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Michael Wright
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Make approx_const MSRV aware
Fixes rust-lang#7623.
1 parent 265b8ec commit a23af89

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5 files changed

+81
-58
lines changed

5 files changed

+81
-58
lines changed

‎clippy_lints/src/approx_const.rs

Lines changed: 70 additions & 53 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,10 @@
11
use clippy_utils::diagnostics::span_lint;
2+
use clippy_utils::{meets_msrv, msrvs};
23
use rustc_ast::ast::{FloatTy, LitFloatType, LitKind};
34
use rustc_hir::{Expr, ExprKind};
4-
use rustc_lint::{LateContext, LateLintPass};
5-
use rustc_session::{declare_lint_pass, declare_tool_lint};
5+
use rustc_lint::{LateContext, LateLintPass, LintContext};
6+
use rustc_semver::RustcVersion;
7+
use rustc_session::{declare_tool_lint, impl_lint_pass};
68
use rustc_span::symbol;
79
use std::f64::consts as f64;
810

@@ -36,68 +38,83 @@ declare_clippy_lint! {
3638
"the approximate of a known float constant (in `std::fXX::consts`)"
3739
}
3840

39-
// Tuples are of the form (constant, name, min_digits)
40-
const KNOWN_CONSTS: [(f64, &str, usize); 18] = [
41-
(f64::E, "E", 4),
42-
(f64::FRAC_1_PI, "FRAC_1_PI", 4),
43-
(f64::FRAC_1_SQRT_2, "FRAC_1_SQRT_2", 5),
44-
(f64::FRAC_2_PI, "FRAC_2_PI", 5),
45-
(f64::FRAC_2_SQRT_PI, "FRAC_2_SQRT_PI", 5),
46-
(f64::FRAC_PI_2, "FRAC_PI_2", 5),
47-
(f64::FRAC_PI_3, "FRAC_PI_3", 5),
48-
(f64::FRAC_PI_4, "FRAC_PI_4", 5),
49-
(f64::FRAC_PI_6, "FRAC_PI_6", 5),
50-
(f64::FRAC_PI_8, "FRAC_PI_8", 5),
51-
(f64::LN_2, "LN_2", 5),
52-
(f64::LN_10, "LN_10", 5),
53-
(f64::LOG2_10, "LOG2_10", 5),
54-
(f64::LOG2_E, "LOG2_E", 5),
55-
(f64::LOG10_2, "LOG10_2", 5),
56-
(f64::LOG10_E, "LOG10_E", 5),
57-
(f64::PI, "PI", 3),
58-
(f64::SQRT_2, "SQRT_2", 5),
41+
// Tuples are of the form (constant, name, min_digits, msrv)
42+
const KNOWN_CONSTS: [(f64, &str, usize, Option<RustcVersion>); 18] = [
43+
(f64::E, "E", 4, None),
44+
(f64::FRAC_1_PI, "FRAC_1_PI", 4, None),
45+
(f64::FRAC_1_SQRT_2, "FRAC_1_SQRT_2", 5, None),
46+
(f64::FRAC_2_PI, "FRAC_2_PI", 5, None),
47+
(f64::FRAC_2_SQRT_PI, "FRAC_2_SQRT_PI", 5, None),
48+
(f64::FRAC_PI_2, "FRAC_PI_2", 5, None),
49+
(f64::FRAC_PI_3, "FRAC_PI_3", 5, None),
50+
(f64::FRAC_PI_4, "FRAC_PI_4", 5, None),
51+
(f64::FRAC_PI_6, "FRAC_PI_6", 5, None),
52+
(f64::FRAC_PI_8, "FRAC_PI_8", 5, None),
53+
(f64::LN_2, "LN_2", 5, None),
54+
(f64::LN_10, "LN_10", 5, None),
55+
(f64::LOG2_10, "LOG2_10", 5, Some(msrvs::LOG2_10)),
56+
(f64::LOG2_E, "LOG2_E", 5, None),
57+
(f64::LOG10_2, "LOG10_2", 5, Some(msrvs::LOG10_2)),
58+
(f64::LOG10_E, "LOG10_E", 5, None),
59+
(f64::PI, "PI", 3, None),
60+
(f64::SQRT_2, "SQRT_2", 5, None),
5961
];
6062

