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J-ZhengLiJ-ZhengLi
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reduce code repetition for the original lint
1 parent fb94992 commit 2c98b63

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2 files changed

+59
-73
lines changed

2 files changed

+59
-73
lines changed

‎clippy_lints/src/question_mark.rs

Lines changed: 55 additions & 69 deletions
Original file line numberDiff line numberDiff line change
@@ -1,16 +1,16 @@
11
use clippy_utils::diagnostics::span_lint_and_sugg;
22
use clippy_utils::higher;
33
use clippy_utils::source::snippet_with_applicability;
4-
use clippy_utils::sugg::Sugg;
54
use clippy_utils::ty::is_type_diagnostic_item;
65
use clippy_utils::{eq_expr_value, is_lang_ctor, path_to_local, path_to_local_id, peel_blocks, peel_blocks_with_stmt};
76
use if_chain::if_chain;
87
use rustc_errors::Applicability;
98
use rustc_hir::LangItem::{OptionNone, OptionSome, ResultOk};
109
use rustc_hir::{BindingAnnotation, Expr, ExprKind, PatKind};
1110
use rustc_lint::{LateContext, LateLintPass};
11+
use rustc_middle::ty::Ty;
1212
use rustc_session::{declare_lint_pass, declare_tool_lint};
13-
use rustc_span::sym;
13+
use rustc_span::{sym, symbol::Symbol};
1414

1515
declare_clippy_lint! {
1616
/// ### What it does
@@ -60,35 +60,25 @@ impl QuestionMark {
6060
if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr);
6161
if let ExprKind::MethodCall(segment, args, _) = &cond.kind;
6262
if let Some(subject) = args.get(0);
63-
if (Self::option_check_and_early_return(cx, subject, then) && segment.ident.name == sym!(is_none)) ||
64-
(Self::result_check_and_early_return(cx, subject, then) && segment.ident.name == sym!(is_err));
63+
let subject_ty = cx.typeck_results().expr_ty(subject);
64+
if (Self::check_early_return(cx, subject, then, subject_ty, sym::Option) &&
65+
segment.ident.name == sym!(is_none)) ||
66+
(Self::check_early_return(cx, subject, then, subject_ty, sym::Result) &&
67+
segment.ident.name == sym!(is_err));
6568
then {
6669
let mut applicability = Applicability::MachineApplicable;
67-
let receiver_str = &Sugg::hir_with_applicability(cx, subject, "..", &mut applicability);
68-
let mut replacement: Option<String> = None;
70+
let receiver_str = snippet_with_applicability(cx, subject.span, "..", &mut applicability);
71+
let by_ref = !subject_ty.is_copy_modulo_regions(cx.tcx.at(subject.span), cx.param_env) &&
72+
!matches!(subject.kind, ExprKind::Call(..) | ExprKind::MethodCall(..));
73+
let mut suggestion = String::new();
6974
if let Some(else_inner) = r#else {
7075
if eq_expr_value(cx, subject, peel_blocks(else_inner)) {
71-
replacement = Some(format!("Some({}?)", receiver_str));
76+
suggestion = format!("Some({}?)", receiver_str);
7277
}
73-
} else if Self::moves_by_default(cx, subject)
74-
&& !matches!(subject.kind, ExprKind::Call(..) | ExprKind::MethodCall(..))
75-
{
76-
replacement = Some(format!("{}.as_ref()?;", receiver_str));
7778
} else {
78-
replacement = Some(format!("{}?;", receiver_str));
79-
}
80-
81-
if let Some(replacement_str) = replacement {
82-
span_lint_and_sugg(
83-
cx,
84-
QUESTION_MARK,
85-
expr.span,
86-
"this block may be rewritten with the `?` operator",
87-
"replace it with",
88-
replacement_str,
89-
applicability,
90-
);
79+
suggestion = format!("{}{}?;", receiver_str, if by_ref { ".as_ref()" } else { "" });
9180
}
81+
Self::offer_suggestion(cx, expr, suggestion, applicability);
9282
}
9383
}
9484
}
@@ -98,8 +88,11 @@ impl QuestionMark {
9888
if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: Some(if_else) })
9989
= higher::IfLet::hir(cx, expr);
10090
if let PatKind::TupleStruct(ref path1, fields, None) = let_pat.kind;
101-
if (Self::option_check_and_early_return(cx, let_expr, if_else) && is_lang_ctor(cx, path1, OptionSome)) ||
102-
(Self::result_check_and_early_return(cx, let_expr, if_else) && is_lang_ctor(cx, path1, ResultOk));
91+
let let_expr_ty = cx.typeck_results().expr_ty(let_expr);
92+
if (Self::check_early_return(cx, let_expr, if_else, let_expr_ty, sym::Option) &&
93+
is_lang_ctor(cx, path1, OptionSome)) ||
94+
(Self::check_early_return(cx, let_expr, if_else, let_expr_ty, sym::Result) &&
95+
is_lang_ctor(cx, path1, ResultOk));
10396

10497
if let PatKind::Binding(annot, bind_id, _, _) = fields[0].kind;
10598
let by_ref = matches!(annot, BindingAnnotation::Ref | BindingAnnotation::RefMut);
@@ -108,59 +101,52 @@ impl QuestionMark {
108101
let mut applicability = Applicability::MachineApplicable;
109102
let receiver_str = snippet_with_applicability(cx, let_expr.span, "..", &mut applicability);
110103
let replacement = format!("{}{}?", receiver_str, if by_ref { ".as_ref()" } else { "" },);
111-
112-
span_lint_and_sugg(
113-
cx,
114-
QUESTION_MARK,
115-
expr.span,
116-
"this if-let-else may be rewritten with the `?` operator",
117-
"replace it with",
118-
replacement,
119-
applicability,
120-
);
104+
Self::offer_suggestion(cx, expr, replacement, applicability);
121105
}
122106
}
123107
}
124108

