diff --git a/clippy_lints/src/operators/eq_op.rs b/clippy_lints/src/operators/eq_op.rs
index 67913f7392c..78965b7d6f7 100644
--- a/clippy_lints/src/operators/eq_op.rs
+++ b/clippy_lints/src/operators/eq_op.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::span_lint;
+use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
use clippy_utils::macros::{find_assert_eq_args, first_node_macro_backtrace};
use clippy_utils::{ast_utils::is_useless_with_eq_exprs, eq_expr_value, is_in_test_function};
use rustc_hir::{BinOpKind, Expr};
@@ -35,11 +35,16 @@ pub(crate) fn check<'tcx>(
right: &'tcx Expr<'_>,
) {
if is_useless_with_eq_exprs(op.into()) && eq_expr_value(cx, left, right) && !is_in_test_function(cx.tcx, e.hir_id) {
- span_lint(
+ span_lint_and_then(
cx,
EQ_OP,
e.span,
&format!("equal expressions as operands to `{}`", op.as_str()),
+ |diag| {
+ if let BinOpKind::Ne = op && cx.typeck_results().expr_ty(left).is_floating_point() {
+ diag.note("if you intended to check if the operand is NaN, use `.is_nan()` instead");
+ }
+ },
);
}
}
diff --git a/tests/ui/eq_op.rs b/tests/ui/eq_op.rs
index 38372378168..e973e5ba2fb 100644
--- a/tests/ui/eq_op.rs
+++ b/tests/ui/eq_op.rs
@@ -10,6 +10,8 @@ fn main() {
let _ = false != false;
let _ = 1.5 < 1.5;
let _ = 1u64 >= 1u64;
+ let x = f32::NAN;
+ let _ = x != x;
// casts, methods, parentheses
let _ = (1u32 as u64) & (1u32 as u64);
diff --git a/tests/ui/eq_op.stderr b/tests/ui/eq_op.stderr
index 2c013b6b6fe..c7fa253bdca 100644
--- a/tests/ui/eq_op.stderr
+++ b/tests/ui/eq_op.stderr
@@ -30,143 +30,151 @@ error: equal expressions as operands to `>=`
LL | let _ = 1u64 >= 1u64;
| ^^^^^^^^^^^^
+error: equal expressions as operands to `!=`
+ --> $DIR/eq_op.rs:14:13
+ |
+LL | let _ = x != x;
+ | ^^^^^^
+ |
+ = note: if you intended to check if the operand is NaN, use `.is_nan()` instead
+
error: equal expressions as operands to `&`
- --> $DIR/eq_op.rs:15:13
+ --> $DIR/eq_op.rs:17:13
|
LL | let _ = (1u32 as u64) & (1u32 as u64);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `^`
- --> $DIR/eq_op.rs:18:17
+ --> $DIR/eq_op.rs:20:17
|
LL | let _ = 1 ^ ((((((1))))));
| ^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `<`
- --> $DIR/eq_op.rs:22:13
+ --> $DIR/eq_op.rs:24:13
|
LL | let _ = (-(2) < -(2));
| ^^^^^^^^^^^^^
error: equal expressions as operands to `==`
- --> $DIR/eq_op.rs:23:13
+ --> $DIR/eq_op.rs:25:13
|
LL | let _ = ((1 + 1) & (1 + 1) == (1 + 1) & (1 + 1));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `&`
- --> $DIR/eq_op.rs:23:14
+ --> $DIR/eq_op.rs:25:14
|
LL | let _ = ((1 + 1) & (1 + 1) == (1 + 1) & (1 + 1));
| ^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `&`
- --> $DIR/eq_op.rs:23:35
