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Make approx_const MSRV aware

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Fixes #7623.
This commit is contained in:
Michael Wright 2021-09-03 08:34:34 +02:00
parent 265b8ec622
commit a23af89447
5 changed files with 83 additions and 60 deletions
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127
clippy_lints/src/approx_const.rs
View file

@ -1,8 +1,10 @@
use clippy_utils::diagnostics::span_lint;
use clippy_utils::{meets_msrv, msrvs};
use rustc_ast::ast::{FloatTy, LitFloatType, LitKind};
use rustc_hir::{Expr, ExprKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::symbol;
use std::f64::consts as f64;
@ -36,68 +38,83 @@ declare_clippy_lint! {
"the approximate of a known float constant (in `std::fXX::consts`)"
}
// Tuples are of the form (constant, name, min_digits)
const KNOWN_CONSTS: [(f64, &str, usize); 18] = [
(f64::E, "E", 4),
(f64::FRAC_1_PI, "FRAC_1_PI", 4),
(f64::FRAC_1_SQRT_2, "FRAC_1_SQRT_2", 5),
(f64::FRAC_2_PI, "FRAC_2_PI", 5),
(f64::FRAC_2_SQRT_PI, "FRAC_2_SQRT_PI", 5),
(f64::FRAC_PI_2, "FRAC_PI_2", 5),
(f64::FRAC_PI_3, "FRAC_PI_3", 5),
(f64::FRAC_PI_4, "FRAC_PI_4", 5),
(f64::FRAC_PI_6, "FRAC_PI_6", 5),
(f64::FRAC_PI_8, "FRAC_PI_8", 5),
(f64::LN_2, "LN_2", 5),
(f64::LN_10, "LN_10", 5),
(f64::LOG2_10, "LOG2_10", 5),
(f64::LOG2_E, "LOG2_E", 5),
(f64::LOG10_2, "LOG10_2", 5),
(f64::LOG10_E, "LOG10_E", 5),
(f64::PI, "PI", 3),
(f64::SQRT_2, "SQRT_2", 5),
// Tuples are of the form (constant, name, min_digits, msrv)
const KNOWN_CONSTS: [(f64, &str, usize, Option<RustcVersion>); 18] = [
(f64::E, "E", 4, None),
(f64::FRAC_1_PI, "FRAC_1_PI", 4, None),
(f64::FRAC_1_SQRT_2, "FRAC_1_SQRT_2", 5, None),
(f64::FRAC_2_PI, "FRAC_2_PI", 5, None),
(f64::FRAC_2_SQRT_PI, "FRAC_2_SQRT_PI", 5, None),
(f64::FRAC_PI_2, "FRAC_PI_2", 5, None),
(f64::FRAC_PI_3, "FRAC_PI_3", 5, None),
(f64::FRAC_PI_4, "FRAC_PI_4", 5, None),
(f64::FRAC_PI_6, "FRAC_PI_6", 5, None),
(f64::FRAC_PI_8, "FRAC_PI_8", 5, None),
(f64::LN_2, "LN_2", 5, None),
(f64::LN_10, "LN_10", 5, None),
(f64::LOG2_10, "LOG2_10", 5, Some(msrvs::LOG2_10)),
(f64::LOG2_E, "LOG2_E", 5, None),
(f64::LOG10_2, "LOG10_2", 5, Some(msrvs::LOG10_2)),
(f64::LOG10_E, "LOG10_E", 5, None),
(f64::PI, "PI", 3, None),
(f64::SQRT_2, "SQRT_2", 5, None),
];
declare_lint_pass!(ApproxConstant => [APPROX_CONSTANT]);
pub struct ApproxConstant {
msrv: Option<RustcVersion>,
}
impl ApproxConstant {
#[must_use]
pub fn new(msrv: Option<RustcVersion>) -> Self {
Self { msrv }
}
fn check_lit(&self, cx: &LateContext<'_>, lit: &LitKind, e: &Expr<'_>) {
match *lit {
LitKind::Float(s, LitFloatType::Suffixed(fty)) => match fty {
FloatTy::F32 => self.check_known_consts(cx, e, s, "f32"),
FloatTy::F64 => self.check_known_consts(cx, e, s, "f64"),
},
LitKind::Float(s, LitFloatType::Unsuffixed) => self.check_known_consts(cx, e, s, "f{32, 64}"),
_ => (),
}
}
fn check_known_consts(&self, cx: &LateContext<'_>, e: &Expr<'_>, s: symbol::Symbol, module: &str) {
let s = s.as_str();
if s.parse::<f64>().is_ok() {
for &(constant, name, min_digits, msrv) in &KNOWN_CONSTS {
if is_approx_const(constant, &s, min_digits)
&& msrv.as_ref().map_or(true, |msrv| meets_msrv(self.msrv.as_ref(), msrv))
{
span_lint(
cx,
APPROX_CONSTANT,
e.span,
&format!(
"approximate value of `{}::consts::{}` found. \
Consider using it directly",
module, &name
),
);
return;
}
}
}
}
}
impl_lint_pass!(ApproxConstant => [APPROX_CONSTANT]);
impl<'tcx> LateLintPass<'tcx> for ApproxConstant {
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
if let ExprKind::Lit(lit) = &e.kind {
check_lit(cx, &lit.node, e);
self.check_lit(cx, &lit.node, e);
}
}
}
fn check_lit(cx: &LateContext<'_>, lit: &LitKind, e: &Expr<'_>) {
match *lit {
LitKind::Float(s, LitFloatType::Suffixed(fty)) => match fty {
FloatTy::F32 => check_known_consts(cx, e, s, "f32"),
FloatTy::F64 => check_known_consts(cx, e, s, "f64"),
},
LitKind::Float(s, LitFloatType::Unsuffixed) => check_known_consts(cx, e, s, "f{32, 64}"),
_ => (),
}
}
fn check_known_consts(cx: &LateContext<'_>, e: &Expr<'_>, s: symbol::Symbol, module: &str) {
let s = s.as_str();
if s.parse::<f64>().is_ok() {
for &(constant, name, min_digits) in &KNOWN_CONSTS {
if is_approx_const(constant, &s, min_digits) {
span_lint(
cx,
APPROX_CONSTANT,
e.span,
&format!(
"approximate value of `{}::consts::{}` found. \
Consider using it directly",
module, &name
),
);
return;
}
}
}
extract_msrv_attr!(LateContext);
}
/// Returns `false` if the number of significant figures in `value` are

