-use crate::utils::{is_type_diagnostic_item, snippet_with_applicability, span_lint_and_sugg, walk_ptrs_ty};
+use crate::utils::{is_type_diagnostic_item, is_type_lang_item, snippet, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, MatchSource};
+use rustc_hir::{Expr, ExprKind, LangItem, MatchSource};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
declare_clippy_lint! {
/// **What it does:** Checks for `match vec[idx]` or `match vec[n..m]`.
/// }
/// ```
pub MATCH_ON_VEC_ITEMS,
- style,
+ pedantic,
"matching on vector elements can panic"
}
declare_lint_pass!(MatchOnVecItems => [MATCH_ON_VEC_ITEMS]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MatchOnVecItems {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'tcx>) {
+impl<'tcx> LateLintPass<'tcx> for MatchOnVecItems {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
if_chain! {
if !in_external_macro(cx.sess(), expr.span);
if let ExprKind::Match(ref match_expr, _, MatchSource::Normal) = expr.kind;
if let ExprKind::Index(vec, idx) = idx_expr.kind;
then {
- let mut applicability = Applicability::MaybeIncorrect;
+ // FIXME: could be improved to suggest surrounding every pattern with Some(_),
+ // but only when `or_patterns` are stabilized.
span_lint_and_sugg(
cx,
MATCH_ON_VEC_ITEMS,
match_expr.span,
- "indexing vector may panic. Consider using `get`",
+ "indexing into a vector may panic",
"try this",
format!(
"{}.get({})",
- snippet_with_applicability(cx, vec.span, "..", &mut applicability),
- snippet_with_applicability(cx, idx.span, "..", &mut applicability)
+ snippet(cx, vec.span, ".."),
+ snippet(cx, idx.span, "..")
),
- applicability
+ Applicability::MaybeIncorrect
);
}
}
}
}
-fn is_vec_indexing<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
+fn is_vec_indexing<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
if_chain! {
- if let ExprKind::Index(ref array, _) = expr.kind;
- let ty = cx.tables.expr_ty(array);
- let ty = walk_ptrs_ty(ty);
- if is_type_diagnostic_item(cx, ty, sym!(vec_type));
+ if let ExprKind::Index(ref array, ref index) = expr.kind;
+ if is_vector(cx, array);
+ if !is_full_range(cx, index);
then {
return Some(expr);
None
}
+
+fn is_vector(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ let ty = cx.typeck_results().expr_ty(expr);
+ let ty = ty.peel_refs();
+ is_type_diagnostic_item(cx, ty, sym::vec_type)
+}
+
+fn is_full_range(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
+ let ty = cx.typeck_results().expr_ty(expr);
+ let ty = ty.peel_refs();
+ is_type_lang_item(cx, ty, LangItem::RangeFull)
+}