//! lint on indexing and slicing operations
-use crate::consts::{constant, Constant};
-use crate::utils::{higher, span_lint, span_lint_and_help};
+use clippy_utils::consts::{constant, Constant};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
+use clippy_utils::higher;
use rustc_ast::ast::RangeLimits;
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
- /// **What it does:** Checks for out of bounds array indexing with a constant
+ /// ### What it does
+ /// Checks for out of bounds array indexing with a constant
/// index.
///
- /// **Why is this bad?** This will always panic at runtime.
+ /// ### Why is this bad?
+ /// This will always panic at runtime.
///
- /// **Known problems:** Hopefully none.
+ /// ### Known problems
+ /// Hopefully none.
///
- /// **Example:**
+ /// ### Example
/// ```no_run
/// # #![allow(const_err)]
/// let x = [1, 2, 3, 4];
/// x[0];
/// x[3];
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub OUT_OF_BOUNDS_INDEXING,
correctness,
"out of bounds constant indexing"
}
declare_clippy_lint! {
- /// **What it does:** Checks for usage of indexing or slicing. Arrays are special cases, this lint
+ /// ### What it does
+ /// Checks for usage of indexing or slicing. Arrays are special cases, this lint
/// does report on arrays if we can tell that slicing operations are in bounds and does not
/// lint on constant `usize` indexing on arrays because that is handled by rustc's `const_err` lint.
///
- /// **Why is this bad?** Indexing and slicing can panic at runtime and there are
+ /// ### Why is this bad?
+ /// Indexing and slicing can panic at runtime and there are
/// safe alternatives.
///
- /// **Known problems:** Hopefully none.
+ /// ### Known problems
+ /// Hopefully none.
///
- /// **Example:**
+ /// ### Example
/// ```rust,no_run
/// // Vector
/// let x = vec![0; 5];
/// y.get(10..);
/// y.get(..100);
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub INDEXING_SLICING,
restriction,
"indexing/slicing usage"
declare_lint_pass!(IndexingSlicing => [INDEXING_SLICING, OUT_OF_BOUNDS_INDEXING]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for IndexingSlicing {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
- if let ExprKind::Index(ref array, ref index) = &expr.kind {
- let ty = cx.tables().expr_ty(array);
- if let Some(range) = higher::range(cx, index) {
+impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+ if cx.tcx.hir().is_inside_const_context(expr.hir_id) {
+ return;
+ }
+
+ if let ExprKind::Index(array, index) = &expr.kind {
+ let ty = cx.typeck_results().expr_ty(array).peel_refs();
+ if let Some(range) = higher::Range::hir(index) {
// Ranged indexes, i.e., &x[n..m], &x[n..], &x[..n] and &x[..]
- if let ty::Array(_, s) = ty.kind {
+ if let ty::Array(_, s) = ty.kind() {
let size: u128 = if let Some(size) = s.try_eval_usize(cx.tcx, cx.param_env) {
size.into()
} else {
}
let help_msg = match (range.start, range.end) {
- (None, Some(_)) => "Consider using `.get(..n)`or `.get_mut(..n)` instead",
- (Some(_), None) => "Consider using `.get(n..)` or .get_mut(n..)` instead",
- (Some(_), Some(_)) => "Consider using `.get(n..m)` or `.get_mut(n..m)` instead",
+ (None, Some(_)) => "consider using `.get(..n)`or `.get_mut(..n)` instead",
+ (Some(_), None) => "consider using `.get(n..)` or .get_mut(n..)` instead",
+ (Some(_), Some(_)) => "consider using `.get(n..m)` or `.get_mut(n..m)` instead",
(None, None) => return, // [..] is ok.
};
- span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic.", None, help_msg);
+ span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic", None, help_msg);
} else {
// Catchall non-range index, i.e., [n] or [n << m]
- if let ty::Array(..) = ty.kind {
+ if let ty::Array(..) = ty.kind() {
+ // Index is a const block.
+ if let ExprKind::ConstBlock(..) = index.kind {
+ return;
+ }
// Index is a constant uint.
- if let Some(..) = constant(cx, cx.tables(), index) {
+ if let Some(..) = constant(cx, cx.typeck_results(), index) {
// Let rustc's `const_err` lint handle constant `usize` indexing on arrays.
return;
}
cx,
INDEXING_SLICING,
expr.span,
- "indexing may panic.",
+ "indexing may panic",
None,
- "Consider using `.get(n)` or `.get_mut(n)` instead",
+ "consider using `.get(n)` or `.get_mut(n)` instead",
);
}
}
/// Returns a tuple of options with the start and end (exclusive) values of
/// the range. If the start or end is not constant, None is returned.
-fn to_const_range<'a, 'tcx>(
- cx: &LateContext<'a, 'tcx>,
+fn to_const_range<'tcx>(
+ cx: &LateContext<'tcx>,
range: higher::Range<'_>,
array_size: u128,
) -> (Option<u128>, Option<u128>) {
- let s = range.start.map(|expr| constant(cx, cx.tables(), expr).map(|(c, _)| c));
+ let s = range
+ .start
+ .map(|expr| constant(cx, cx.typeck_results(), expr).map(|(c, _)| c));
let start = match s {
Some(Some(Constant::Int(x))) => Some(x),
Some(_) => None,
None => Some(0),
};
- let e = range.end.map(|expr| constant(cx, cx.tables(), expr).map(|(c, _)| c));
+ let e = range
+ .end
+ .map(|expr| constant(cx, cx.typeck_results(), expr).map(|(c, _)| c));
let end = match e {
Some(Some(Constant::Int(x))) => {
if range.limits == RangeLimits::Closed {
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