1 use clippy_utils::consts::constant_simple;
2 use clippy_utils::diagnostics::span_lint_and_sugg;
3 use clippy_utils::source::{indent_of, reindent_multiline, snippet_opt};
4 use clippy_utils::ty::is_type_diagnostic_item;
5 use clippy_utils::usage::contains_return_break_continue_macro;
6 use clippy_utils::{is_res_lang_ctor, path_to_local_id, sugg};
7 use if_chain::if_chain;
8 use rustc_errors::Applicability;
9 use rustc_hir::def::{DefKind, Res};
10 use rustc_hir::LangItem::{OptionNone, ResultErr};
11 use rustc_hir::{Arm, Expr, PatKind};
12 use rustc_lint::LateContext;
13 use rustc_middle::ty::DefIdTree;
16 use super::MANUAL_UNWRAP_OR;
18 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>, scrutinee: &'tcx Expr<'_>, arms: &'tcx [Arm<'_>]) {
19 let ty = cx.typeck_results().expr_ty(scrutinee);
21 if let Some(ty_name) = if is_type_diagnostic_item(cx, ty, sym::Option) {
23 } else if is_type_diagnostic_item(cx, ty, sym::Result) {
28 if let Some(or_arm) = applicable_or_arm(cx, arms);
29 if let Some(or_body_snippet) = snippet_opt(cx, or_arm.body.span);
30 if let Some(indent) = indent_of(cx, expr.span);
31 if constant_simple(cx, cx.typeck_results(), or_arm.body).is_some();
33 let reindented_or_body =
34 reindent_multiline(or_body_snippet.into(), true, Some(indent));
36 let suggestion = if scrutinee.span.from_expansion() {
37 // we don't want parentheses around macro, e.g. `(some_macro!()).unwrap_or(0)`
38 sugg::Sugg::hir_with_macro_callsite(cx, scrutinee, "..")
41 sugg::Sugg::hir(cx, scrutinee, "..").maybe_par()
46 MANUAL_UNWRAP_OR, expr.span,
47 &format!("this pattern reimplements `{ty_name}::unwrap_or`"),
50 "{suggestion}.unwrap_or({reindented_or_body})",
52 Applicability::MachineApplicable,
58 fn applicable_or_arm<'a>(cx: &LateContext<'_>, arms: &'a [Arm<'a>]) -> Option<&'a Arm<'a>> {
61 if arms.iter().all(|arm| arm.guard.is_none());
62 if let Some((idx, or_arm)) = arms.iter().enumerate().find(|(_, arm)| {
64 PatKind::Path(ref qpath) => is_res_lang_ctor(cx, cx.qpath_res(qpath, arm.pat.hir_id), OptionNone),
65 PatKind::TupleStruct(ref qpath, [pat], _) =>
66 matches!(pat.kind, PatKind::Wild)
67 && is_res_lang_ctor(cx, cx.qpath_res(qpath, arm.pat.hir_id), ResultErr),
71 let unwrap_arm = &arms[1 - idx];
72 if let PatKind::TupleStruct(ref qpath, [unwrap_pat], _) = unwrap_arm.pat.kind;
73 if let Res::Def(DefKind::Ctor(..), ctor_id) = cx.qpath_res(qpath, unwrap_arm.pat.hir_id);
74 if let Some(variant_id) = cx.tcx.opt_parent(ctor_id);
75 if cx.tcx.lang_items().option_some_variant() == Some(variant_id)
76 || cx.tcx.lang_items().result_ok_variant() == Some(variant_id);
77 if let PatKind::Binding(_, binding_hir_id, ..) = unwrap_pat.kind;
78 if path_to_local_id(unwrap_arm.body, binding_hir_id);
79 if cx.typeck_results().expr_adjustments(unwrap_arm.body).is_empty();
80 if !contains_return_break_continue_macro(or_arm.body);