//! lint on indexing and slicing operations
use clippy_utils::consts::{constant, Constant};
-use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
use clippy_utils::higher;
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};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
declare_clippy_lint! {
/// ### What it does
"indexing/slicing usage"
}
-declare_lint_pass!(IndexingSlicing => [INDEXING_SLICING, OUT_OF_BOUNDS_INDEXING]);
+impl_lint_pass!(IndexingSlicing => [INDEXING_SLICING, OUT_OF_BOUNDS_INDEXING]);
+
+#[derive(Copy, Clone)]
+pub struct IndexingSlicing {
+ suppress_restriction_lint_in_const: bool,
+}
+
+impl IndexingSlicing {
+ pub fn new(suppress_restriction_lint_in_const: bool) -> Self {
+ Self {
+ suppress_restriction_lint_in_const,
+ }
+ }
+}
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) {
+ if self.suppress_restriction_lint_in_const && cx.tcx.hir().is_inside_const_context(expr.hir_id) {
return;
}
if let ExprKind::Index(array, index) = &expr.kind {
+ let note = "the suggestion might not be applicable in constant blocks";
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[..]
(None, None) => return, // [..] is ok.
};
- span_lint_and_help(cx, INDEXING_SLICING, expr.span, "slicing may panic", None, help_msg);
+ span_lint_and_then(cx, INDEXING_SLICING, expr.span, "slicing may panic", |diag| {
+ diag.help(help_msg);
+
+ if cx.tcx.hir().is_inside_const_context(expr.hir_id) {
+ diag.note(note);
+ }
+ });
} else {
// Catchall non-range index, i.e., [n] or [n << m]
if let ty::Array(..) = ty.kind() {
}
}
- span_lint_and_help(
- cx,
- INDEXING_SLICING,
- expr.span,
- "indexing may panic",
- None,
- "consider using `.get(n)` or `.get_mut(n)` instead",
- );
+ span_lint_and_then(cx, INDEXING_SLICING, expr.span, "indexing may panic", |diag| {
+ diag.help("consider using `.get(n)` or `.get_mut(n)` instead");
+
+ if cx.tcx.hir().is_inside_const_context(expr.hir_id) {
+ diag.note(note);
+ }
+ });
}
}
}