src/tools/clippy/clippy_lints/src/methods/uninit_assumed_init.rs

   1 use crate::utils::{match_def_path, match_qpath, paths, span_lint};
   2 use if_chain::if_chain;
   3 use rustc_hir as hir;
   4 use rustc_lint::LateContext;
   5 use rustc_middle::ty::{self, Ty};
   6
   7 use super::UNINIT_ASSUMED_INIT;
   8
   9 /// lint for `MaybeUninit::uninit().assume_init()` (we already have the latter)
  10 pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, outer: &hir::Expr<'_>) {
  11     if_chain! {
  12         if let hir::ExprKind::Call(ref callee, ref args) = expr.kind;
  13         if args.is_empty();
  14         if let hir::ExprKind::Path(ref path) = callee.kind;
  15         if match_qpath(path, &paths::MEM_MAYBEUNINIT_UNINIT);
  16         if !is_maybe_uninit_ty_valid(cx, cx.typeck_results().expr_ty_adjusted(outer));
  17         then {
  18             span_lint(
  19                 cx,
  20                 UNINIT_ASSUMED_INIT,
  21                 outer.span,
  22                 "this call for this type may be undefined behavior"
  23             );
  24         }
  25     }
  26 }
  27
  28 fn is_maybe_uninit_ty_valid(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
  29     match ty.kind() {
  30         ty::Array(ref component, _) => is_maybe_uninit_ty_valid(cx, component),
  31         ty::Tuple(ref types) => types.types().all(|ty| is_maybe_uninit_ty_valid(cx, ty)),
  32         ty::Adt(ref adt, _) => match_def_path(cx, adt.did, &paths::MEM_MAYBEUNINIT),
  33         _ => false,
  34     }
  35 }