Add float cmp tests for arrays

Author: marcin-serwin

tests/ui/float_cmp.rs

@@ -1,5 +1,11 @@
 #![warn(clippy::float_cmp)]
-#![allow(unused, clippy::no_effect, clippy::unnecessary_operation, clippy::cast_lossless)]
+#![allow(
+    unused,
+    clippy::no_effect,
+    clippy::unnecessary_operation,
+    clippy::cast_lossless,
+    clippy::many_single_char_names
+)]
 
 use std::ops::Add;
 
@@ -77,12 +83,20 @@ fn main() {
 
     assert_eq!(a, b); // no errors
 
+    const ZERO_ARRAY: [f32; 2] = [0.0, 0.0];
+    const NON_ZERO_ARRAY: [f32; 2] = [0.0, 0.1];
+
+    let i = 0;
+    let j = 1;
+
+    ZERO_ARRAY[i] == NON_ZERO_ARRAY[j]; // ok, because lhs is zero regardless of i
+    NON_ZERO_ARRAY[i] == NON_ZERO_ARRAY[j];
+
     let a1: [f32; 1] = [0.0];
     let a2: [f32; 1] = [1.1];
 
-    assert_eq!(a1[0], a2[0]);
-
-    assert_eq!(&a1[0], &a2[0]);
+    a1 == a2;
+    a1[0] == a2[0];
 
     // no errors - comparing signums is ok
     let x32 = 3.21f32;

tests/ui/float_cmp.stderr

@@ -1,65 +1,75 @@
 error: strict comparison of `f32` or `f64`
-  --> $DIR/float_cmp.rs:59:5
+  --> $DIR/float_cmp.rs:65:5
    |
 LL |     ONE as f64 != 2.0;
    |     ^^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(ONE as f64 - 2.0).abs() > error`
    |
    = note: `-D clippy::float-cmp` implied by `-D warnings`
 note: `f32::EPSILON` and `f64::EPSILON` are available.
-  --> $DIR/float_cmp.rs:59:5
+  --> $DIR/float_cmp.rs:65:5
    |
 LL |     ONE as f64 != 2.0;
    |     ^^^^^^^^^^^^^^^^^
 
 error: strict comparison of `f32` or `f64`
-  --> $DIR/float_cmp.rs:64:5
+  --> $DIR/float_cmp.rs:70:5
    |
 LL |     x == 1.0;
    |     ^^^^^^^^ help: consider comparing them within some error: `(x - 1.0).abs() < error`
    |
 note: `f32::EPSILON` and `f64::EPSILON` are available.
-  --> $DIR/float_cmp.rs:64:5
+  --> $DIR/float_cmp.rs:70:5
    |
 LL |     x == 1.0;
    |     ^^^^^^^^
 
 error: strict comparison of `f32` or `f64`
-  --> $DIR/float_cmp.rs:67:5
+  --> $DIR/float_cmp.rs:73:5
    |
 LL |     twice(x) != twice(ONE as f64);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(twice(x) - twice(ONE as f64)).abs() > error`
    |
 note: `f32::EPSILON` and `f64::EPSILON` are available.
-  --> $DIR/float_cmp.rs:67:5
+  --> $DIR/float_cmp.rs:73:5
    |
 LL |     twice(x) != twice(ONE as f64);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: strict comparison of `f32` or `f64`
-  --> $DIR/float_cmp.rs:83:5
+  --> $DIR/float_cmp.rs:93:5
    |
-LL |     assert_eq!(a1[0], a2[0]);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     NON_ZERO_ARRAY[i] == NON_ZERO_ARRAY[j];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(NON_ZERO_ARRAY[i] - NON_ZERO_ARRAY[j]).abs() < error`
    |
-note: `std::f32::EPSILON` and `std::f64::EPSILON` are available.
-  --> $DIR/float_cmp.rs:83:5
+note: `f32::EPSILON` and `f64::EPSILON` are available.
+  --> $DIR/float_cmp.rs:93:5
+   |
+LL |     NON_ZERO_ARRAY[i] == NON_ZERO_ARRAY[j];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: strict comparison of `f32` or `f64`
+  --> $DIR/float_cmp.rs:98:5
+   |
+LL |     a1 == a2;
+   |     ^^^^^^^^
+   |
+note: `f32::EPSILON` and `f64::EPSILON` are available.
+  --> $DIR/float_cmp.rs:98:5
    |
-LL |     assert_eq!(a1[0], a2[0]);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+LL |     a1 == a2;
+   |     ^^^^^^^^
 
 error: strict comparison of `f32` or `f64`
-  --> $DIR/float_cmp.rs:85:5
+  --> $DIR/float_cmp.rs:99:5
    |
-LL |     assert_eq!(&a1[0], &a2[0]);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |     a1[0] == a2[0];
+   |     ^^^^^^^^^^^^^^ help: consider comparing them within some error: `(a1[0] - a2[0]).abs() < error`
    |
-note: `std::f32::EPSILON` and `std::f64::EPSILON` are available.
-  --> $DIR/float_cmp.rs:85:5
+note: `f32::EPSILON` and `f64::EPSILON` are available.
+  --> $DIR/float_cmp.rs:99:5
    |
-LL |     assert_eq!(&a1[0], &a2[0]);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+LL |     a1[0] == a2[0];
+   |     ^^^^^^^^^^^^^^
 
-error: aborting due to 5 previous errors
+error: aborting due to 6 previous errors