clippy_lints/src/transmute/transmutes_expressible_as_ptr_casts.rs

   1 use super::utils::can_be_expressed_as_pointer_cast;
   2 use super::TRANSMUTES_EXPRESSIBLE_AS_PTR_CASTS;
   3 use clippy_utils::diagnostics::span_lint_and_then;
   4 use clippy_utils::sugg;
   5 use rustc_errors::Applicability;
   6 use rustc_hir::Expr;
   7 use rustc_lint::LateContext;
   8 use rustc_middle::ty::Ty;
   9
  10 /// Checks for `transmutes_expressible_as_ptr_casts` lint.
  11 /// Returns `true` if it's triggered, otherwise returns `false`.
  12 pub(super) fn check<'tcx>(
  13     cx: &LateContext<'tcx>,
  14     e: &'tcx Expr<'_>,
  15     from_ty: Ty<'tcx>,
  16     to_ty: Ty<'tcx>,
  17     args: &'tcx [Expr<'_>],
  18 ) -> bool {
  19     if can_be_expressed_as_pointer_cast(cx, e, from_ty, to_ty) {
  20         span_lint_and_then(
  21             cx,
  22             TRANSMUTES_EXPRESSIBLE_AS_PTR_CASTS,
  23             e.span,
  24             &format!(
  25                 "transmute from `{}` to `{}` which could be expressed as a pointer cast instead",
  26                 from_ty, to_ty
  27             ),
  28             |diag| {
  29                 if let Some(arg) = sugg::Sugg::hir_opt(cx, &args[0]) {
  30                     let sugg = arg.as_ty(&to_ty.to_string()).to_string();
  31                     diag.span_suggestion(e.span, "try", sugg, Applicability::MachineApplicable);
  32                 }
  33             },
  34         );
  35         true
  36     } else {
  37         false
  38     }
  39 }