clippy_lints/src/casts/cast_abs_to_unsigned.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::sugg::Sugg;
   3 use clippy_utils::{meets_msrv, msrvs};
   4 use if_chain::if_chain;
   5 use rustc_errors::Applicability;
   6 use rustc_hir::{Expr, ExprKind};
   7 use rustc_lint::LateContext;
   8 use rustc_middle::ty::Ty;
   9 use rustc_semver::RustcVersion;
  10
  11 use super::CAST_ABS_TO_UNSIGNED;
  12
  13 pub(super) fn check(
  14     cx: &LateContext<'_>,
  15     expr: &Expr<'_>,
  16     cast_expr: &Expr<'_>,
  17     cast_from: Ty<'_>,
  18     cast_to: Ty<'_>,
  19     msrv: Option<RustcVersion>,
  20 ) {
  21     if_chain! {
  22         if meets_msrv(msrv, msrvs::UNSIGNED_ABS);
  23         if cast_from.is_integral();
  24         if cast_to.is_integral();
  25         if cast_from.is_signed();
  26         if !cast_to.is_signed();
  27         if let ExprKind::MethodCall(method_path, args, _) = cast_expr.kind;
  28         if let method_name = method_path.ident.name.as_str();
  29         if method_name == "abs";
  30         then {
  31             span_lint_and_sugg(
  32                 cx,
  33                 CAST_ABS_TO_UNSIGNED,
  34                 expr.span,
  35                 &format!("casting the result of `{}::{}()` to {}", cast_from, method_name, cast_to),
  36                 "replace with",
  37                 format!("{}.unsigned_abs()", Sugg::hir(cx, &args[0], "..")),
  38                 Applicability::MachineApplicable,
  39             );
  40         }
  41     }
  42 }