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Don't lint CStr literals, do lint float literals in redundant_guards (
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rust-lang#13698)

Two changes to `redundant_guards`:

- Lint float literals. We used to do that before but that was changed in
rust-lang#11305 because at the time there was a future compat warning and it was
planned to make pattern matching floats a hard error.

In rust-lang#116284 it was decided to actually remove the lint and
only make matching `NAN` specifically a hard error. The `NAN` part isn't
relevant/important here because this PR only changes what literals are
warned and `f64::NAN` isn't a literal, but I've added a test anyway to
make sure we continue to not lint there.
- Don't lint CStr literals because that can't be a pattern right now
(fixes rust-lang#13681)

changelog: none
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@Centri3
Centri3 authored Nov 17, 2024
2 parents 5f05ce4 + 8859847 commit 8698c31
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Showing 4 changed files with 78 additions and 41 deletions.
7 changes: 1 addition & 6 deletions clippy_lints/src/matches/redundant_guards.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -243,11 +243,6 @@ fn emit_redundant_guards<'tcx>(
}

/// Checks if the given `Expr` can also be represented as a `Pat`.
///
/// All literals generally also work as patterns, however float literals are special.
/// They are currently (as of 2023/08/08) still allowed in patterns, but that will become
/// an error in the future, and rustc already actively warns against this (see rust#41620),
/// so we don't consider those as usable within patterns for linting purposes.
fn expr_can_be_pat(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
for_each_expr_without_closures(expr, |expr| {
if match expr.kind {
Expand All @@ -267,7 +262,7 @@ fn expr_can_be_pat(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
| ExprKind::Tup(..)
| ExprKind::Struct(..)
| ExprKind::Unary(UnOp::Neg, _) => true,
ExprKind::Lit(lit) if !matches!(lit.node, LitKind::Float(..)) => true,
ExprKind::Lit(lit) if !matches!(lit.node, LitKind::CStr(..)) => true,
_ => false,
} {
return ControlFlow::Continue(());
Expand Down
15 changes: 12 additions & 3 deletions tests/ui/redundant_guards.fixed
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
//@aux-build:proc_macros.rs
#![feature(if_let_guard)]
#![allow(clippy::no_effect, unused, clippy::single_match)]
#![allow(clippy::no_effect, unused, clippy::single_match, invalid_nan_comparisons)]
#![warn(clippy::redundant_guards)]

#[macro_use]
Expand All @@ -19,15 +19,24 @@ struct FloatWrapper(f32);

fn issue11304() {
match 0.1 {
x if x == 0.0 => todo!(),
0.0 => todo!(),
// Pattern matching NAN is illegal
x if x == f64::NAN => todo!(),
_ => todo!(),
}
match FloatWrapper(0.1) {
x if x == FloatWrapper(0.0) => todo!(),
FloatWrapper(0.0) => todo!(),
_ => todo!(),
}
}

fn issue13681() {
match c"hi" {
x if x == c"hi" => (),
_ => (),
}
}

fn main() {
let c = C(1, 2);
match c {
Expand Down
11 changes: 10 additions & 1 deletion tests/ui/redundant_guards.rs
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
//@aux-build:proc_macros.rs
#![feature(if_let_guard)]
#![allow(clippy::no_effect, unused, clippy::single_match)]
#![allow(clippy::no_effect, unused, clippy::single_match, invalid_nan_comparisons)]
#![warn(clippy::redundant_guards)]

#[macro_use]
Expand All @@ -20,6 +20,8 @@ struct FloatWrapper(f32);
fn issue11304() {
match 0.1 {
x if x == 0.0 => todo!(),
// Pattern matching NAN is illegal
x if x == f64::NAN => todo!(),
_ => todo!(),
}
match FloatWrapper(0.1) {
Expand All @@ -28,6 +30,13 @@ fn issue11304() {
}
}

fn issue13681() {
match c"hi" {
x if x == c"hi" => (),
_ => (),
}
}

fn main() {
let c = C(1, 2);
match c {
Expand Down
86 changes: 55 additions & 31 deletions tests/ui/redundant_guards.stderr
View file
Original file line number Diff line number Diff line change
@@ -1,19 +1,43 @@
error: redundant guard
--> tests/ui/redundant_guards.rs:34:20
--> tests/ui/redundant_guards.rs:22:14
|
LL | C(x, y) if let 1 = y => ..,
| ^^^^^^^^^
LL | x if x == 0.0 => todo!(),
| ^^^^^^^^
|
= note: `-D clippy::redundant-guards` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::redundant_guards)]`
help: try
|
LL - x if x == 0.0 => todo!(),
LL + 0.0 => todo!(),
|

