1 use clippy_utils::diagnostics::span_lint_and_sugg;
2 use clippy_utils::is_slice_of_primitives;
3 use clippy_utils::source::snippet_with_applicability;
4 use if_chain::if_chain;
5 use rustc_ast::LitKind;
6 use rustc_errors::Applicability;
8 use rustc_lint::LateContext;
9 use rustc_span::source_map::Spanned;
13 pub(super) fn check<'tcx>(
14 cx: &LateContext<'tcx>,
15 expr: &'tcx hir::Expr<'_>,
16 recv: &'tcx hir::Expr<'_>,
17 arg: &'tcx hir::Expr<'_>,
20 if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
21 if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
22 if cx.tcx.type_of(impl_id).is_slice();
23 if let Some(_) = is_slice_of_primitives(cx, recv);
24 if let hir::ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = arg.kind;
26 let mut app = Applicability::MachineApplicable;
27 let slice_name = snippet_with_applicability(cx, recv.span, "..", &mut app);
32 &format!("accessing first element with `{slice_name}.get(0)`"),
34 format!("{slice_name}.first()"),