61-
declare_lint_pass!(ApproxConstant => [APPROX_CONSTANT]);
63+
pub struct ApproxConstant {
64+
msrv: Option<RustcVersion>,
65+
}
6266

63-
impl<'tcx> LateLintPass<'tcx> for ApproxConstant {
64-
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
65-
if let ExprKind::Lit(lit) = &e.kind {
66-
check_lit(cx, &lit.node, e);
67+
impl ApproxConstant {
68+
#[must_use]
69+
pub fn new(msrv: Option<RustcVersion>) -> Self {
70+
Self { msrv }
71+
}
72+
73+
fn check_lit(&self, cx: &LateContext<'_>, lit: &LitKind, e: &Expr<'_>) {
74+
match *lit {
75+
LitKind::Float(s, LitFloatType::Suffixed(fty)) => match fty {
76+
FloatTy::F32 => self.check_known_consts(cx, e, s, "f32"),
77+
FloatTy::F64 => self.check_known_consts(cx, e, s, "f64"),
78+
},
79+
LitKind::Float(s, LitFloatType::Unsuffixed) => self.check_known_consts(cx, e, s, "f{32, 64}"),
80+
_ => (),
6781
}
6882
}
69-
}
7083

71-
fn check_lit(cx: &LateContext<'_>, lit: &LitKind, e: &Expr<'_>) {
72-
match *lit {
73-
LitKind::Float(s, LitFloatType::Suffixed(fty)) => match fty {
74-
FloatTy::F32 => check_known_consts(cx, e, s, "f32"),
75-
FloatTy::F64 => check_known_consts(cx, e, s, "f64"),
76-
},
77-
LitKind::Float(s, LitFloatType::Unsuffixed) => check_known_consts(cx, e, s, "f{32, 64}"),
78-
_ => (),
84+
fn check_known_consts(&self, cx: &LateContext<'_>, e: &Expr<'_>, s: symbol::Symbol, module: &str) {
85+
let s = s.as_str();
86+
if s.parse::<f64>().is_ok() {
87+
for &(constant, name, min_digits, msrv) in &KNOWN_CONSTS {
88+
if is_approx_const(constant, &s, min_digits)
89+
&& msrv.as_ref().map_or(true, |msrv| meets_msrv(self.msrv.as_ref(), msrv))
90+
{
91+
span_lint(
92+
cx,
93+
APPROX_CONSTANT,
94+
e.span,
95+
&format!(
96+
"approximate value of `{}::consts::{}` found. \
97+
Consider using it directly",
98+
module, &name
99+
),
100+
);
101+
return;
102+
}
103+
}
104+
}
79105
}
80106
}
81107

82-
fn check_known_consts(cx: &LateContext<'_>, e: &Expr<'_>, s: symbol::Symbol, module: &str) {
83-
let s = s.as_str();
84-
if s.parse::<f64>().is_ok() {
85-
for &(constant, name, min_digits) in &KNOWN_CONSTS {
86-
if is_approx_const(constant, &s, min_digits) {
87-
span_lint(
88-
cx,
89-
APPROX_CONSTANT,
90-
e.span,
91-
&format!(
92-
"approximate value of `{}::consts::{}` found. \
93-
Consider using it directly",
94-
module, &name
95-
),
96-
);
97-
return;
98-
}
108+
impl_lint_pass!(ApproxConstant => [APPROX_CONSTANT]);
109+
110+
impl<'tcx> LateLintPass<'tcx> for ApproxConstant {
111+
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
112+
if let ExprKind::Lit(lit) = &e.kind {
113+
self.check_lit(cx, &lit.node, e);
99114
}
100115
}
116+
117+
extract_msrv_attr!(LateContext);
101118
}
102119