2
clippy_lints/src/lib.rs
View file

@ -1865,7 +1865,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
store.register_late_pass(|| Box::new(needless_bool::NeedlessBool));
store.register_late_pass(|| Box::new(needless_bool::BoolComparison));
store.register_late_pass(|| Box::new(needless_for_each::NeedlessForEach));
store.register_late_pass(|| Box::new(approx_const::ApproxConstant));
store.register_late_pass(|| Box::new(misc::MiscLints));
store.register_late_pass(|| Box::new(eta_reduction::EtaReduction));
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:
});
let avoid_breaking_exported_api = conf.avoid_breaking_exported_api;
store.register_late_pass(move || Box::new(approx_const::ApproxConstant::new(msrv)));
store.register_late_pass(move || Box::new(methods::Methods::new(avoid_breaking_exported_api, msrv)));
store.register_late_pass(move || Box::new(matches::Matches::new(msrv)));
store.register_early_pass(move || Box::new(manual_non_exhaustive::ManualNonExhaustive::new(msrv)));

1
clippy_utils/src/msrvs.rs
View file

@ -17,6 +17,7 @@ msrv_aliases! {
1,50,0 { BOOL_THEN }
1,46,0 { CONST_IF_MATCH }
1,45,0 { STR_STRIP_PREFIX }
1,43,0 { LOG2_10, LOG10_2 }
1,42,0 { MATCHES_MACRO }
1,41,0 { RE_REBALANCING_COHERENCE, RESULT_MAP_OR_ELSE }
1,40,0 { MEM_TAKE, NON_EXHAUSTIVE, OPTION_AS_DEREF }

5
tests/ui/min_rust_version_attr.rs
View file

@ -4,6 +4,11 @@
use std::ops::{Deref, RangeFrom};
fn approx_const() {
let log2_10 = 3.321928094887362;
let log10_2 = 0.301029995663981;
}
fn cloned_instead_of_copied() {
let _ = [1].iter().cloned();
}

8
tests/ui/min_rust_version_attr.stderr
View file

@ -1,12 +1,12 @@
error: stripping a prefix manually
--> $DIR/min_rust_version_attr.rs:160:24
--> $DIR/min_rust_version_attr.rs:165:24
|
LL | assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
| ^^^^^^^^^^^^^^^^^^^^
|
= note: `-D clippy::manual-strip` implied by `-D warnings`
note: the prefix was tested here
--> $DIR/min_rust_version_attr.rs:159:9
--> $DIR/min_rust_version_attr.rs:164:9
|
LL | if s.starts_with("hello, ") {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -17,13 +17,13 @@ LL ~ assert_eq!(<stripped>.to_uppercase(), "WORLD!");
|
error: stripping a prefix manually
--> $DIR/min_rust_version_attr.rs:172:24
--> $DIR/min_rust_version_attr.rs:177:24
|
LL | assert_eq!(s["hello, ".len()..].to_uppercase(), "WORLD!");
| ^^^^^^^^^^^^^^^^^^^^
|
note: the prefix was tested here
--> $DIR/min_rust_version_attr.rs:171:9
--> $DIR/min_rust_version_attr.rs:176:9
|
LL | if s.starts_with("hello, ") {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^