src/tools/clippy/clippy_lints/src/transmute/transmute_int_to_bool.rs

   1 use super::TRANSMUTE_INT_TO_BOOL;
   2 use clippy_utils::diagnostics::span_lint_and_then;
   3 use clippy_utils::sugg;
   4 use rustc_ast as ast;
   5 use rustc_errors::Applicability;
   6 use rustc_hir::Expr;
   7 use rustc_lint::LateContext;
   8 use rustc_middle::ty::{self, Ty};
   9 use std::borrow::Cow;
  10
  11 /// Checks for `transmute_int_to_bool` lint.
  12 /// Returns `true` if it's triggered, otherwise returns `false`.
  13 pub(super) fn check<'tcx>(
  14     cx: &LateContext<'tcx>,
  15     e: &'tcx Expr<'_>,
  16     from_ty: Ty<'tcx>,
  17     to_ty: Ty<'tcx>,
  18     args: &'tcx [Expr<'_>],
  19 ) -> bool {
  20     match (&from_ty.kind(), &to_ty.kind()) {
  21         (ty::Int(ty::IntTy::I8) | ty::Uint(ty::UintTy::U8), ty::Bool) => {
  22             span_lint_and_then(
  23                 cx,
  24                 TRANSMUTE_INT_TO_BOOL,
  25                 e.span,
  26                 &format!("transmute from a `{}` to a `bool`", from_ty),
  27                 |diag| {
  28                     let arg = sugg::Sugg::hir(cx, &args[0], "..");
  29                     let zero = sugg::Sugg::NonParen(Cow::from("0"));
  30                     diag.span_suggestion(
  31                         e.span,
  32                         "consider using",
  33                         sugg::make_binop(ast::BinOpKind::Ne, &arg, &zero).to_string(),
  34                         Applicability::Unspecified,
  35                     );
  36                 },
  37             );
  38             true
  39         },
  40         _ => false,
  41     }
  42 }