error: redundant guard
--> tests/ui/redundant_guards.rs:28:14
|
LL | x if x == FloatWrapper(0.0) => todo!(),
| ^^^^^^^^^^^^^^^^^^^^^^
|
help: try
|
LL - x if x == FloatWrapper(0.0) => todo!(),
LL + FloatWrapper(0.0) => todo!(),
|

error: redundant guard
--> tests/ui/redundant_guards.rs:43:20
|
LL | C(x, y) if let 1 = y => ..,
| ^^^^^^^^^
|
help: try
|
LL - C(x, y) if let 1 = y => ..,
LL + C(x, 1) => ..,
|

error: redundant guard
--> tests/ui/redundant_guards.rs:40:20
--> tests/ui/redundant_guards.rs:49:20
|
LL | Some(x) if matches!(x, Some(1) if true) => ..,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Expand All @@ -24,7 +48,7 @@ LL | Some(Some(1)) if true => ..,
| ~~~~~~~ ~~~~~~~

error: redundant guard
--> tests/ui/redundant_guards.rs:41:20
--> tests/ui/redundant_guards.rs:50:20
|
LL | Some(x) if matches!(x, Some(1)) => {
| ^^^^^^^^^^^^^^^^^^^^
Expand All @@ -36,7 +60,7 @@ LL + Some(Some(1)) => {
|

error: redundant guard
--> tests/ui/redundant_guards.rs:45:20
--> tests/ui/redundant_guards.rs:54:20
|
LL | Some(x) if let Some(1) = x => ..,
| ^^^^^^^^^^^^^^^
Expand All @@ -48,7 +72,7 @@ LL + Some(Some(1)) => ..,
|

error: redundant guard
--> tests/ui/redundant_guards.rs:46:20
--> tests/ui/redundant_guards.rs:55:20
|
LL | Some(x) if x == Some(2) => ..,
| ^^^^^^^^^^^^
Expand All @@ -60,7 +84,7 @@ LL + Some(Some(2)) => ..,
|

error: redundant guard
--> tests/ui/redundant_guards.rs:47:20
--> tests/ui/redundant_guards.rs:56:20
|
LL | Some(x) if Some(2) == x => ..,
| ^^^^^^^^^^^^
Expand All @@ -72,7 +96,7 @@ LL + Some(Some(2)) => ..,
|

error: redundant guard
--> tests/ui/redundant_guards.rs:72:20
--> tests/ui/redundant_guards.rs:81:20
|
LL | B { e } if matches!(e, Some(A(2))) => ..,
| ^^^^^^^^^^^^^^^^^^^^^^^
Expand All @@ -84,7 +108,7 @@ LL + B { e: Some(A(2)) } => ..,
|

error: redundant guard
--> tests/ui/redundant_guards.rs:109:20
--> tests/ui/redundant_guards.rs:118:20
|
LL | E::A(y) if y == "not from an or pattern" => {},
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Expand All @@ -96,7 +120,7 @@ LL + E::A("not from an or pattern") => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:116:14
--> tests/ui/redundant_guards.rs:125:14
|
LL | x if matches!(x, Some(0)) => ..,
| ^^^^^^^^^^^^^^^^^^^^
Expand All @@ -108,7 +132,7 @@ LL + Some(0) => ..,
|