+ --> $DIR/eq_op.rs:25:35
|
LL | let _ = ((1 + 1) & (1 + 1) == (1 + 1) & (1 + 1));
| ^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `==`
- --> $DIR/eq_op.rs:24:13
+ --> $DIR/eq_op.rs:26:13
|
LL | let _ = (1 * 2) + (3 * 4) == 1 * 2 + 3 * 4;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `!=`
- --> $DIR/eq_op.rs:27:13
+ --> $DIR/eq_op.rs:29:13
|
LL | let _ = ([1] != [1]);
| ^^^^^^^^^^^^
error: equal expressions as operands to `!=`
- --> $DIR/eq_op.rs:28:13
+ --> $DIR/eq_op.rs:30:13
|
LL | let _ = ((1, 2) != (1, 2));
| ^^^^^^^^^^^^^^^^^^
error: equal expressions as operands to `==`
- --> $DIR/eq_op.rs:32:13
+ --> $DIR/eq_op.rs:34:13
|
LL | let _ = 1 + 1 == 2;
| ^^^^^^^^^^
error: equal expressions as operands to `==`
- --> $DIR/eq_op.rs:33:13
+ --> $DIR/eq_op.rs:35:13
|
LL | let _ = 1 - 1 == 0;
| ^^^^^^^^^^
error: equal expressions as operands to `-`
- --> $DIR/eq_op.rs:33:13
+ --> $DIR/eq_op.rs:35:13
|
LL | let _ = 1 - 1 == 0;
| ^^^^^
error: equal expressions as operands to `-`
- --> $DIR/eq_op.rs:35:13
+ --> $DIR/eq_op.rs:37:13
|
LL | let _ = 1 - 1;
| ^^^^^
error: equal expressions as operands to `/`
- --> $DIR/eq_op.rs:36:13
+ --> $DIR/eq_op.rs:38:13
|
LL | let _ = 1 / 1;
| ^^^^^
error: equal expressions as operands to `&&`
- --> $DIR/eq_op.rs:37:13
+ --> $DIR/eq_op.rs:39:13
|
LL | let _ = true && true;
| ^^^^^^^^^^^^
error: equal expressions as operands to `||`
- --> $DIR/eq_op.rs:39:13
+ --> $DIR/eq_op.rs:41:13
|
LL | let _ = true || true;
| ^^^^^^^^^^^^
error: equal expressions as operands to `&&`
- --> $DIR/eq_op.rs:44:13
+ --> $DIR/eq_op.rs:46:13
|
LL | let _ = a == b && b == a;
| ^^^^^^^^^^^^^^^^
error: equal expressions as operands to `&&`
- --> $DIR/eq_op.rs:45:13
+ --> $DIR/eq_op.rs:47:13
|
LL | let _ = a != b && b != a;
| ^^^^^^^^^^^^^^^^
error: equal expressions as operands to `&&`
- --> $DIR/eq_op.rs:46:13
+ --> $DIR/eq_op.rs:48:13
|
LL | let _ = a < b && b > a;
| ^^^^^^^^^^^^^^
error: equal expressions as operands to `&&`
- --> $DIR/eq_op.rs:47:13
+ --> $DIR/eq_op.rs:49:13
|
LL | let _ = a <= b && b >= a;
| ^^^^^^^^^^^^^^^^
error: equal expressions as operands to `==`
- --> $DIR/eq_op.rs:50:13
+ --> $DIR/eq_op.rs:52:13
|
LL | let _ = a == a;
| ^^^^^^
error: equal expressions as operands to `/`
- --> $DIR/eq_op.rs:60:20
+ --> $DIR/eq_op.rs:62:20
|
LL | const D: u32 = A / A;
| ^^^^^
error: equal expressions as operands to `==`
- --> $DIR/eq_op.rs:91:5
+ --> $DIR/eq_op.rs:93:5
|
LL | (n1.inner.0).0 == (n1.inner.0).0 && (n1.inner.1).0 == (n2.inner.1).0 && (n1.inner.2).0 == (n2.inner.2).0
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-error: aborting due to 28 previous errors
+error: aborting due to 29 previous errors