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

   1 use clippy_utils::diagnostics::span_lint_and_then;
   2 use rustc_errors::Applicability;
   3 use rustc_hir::{Expr, Ty, TyKind};
   4 use rustc_lint::LateContext;
   5 use rustc_middle::ty;
   6
   7 use super::AS_UNDERSCORE;
   8
   9 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ty: &'tcx Ty<'_>) {
  10     if matches!(ty.kind, TyKind::Infer) {
  11         span_lint_and_then(cx, AS_UNDERSCORE, expr.span, "using `as _` conversion", |diag| {
  12             let ty_resolved = cx.typeck_results().expr_ty(expr);
  13             if let ty::Error(_) = ty_resolved.kind() {
  14                 diag.help("consider giving the type explicitly");
  15             } else {
  16                 diag.span_suggestion(
  17                     ty.span,
  18                     "consider giving the type explicitly",
  19                     ty_resolved,
  20                     Applicability::MachineApplicable,
  21                 );
  22             }
  23         });
  24     }
  25 }