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

   1 use clippy_utils::diagnostics::span_lint_and_help;
   2 use clippy_utils::is_in_test_function;
   3 use clippy_utils::ty::is_type_diagnostic_item;
   4 use rustc_hir as hir;
   5 use rustc_lint::LateContext;
   6 use rustc_span::sym;
   7
   8 use super::UNWRAP_USED;
   9
  10 /// lint use of `unwrap()` for `Option`s and `Result`s
  11 pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, allow_unwrap_in_tests: bool) {
  12     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
  13
  14     let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) {
  15         Some((UNWRAP_USED, "an Option", "None"))
  16     } else if is_type_diagnostic_item(cx, obj_ty, sym::Result) {
  17         Some((UNWRAP_USED, "a Result", "Err"))
  18     } else {
  19         None
  20     };
  21
  22     if allow_unwrap_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
  23         return;
  24     }
  25
  26     if let Some((lint, kind, none_value)) = mess {
  27         span_lint_and_help(
  28             cx,
  29             lint,
  30             expr.span,
  31             &format!("used `unwrap()` on `{}` value", kind,),
  32             None,
  33             &format!(
  34                 "if you don't want to handle the `{}` case gracefully, consider \
  35                 using `expect()` to provide a better panic message",
  36                 none_value,
  37             ),
  38         );
  39     }
  40 }