1 files changed, 41 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/option_map_or_err_ok.rs b/src/tools/clippy/clippy_lints/src/methods/option_map_or_err_ok.rs
new file mode 100644
index 000000000..91e39d5a1
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/option_map_or_err_ok.rs
@@ -0,0 +1,41 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{is_res_lang_ctor, path_res};
+use rustc_errors::Applicability;
+use rustc_hir::LangItem::{ResultErr, ResultOk};
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_span::symbol::sym;
+
+use super::OPTION_MAP_OR_ERR_OK;
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'tcx>,
+    recv: &'tcx Expr<'_>,
+    or_expr: &'tcx Expr<'_>,
+    map_expr: &'tcx Expr<'_>,
+) {
+    // We check that it's called on an `Option` type.
+    if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(recv), sym::Option)
+        // We check that first we pass an `Err`.
+        && let ExprKind::Call(call, &[arg]) = or_expr.kind
+        && is_res_lang_ctor(cx, path_res(cx, call), ResultErr)
+        // And finally we check that it is mapped as `Ok`.
+        && is_res_lang_ctor(cx, path_res(cx, map_expr), ResultOk)
+    {
+        let msg = "called `map_or(Err(_), Ok)` on an `Option` value";
+        let self_snippet = snippet(cx, recv.span, "..");
+        let err_snippet = snippet(cx, arg.span, "..");
+        span_lint_and_sugg(
+            cx,
+            OPTION_MAP_OR_ERR_OK,
+            expr.span,
+            msg,
+            "try using `ok_or` instead",
+            format!("{self_snippet}.ok_or({err_snippet})"),
+            Applicability::MachineApplicable,
+        );
+    }
+}