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{0}().nth()` on a {1}", mut_str, caller_type),
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None,
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&format!("calling `.get{}()` is both faster and more readable", mut_str),
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);
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}
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