103120
/// Returns `false` if the number of significant figures in `value` are

‎clippy_lints/src/lib.rs

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1865,7 +1865,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
18651865
store.register_late_pass(|| Box::new(needless_bool::NeedlessBool));
18661866
store.register_late_pass(|| Box::new(needless_bool::BoolComparison));
18671867
store.register_late_pass(|| Box::new(needless_for_each::NeedlessForEach));
1868-
store.register_late_pass(|| Box::new(approx_const::ApproxConstant));
18691868
store.register_late_pass(|| Box::new(misc::MiscLints));
18701869
store.register_late_pass(|| Box::new(eta_reduction::EtaReduction));
18711870
store.register_late_pass(|| Box::new(identity_op::IdentityOp));
@@ -1894,6 +1893,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
18941893
});
18951894

18961895
let avoid_breaking_exported_api = conf.avoid_breaking_exported_api;
1896+
store.register_late_pass(move || Box::new(approx_const::ApproxConstant::new(msrv)));
18971897
store.register_late_pass(move || Box::new(methods::Methods::new(avoid_breaking_exported_api, msrv)));
18981898
store.register_late_pass(move || Box::new(matches::Matches::new(msrv)));
18991899
store.register_early_pass(move || Box::new(manual_non_exhaustive::ManualNonExhaustive::new(msrv)));

‎clippy_utils/src/msrvs.rs

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -17,6 +17,7 @@ msrv_aliases! {
1717
1,50,0 { BOOL_THEN }
1818
1,46,0 { CONST_IF_MATCH }
1919
1,45,0 { STR_STRIP_PREFIX }
20+
1,43,0 { LOG2_10, LOG10_2 }
2021
1,42,0 { MATCHES_MACRO }
2122
1,41,0 { RE_REBALANCING_COHERENCE, RESULT_MAP_OR_ELSE }
2223
1,40,0 { MEM_TAKE, NON_EXHAUSTIVE, OPTION_AS_DEREF }

‎tests/ui/min_rust_version_attr.rs

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,11 @@
44

55
use std::ops::{Deref, RangeFrom};
66

7+
fn approx_const() {
8+
let log2_10 = 3.321928094887362;
9+
let log10_2 = 0.301029995663981;
10+
}
11+
712
fn cloned_instead_of_copied() {
813
let _ = [1].iter().cloned();
914
}

‎tests/ui/min_rust_version_attr.stderr

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,12 +1,12 @@
11
error: stripping a prefix manually
2-
--> $DIR/min_rust_version_attr.rs:160:24
2+
--> $DIR/min_rust_version_attr.rs:165:24
33
|
44
LL | assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
55
| ^^^^^^^^^^^^^^^^^^^^
66
|
77
= note: `-D clippy::manual-strip` implied by `-D warnings`
88
note: the prefix was tested here
9-
--> $DIR/min_rust_version_attr.rs:159:9
9+
--> $DIR/min_rust_version_attr.rs:164:9
1010
|
1111
LL | if s.starts_with("hello, ") {
1212
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -17,13 +17,13 @@ LL ~ assert_eq!(<stripped>.to_uppercase(), "WORLD!");
1717
|
1818

1919
error: stripping a prefix manually
20-
--> $DIR/min_rust_version_attr.rs:172:24
20+
--> $DIR/min_rust_version_attr.rs:177:24
2121
|
2222
LL | assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
2323
| ^^^^^^^^^^^^^^^^^^^^
2424
|
2525
note: the prefix was tested here
26-
--> $DIR/min_rust_version_attr.rs:171:9
26+
--> $DIR/min_rust_version_attr.rs:176:9
2727
|
2828
LL | if s.starts_with("hello, ") {
2929
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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