62 lines
1.8 KiB
Rust
62 lines
1.8 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::source::snippet;
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use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item};
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir::{Expr, ExprKind, LangItem};
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use rustc_lint::LateContext;
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use rustc_span::sym;
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use super::MATCH_ON_VEC_ITEMS;
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pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, scrutinee: &'tcx Expr<'_>) {
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if_chain! {
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if let Some(idx_expr) = is_vec_indexing(cx, scrutinee);
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if let ExprKind::Index(vec, idx) = idx_expr.kind;
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then {
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// FIXME: could be improved to suggest surrounding every pattern with Some(_),
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// but only when `or_patterns` are stabilized.
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span_lint_and_sugg(
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cx,
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MATCH_ON_VEC_ITEMS,
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scrutinee.span,
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"indexing into a vector may panic",
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"try this",
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format!(
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"{}.get({})",
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snippet(cx, vec.span, ".."),
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snippet(cx, idx.span, "..")
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),
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Applicability::MaybeIncorrect
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);
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}
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}
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}
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fn is_vec_indexing<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
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if_chain! {
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if let ExprKind::Index(array, index) = expr.kind;
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if is_vector(cx, array);
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if !is_full_range(cx, index);
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then {
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return Some(expr);
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}
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}
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None
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}
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fn is_vector(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
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let ty = cx.typeck_results().expr_ty(expr);
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let ty = ty.peel_refs();
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is_type_diagnostic_item(cx, ty, sym::Vec)
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}
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fn is_full_range(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
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let ty = cx.typeck_results().expr_ty(expr);
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let ty = ty.peel_refs();
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is_type_lang_item(cx, ty, LangItem::RangeFull)
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}
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