//! lint on indexing and slicing operations
use crate::consts::{constant, Constant};
-use crate::utils;
-use crate::utils::higher;
-use crate::utils::higher::Range;
-use rustc::hir::*;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::ty;
-use rustc::{declare_tool_lint, lint_array};
-use syntax::ast::RangeLimits;
+use crate::utils::{higher, span_lint, span_lint_and_help};
+use rustc_ast::ast::RangeLimits;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty;
+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
}
declare_clippy_lint! {
- /// **What it does:** Checks for usage of indexing or slicing. Arrays are special cased, 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.
///
/// **Known problems:** Hopefully none.
///
/// **Example:**
- /// ```rust
+ /// ```rust,no_run
/// // Vector
/// let x = vec![0; 5];
///
"indexing/slicing usage"
}
-#[derive(Copy, Clone)]
-pub struct IndexingSlicing;
-
-impl LintPass for IndexingSlicing {
- fn get_lints(&self) -> LintArray {
- lint_array!(INDEXING_SLICING, OUT_OF_BOUNDS_INDEXING)
- }
-
- fn name(&self) -> &'static str {
- "IndexSlicing"
- }
-}
-
-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.node {
- let ty = cx.tables.expr_ty(array);
- if let Some(range) = higher::range(cx, index) {
- // Ranged indexes, i.e. &x[n..m], &x[n..], &x[..n] and &x[..]
- if let ty::Array(_, s) = ty.sty {
- let size: u128 = s.assert_usize(cx.tcx).unwrap().into();
+declare_lint_pass!(IndexingSlicing => [INDEXING_SLICING, OUT_OF_BOUNDS_INDEXING]);
+
+impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+ if let ExprKind::Index(ref array, ref index) = &expr.kind {
+ let ty = cx.typeck_results().expr_ty(array).peel_refs();
+ if let Some(range) = higher::range(index) {
+ // Ranged indexes, i.e., &x[n..m], &x[n..], &x[..n] and &x[..]
+ 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 {
+ return;
+ };
let const_range = to_const_range(cx, range, size);
if let (Some(start), _) = const_range {
if start > size {
- utils::span_lint(
+ span_lint(
cx,
OUT_OF_BOUNDS_INDEXING,
range.start.map_or(expr.span, |start| start.span),
if let (_, Some(end)) = const_range {
if end > size {
- utils::span_lint(
+ span_lint(
cx,
OUT_OF_BOUNDS_INDEXING,
range.end.map_or(expr.span, |end| end.span),
}
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.
};
- utils::span_help_and_lint(cx, INDEXING_SLICING, expr.span, "slicing may panic.", 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.sty {
+ // Catchall non-range index, i.e., [n] or [n << m]
+ if let ty::Array(..) = ty.kind() {
// 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;
}
}
- utils::span_help_and_lint(
+ span_lint_and_help(
cx,
INDEXING_SLICING,
expr.span,
- "indexing may panic.",
- "Consider using `.get(n)` or `.get_mut(n)` instead",
+ "indexing may panic",
+ None,
+ "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>,
- range: Range<'_>,
+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 {