125-
fn result_check_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>, nested_expr: &Expr<'_>) -> bool {
126-
Self::is_result(cx, expr) && Self::expression_returns_unmodified_err(cx, nested_expr, expr)
127-
}
128-
129-
fn option_check_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>, nested_expr: &Expr<'_>) -> bool {
130-
Self::is_option(cx, expr) && Self::expression_returns_none(cx, nested_expr)
131-
}
132-
133-
fn moves_by_default(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
134-
let expr_ty = cx.typeck_results().expr_ty(expression);
135-
136-
!expr_ty.is_copy_modulo_regions(cx.tcx.at(expression.span), cx.param_env)
109+
fn check_early_return(
110+
cx: &LateContext<'_>,
111+
cond_expr: &Expr<'_>,
112+
nested_expr: &Expr<'_>,
113+
cond_ty: Ty<'_>,
114+
ret_sym: Symbol,
115+
) -> bool {
116+
is_type_diagnostic_item(cx, cond_ty, ret_sym)
117+
&& Self::expr_return_none_or_err(cx, cond_expr, nested_expr, ret_sym)
137118
}
138119

139-
fn is_option(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
140-
let expr_ty = cx.typeck_results().expr_ty(expression);
141-
142-
is_type_diagnostic_item(cx, expr_ty, sym::Option)
143-
}
144-
145-
fn is_result(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
146-
let expr_ty = cx.typeck_results().expr_ty(expression);
147-
148-
is_type_diagnostic_item(cx, expr_ty, sym::Result)
149-
}
150-
151-
fn expression_returns_none(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool {
152-
match peel_blocks_with_stmt(expression).kind {
153-
ExprKind::Ret(Some(expr)) => Self::expression_returns_none(cx, expr),
154-
ExprKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
120+
fn expr_return_none_or_err(
121+
cx: &LateContext<'_>,
122+
cond_expr: &Expr<'_>,
123+
nested_expr: &Expr<'_>,
124+
ret_sym: Symbol,
125+
) -> bool {
126+
match peel_blocks_with_stmt(nested_expr).kind {
127+
ExprKind::Ret(Some(ret_expr)) => Self::expr_return_none_or_err(cx, cond_expr, ret_expr, ret_sym),
128+
ExprKind::Path(ref qpath) => match ret_sym {
129+
sym::Option => is_lang_ctor(cx, qpath, OptionNone),
130+
sym::Result => {
131+
path_to_local(nested_expr).is_some() && path_to_local(nested_expr) == path_to_local(cond_expr)
132+
},
133+
_ => false,
134+
},
155135
_ => false,
156136
}
157137
}
158138

159-
fn expression_returns_unmodified_err(cx: &LateContext<'_>, expr: &Expr<'_>, cond_expr: &Expr<'_>) -> bool {
160-
match peel_blocks_with_stmt(expr).kind {
161-
ExprKind::Ret(Some(ret_expr)) => Self::expression_returns_unmodified_err(cx, ret_expr, cond_expr),
162-
ExprKind::Path(_) => path_to_local(expr).is_some() && path_to_local(expr) == path_to_local(cond_expr),
163-
_ => false,
139+
fn offer_suggestion(cx: &LateContext<'_>, expr: &Expr<'_>, suggestion: String, applicability: Applicability) {
140+
if !suggestion.is_empty() {
141+
span_lint_and_sugg(
142+
cx,
143+
QUESTION_MARK,
144+
expr.span,
145+
"this block may be rewritten with the `?` operator",
146+
"replace it with",
147+
suggestion,
148+
applicability,
149+
);
164150
}
165151
}
166152
}

‎tests/ui/question_mark.stderr

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -35,7 +35,7 @@ LL | | self.opt
3535
LL | | };
3636
| |_________^ help: replace it with: `Some(self.opt?)`
3737

38-
error: this if-let-else may be rewritten with the `?` operator
38+
error: this block may be rewritten with the `?` operator
3939
--> $DIR/question_mark.rs:65:17
4040
|
4141
LL | let _ = if let Some(x) = self.opt {
@@ -70,7 +70,7 @@ LL | | return None;
7070
LL | | }
7171
| |_________^ help: replace it with: `self.opt.as_ref()?;`
7272

73-
error: this if-let-else may be rewritten with the `?` operator
73+
error: this block may be rewritten with the `?` operator
7474
--> $DIR/question_mark.rs:105:26
7575
|
7676
LL | let v: &Vec<_> = if let Some(ref v) = self.opt {
@@ -81,7 +81,7 @@ LL | | return None;
8181
LL | | };
8282
| |_________^ help: replace it with: `self.opt.as_ref()?`
8383

84-
error: this if-let-else may be rewritten with the `?` operator
84+
error: this block may be rewritten with the `?` operator
8585
--> $DIR/question_mark.rs:115:17
8686
|
8787
LL | let v = if let Some(v) = self.opt {
@@ -100,7 +100,7 @@ LL | | return None;
100100
LL | | }
101101
| |_____^ help: replace it with: `f()?;`
102102

103-
error: this if-let-else may be rewritten with the `?` operator
103+
error: this block may be rewritten with the `?` operator
104104
--> $DIR/question_mark.rs:142:13
105105
|
106106
LL | let _ = if let Ok(x) = x { x } else { return x };

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