src/tools/clippy/clippy_lints/src/casts/as_ptr_cast_mut.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::source::snippet_opt;
   3 use rustc_errors::Applicability;
   4 use rustc_hir::{Expr, ExprKind};
   5 use rustc_lint::LateContext;
   6 use rustc_middle::{
   7     mir::Mutability,
   8     ty::{self, Ty, TypeAndMut},
   9 };
  10
  11 use super::AS_PTR_CAST_MUT;
  12
  13 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>, cast_to: Ty<'_>) {
  14     if let ty::RawPtr(ptrty @ TypeAndMut { mutbl: Mutability::Mut, .. }) = cast_to.kind()
  15         && let ty::RawPtr(TypeAndMut { mutbl: Mutability::Not, .. }) =
  16             cx.typeck_results().node_type(cast_expr.hir_id).kind()
  17         && let ExprKind::MethodCall(method_name, receiver, [], _) = cast_expr.peel_blocks().kind
  18         && method_name.ident.name == rustc_span::sym::as_ptr
  19         && let Some(as_ptr_did) = cx.typeck_results().type_dependent_def_id(cast_expr.peel_blocks().hir_id)
  20         && let as_ptr_sig = cx.tcx.fn_sig(as_ptr_did)
  21         && let Some(first_param_ty) = as_ptr_sig.skip_binder().inputs().iter().next()
  22         && let ty::Ref(_, _, Mutability::Not) = first_param_ty.kind()
  23         && let Some(recv) = snippet_opt(cx, receiver.span)
  24     {
  25         // `as_mut_ptr` might not exist
  26         let applicability = Applicability::MaybeIncorrect;
  27
  28         span_lint_and_sugg(
  29             cx,
  30             AS_PTR_CAST_MUT,
  31             expr.span,
  32             &format!("casting the result of `as_ptr` to *{ptrty}"),
  33             "replace with",
  34             format!("{recv}.as_mut_ptr()"),
  35             applicability
  36         );
  37     }
  38 }