error: redundant guard
--> tests/ui/redundant_guards.rs:123:14
--> tests/ui/redundant_guards.rs:132:14
|
LL | i if i == -1 => {},
| ^^^^^^^
Expand All @@ -120,7 +144,7 @@ LL + -1 => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:124:14
--> tests/ui/redundant_guards.rs:133:14
|
LL | i if i == 1 => {},
| ^^^^^^
Expand All @@ -132,7 +156,7 @@ LL + 1 => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:186:28
--> tests/ui/redundant_guards.rs:195:28
|
LL | Some(ref x) if x == &1 => {},
| ^^^^^^^
Expand All @@ -144,7 +168,7 @@ LL + Some(1) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:187:28
--> tests/ui/redundant_guards.rs:196:28
|
LL | Some(ref x) if &1 == x => {},
| ^^^^^^^
Expand All @@ -156,7 +180,7 @@ LL + Some(1) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:188:28
--> tests/ui/redundant_guards.rs:197:28
|
LL | Some(ref x) if let &2 = x => {},
| ^^^^^^^^^^
Expand All @@ -168,7 +192,7 @@ LL + Some(2) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:189:28
--> tests/ui/redundant_guards.rs:198:28
|
LL | Some(ref x) if matches!(x, &3) => {},
| ^^^^^^^^^^^^^^^
Expand All @@ -180,7 +204,7 @@ LL + Some(3) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:209:32
--> tests/ui/redundant_guards.rs:218:32
|
LL | B { ref c, .. } if c == &1 => {},
| ^^^^^^^
Expand All @@ -192,7 +216,7 @@ LL + B { c: 1, .. } => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:210:32
--> tests/ui/redundant_guards.rs:219:32
|
LL | B { ref c, .. } if &1 == c => {},
| ^^^^^^^
Expand All @@ -204,7 +228,7 @@ LL + B { c: 1, .. } => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:211:32
--> tests/ui/redundant_guards.rs:220:32
|
LL | B { ref c, .. } if let &1 = c => {},
| ^^^^^^^^^^
Expand All @@ -216,7 +240,7 @@ LL + B { c: 1, .. } => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:212:32
--> tests/ui/redundant_guards.rs:221:32
|
LL | B { ref c, .. } if matches!(c, &1) => {},
| ^^^^^^^^^^^^^^^
Expand All @@ -228,7 +252,7 @@ LL + B { c: 1, .. } => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:222:26
--> tests/ui/redundant_guards.rs:231:26
|
LL | Some(Some(x)) if x.is_empty() => {},
| ^^^^^^^^^^^^
Expand All @@ -240,7 +264,7 @@ LL + Some(Some("")) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:233:26
--> tests/ui/redundant_guards.rs:242:26
|
LL | Some(Some(x)) if x.is_empty() => {},
| ^^^^^^^^^^^^
Expand All @@ -252,7 +276,7 @@ LL + Some(Some([])) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:238:26
--> tests/ui/redundant_guards.rs:247:26
|
LL | Some(Some(x)) if x.is_empty() => {},
| ^^^^^^^^^^^^
Expand All @@ -264,7 +288,7 @@ LL + Some(Some([])) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:249:26
--> tests/ui/redundant_guards.rs:258:26
|
LL | Some(Some(x)) if x.starts_with(&[]) => {},
| ^^^^^^^^^^^^^^^^^^
Expand All @@ -276,7 +300,7 @@ LL + Some(Some([..])) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:254:26
--> tests/ui/redundant_guards.rs:263:26
|
LL | Some(Some(x)) if x.starts_with(&[1]) => {},
| ^^^^^^^^^^^^^^^^^^^
Expand All @@ -288,7 +312,7 @@ LL + Some(Some([1, ..])) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:259:26
--> tests/ui/redundant_guards.rs:268:26
|
LL | Some(Some(x)) if x.starts_with(&[1, 2]) => {},
| ^^^^^^^^^^^^^^^^^^^^^^
Expand All @@ -300,7 +324,7 @@ LL + Some(Some([1, 2, ..])) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:264:26
--> tests/ui/redundant_guards.rs:273:26
|
LL | Some(Some(x)) if x.ends_with(&[1, 2]) => {},
| ^^^^^^^^^^^^^^^^^^^^
Expand All @@ -312,7 +336,7 @@ LL + Some(Some([.., 1, 2])) => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:286:18
--> tests/ui/redundant_guards.rs:295:18
|
LL | y if y.is_empty() => {},
| ^^^^^^^^^^^^
Expand All @@ -324,7 +348,7 @@ LL + "" => {},
|

error: redundant guard
--> tests/ui/redundant_guards.rs:305:22
--> tests/ui/redundant_guards.rs:314:22
|
LL | y if y.is_empty() => {},
| ^^^^^^^^^^^^
Expand All @@ -335,5 +359,5 @@ LL - y if y.is_empty() => {},
LL + "" => {},
|

error: aborting due to 28 previous errors
error: aborting due to 30 previous errors

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