use crate::utils;
use crate::utils::higher;
use crate::utils::higher::Range;
-use crate::rustc::hir::*;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::rustc::ty;
-use crate::syntax::ast::RangeLimits;
+use rustc::ty;
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use syntax::ast::RangeLimits;
-/// **What it does:** Checks for out of bounds array indexing with a constant
-/// index.
-///
-/// **Why is this bad?** This will always panic at runtime.
-///
-/// **Known problems:** Hopefully none.
-///
-/// **Example:**
-/// ```rust
-/// let x = [1,2,3,4];
-///
-/// // Bad
-/// x[9];
-/// &x[2..9];
-///
-/// // Good
-/// x[0];
-/// x[3];
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for out of bounds array indexing with a constant
+ /// index.
+ ///
+ /// **Why is this bad?** This will always panic at runtime.
+ ///
+ /// **Known problems:** Hopefully none.
+ ///
+ /// **Example:**
+ /// ```no_run
+ /// # #![allow(const_err)]
+ /// let x = [1, 2, 3, 4];
+ ///
+ /// // Bad
+ /// x[9];
+ /// &x[2..9];
+ ///
+ /// // Good
+ /// x[0];
+ /// x[3];
+ /// ```
pub OUT_OF_BOUNDS_INDEXING,
correctness,
"out of bounds constant indexing"
}
-/// **What it does:** Checks for usage of indexing or slicing. Arrays are special cased, 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
-/// safe alternatives.
-///
-/// **Known problems:** Hopefully none.
-///
-/// **Example:**
-/// ```rust
-/// // Vector
-/// let x = vec![0; 5];
-///
-/// // Bad
-/// x[2];
-/// &x[2..100];
-/// &x[2..];
-/// &x[..100];
-///
-/// // Good
-/// x.get(2);
-/// x.get(2..100);
-/// x.get(2..);
-/// x.get(..100);
-///
-/// // Array
-/// let y = [0, 1, 2, 3];
-///
-/// // Bad
-/// &y[10..100];
-/// &y[10..];
-/// &y[..100];
-///
-/// // Good
-/// &y[2..];
-/// &y[..2];
-/// &y[0..3];
-/// y.get(10);
-/// y.get(10..100);
-/// y.get(10..);
-/// y.get(..100);
-/// ```
declare_clippy_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
+ /// safe alternatives.
+ ///
+ /// **Known problems:** Hopefully none.
+ ///
+ /// **Example:**
+ /// ```rust,no_run
+ /// // Vector
+ /// let x = vec![0; 5];
+ ///
+ /// // Bad
+ /// x[2];
+ /// &x[2..100];
+ /// &x[2..];
+ /// &x[..100];
+ ///
+ /// // Good
+ /// x.get(2);
+ /// x.get(2..100);
+ /// x.get(2..);
+ /// x.get(..100);
+ ///
+ /// // Array
+ /// let y = [0, 1, 2, 3];
+ ///
+ /// // Bad
+ /// &y[10..100];
+ /// &y[10..];
+ /// &y[..100];
+ ///
+ /// // Good
+ /// &y[2..];
+ /// &y[..2];
+ /// &y[0..3];
+ /// y.get(10);
+ /// y.get(10..100);
+ /// y.get(10..);
+ /// y.get(..100);
+ /// ```
pub INDEXING_SLICING,
restriction,
"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)
- }
-}
+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.node {
+ 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) {
- // 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();
- // Index is a constant range.
- if let Some((start, end)) = to_const_range(cx, range, size) {
- if start > size || end > size {
+ // Ranged indexes, i.e., &x[n..m], &x[n..], &x[..n] and &x[..]
+ if let ty::Array(_, s) = ty.kind {
+ let size: u128 = s.eval_usize(cx.tcx, cx.param_env).into();
+
+ let const_range = to_const_range(cx, range, size);
+
+ if let (Some(start), _) = const_range {
+ if start > size {
utils::span_lint(
cx,
OUT_OF_BOUNDS_INDEXING,
- expr.span,
+ range.start.map_or(expr.span, |start| start.span),
"range is out of bounds",
);
+ return;
}
+ }
+
+ if let (_, Some(end)) = const_range {
+ if end > size {
+ utils::span_lint(
+ cx,
+ OUT_OF_BOUNDS_INDEXING,
+ range.end.map_or(expr.span, |end| end.span),
+ "range is out of bounds",
+ );
+ return;
+ }
+ }
+
+ if let (Some(_), Some(_)) = const_range {
+ // early return because both start and end are constants
+ // and we have proven above that they are in bounds
return;
}
}
(None, None) => return, // [..] is ok.
};
- utils::span_help_and_lint(
- cx,
- INDEXING_SLICING,
- expr.span,
- "slicing may panic.",
- help_msg,
- );
+ utils::span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic.", 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) {
// Let rustc's `const_err` lint handle constant `usize` indexing on arrays.
}
}
- utils::span_help_and_lint(
+ utils::span_lint_and_help(
cx,
INDEXING_SLICING,
expr.span,
}
}
-/// Returns an option containing a tuple with the start and end (exclusive) of
-/// the range.
+/// 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<'_>,
array_size: u128,
-) -> Option<(u128, u128)> {
- let s = range
- .start
- .map(|expr| constant(cx, cx.tables, expr).map(|(c, _)| c));
+) -> (Option<u128>, Option<u128>) {
+ let s = range.start.map(|expr| constant(cx, cx.tables, expr).map(|(c, _)| c));
let start = match s {
- Some(Some(Constant::Int(x))) => x,
- Some(_) => return None,
- None => 0,
+ 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.tables, expr).map(|(c, _)| c));
let end = match e {
- Some(Some(Constant::Int(x))) => if range.limits == RangeLimits::Closed {
- x + 1
- } else {
- x
+ Some(Some(Constant::Int(x))) => {
+ if range.limits == RangeLimits::Closed {
+ Some(x + 1)
+ } else {
+ Some(x)
+ }
},
- Some(_) => return None,
- None => array_size,
+ Some(_) => None,
+ None => Some(array_size),
};
- Some((start, end))
+ (start, end)
}
projects / rust.git / blobdiff