1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::macros::root_macro_call_first_node;
use clippy_utils::return_ty;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::visitors::{for_each_expr, Descend};
use core::ops::ControlFlow;
use rustc_hir as hir;
use rustc_hir::intravisit::FnKind;
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::{sym, Span};
declare_clippy_lint! {
/// ### What it does
/// Checks for usage of `panic!`, `unimplemented!`, `todo!`, `unreachable!` or assertions in a function of type result.
///
/// ### Why is this bad?
/// For some codebases, it is desirable for functions of type result to return an error instead of crashing. Hence panicking macros should be avoided.
///
/// ### Known problems
/// Functions called from a function returning a `Result` may invoke a panicking macro. This is not checked.
///
/// ### Example
/// ```rust
/// fn result_with_panic() -> Result<bool, String>
/// {
/// panic!("error");
/// }
/// ```
/// Use instead:
/// ```rust
/// fn result_without_panic() -> Result<bool, String> {
/// Err(String::from("error"))
/// }
/// ```
#[clippy::version = "1.48.0"]
pub PANIC_IN_RESULT_FN,
restriction,
"functions of type `Result<..>` that contain `panic!()`, `todo!()`, `unreachable()`, `unimplemented()` or assertion"
}
declare_lint_pass!(PanicInResultFn => [PANIC_IN_RESULT_FN]);
impl<'tcx> LateLintPass<'tcx> for PanicInResultFn {
fn check_fn(
&mut self,
cx: &LateContext<'tcx>,
fn_kind: FnKind<'tcx>,
_: &'tcx hir::FnDecl<'tcx>,
body: &'tcx hir::Body<'tcx>,
span: Span,
hir_id: hir::HirId,
) {
if !matches!(fn_kind, FnKind::Closure) && is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym::Result) {
lint_impl_body(cx, span, body);
}
}
}
fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir::Body<'tcx>) {
let mut panics = Vec::new();
let _: Option<!> = for_each_expr(body.value, |e| {
let Some(macro_call) = root_macro_call_first_node(cx, e) else {
return ControlFlow::Continue(Descend::Yes);
};
if matches!(
cx.tcx.item_name(macro_call.def_id).as_str(),
"unimplemented" | "unreachable" | "panic" | "todo" | "assert" | "assert_eq" | "assert_ne"
) {
panics.push(macro_call.span);
ControlFlow::Continue(Descend::No)
} else {
ControlFlow::Continue(Descend::Yes)
}
});
if !panics.is_empty() {
span_lint_and_then(
cx,
PANIC_IN_RESULT_FN,
impl_span,
"used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`",
move |diag| {
diag.help(
"`unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing",
);
diag.span_note(panics, "return Err() instead of panicking");
},
);
}
}
|
