Auto merge of #6043 - HaramanJohal:margin_of_error, r=matthiaskrgr

clarify margin of error in wording of float comparison operator lint messages

fixes #6040

changelog: change wording of float comparison operator to make margin of error less ambiguous

3 files changed, 36 insertions, 36 deletions

diff --git a/clippy_lints/src/misc.rs b/clippy_lints/src/misc.rs
index d4a50dd9013..67a3685fd0d 100644
--- a/clippy_lints/src/misc.rs
+++ b/clippy_lints/src/misc.rs
@@ -99,11 +99,11 @@ declare_clippy_lint! {
     /// if y != x {} // where both are floats
     ///
     /// // Good
-    /// let error = f64::EPSILON; // Use an epsilon for comparison
+    /// let error_margin = f64::EPSILON; // Use an epsilon for comparison
     /// // Or, if Rust <= 1.42, use `std::f64::EPSILON` constant instead.
-    /// // let error = std::f64::EPSILON;
-    /// if (y - 1.23f64).abs() < error { }
-    /// if (y - x).abs() > error { }
+    /// // let error_margin = std::f64::EPSILON;
+    /// if (y - 1.23f64).abs() < error_margin { }
+    /// if (y - x).abs() > error_margin { }
     /// ```
     pub FLOAT_CMP,
     correctness,
@@ -242,10 +242,10 @@ declare_clippy_lint! {
     /// if x == ONE { } // where both are floats
     ///
     /// // Good
-    /// let error = f64::EPSILON; // Use an epsilon for comparison
+    /// let error_margin = f64::EPSILON; // Use an epsilon for comparison
     /// // Or, if Rust <= 1.42, use `std::f64::EPSILON` constant instead.
-    /// // let error = std::f64::EPSILON;
-    /// if (x - ONE).abs() < error { }
+    /// // let error_margin = std::f64::EPSILON;
+    /// if (x - ONE).abs() < error_margin { }
     /// ```
     pub FLOAT_CMP_CONST,
     restriction,
@@ -411,16 +411,16 @@ impl<'tcx> LateLintPass<'tcx> for MiscLints {
                         if !is_comparing_arrays {
                             diag.span_suggestion(
                                 expr.span,
-                                "consider comparing them within some error",
+                                "consider comparing them within some margin of error",
                                 format!(
-                                    "({}).abs() {} error",
+                                    "({}).abs() {} error_margin",
                                     lhs - rhs,
                                     if op == BinOpKind::Eq { '<' } else { '>' }
                                 ),
                                 Applicability::HasPlaceholders, // snippet
                             );
                         }
-                        diag.note("`f32::EPSILON` and `f64::EPSILON` are available for the `error`");
+                        diag.note("`f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`");
                     });
                 } else if op == BinOpKind::Rem && is_integer_const(cx, right, 1) {
                     span_lint(cx, MODULO_ONE, expr.span, "any number modulo 1 will be 0");
diff --git a/tests/ui/float_cmp.stderr b/tests/ui/float_cmp.stderr
index 2d454e8e70d..f7c380fc915 100644
--- a/tests/ui/float_cmp.stderr
+++ b/tests/ui/float_cmp.stderr
@@ -2,34 +2,34 @@ error: strict comparison of `f32` or `f64`
   --> $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`
+   |     ^^^^^^^^^^^^^^^^^ help: consider comparing them within some margin of error: `(ONE as f64 - 2.0).abs() > error_margin`
    |
    = note: `-D clippy::float-cmp` implied by `-D warnings`
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64`
   --> $DIR/float_cmp.rs:70:5
    |
 LL |     x == 1.0;
-   |     ^^^^^^^^ help: consider comparing them within some error: `(x - 1.0).abs() < error`
+   |     ^^^^^^^^ help: consider comparing them within some margin of error: `(x - 1.0).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64`
   --> $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`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider comparing them within some margin of error: `(twice(x) - twice(ONE as f64)).abs() > error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64`
   --> $DIR/float_cmp.rs:93:5
    |
 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`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider comparing them within some margin of error: `(NON_ZERO_ARRAY[i] - NON_ZERO_ARRAY[j]).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` arrays
   --> $DIR/float_cmp.rs:98:5
@@ -37,15 +37,15 @@ error: strict comparison of `f32` or `f64` arrays
 LL |     a1 == a2;
    |     ^^^^^^^^
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64`
   --> $DIR/float_cmp.rs:99:5
    |
 LL |     a1[0] == a2[0];
-   |     ^^^^^^^^^^^^^^ help: consider comparing them within some error: `(a1[0] - a2[0]).abs() < error`
+   |     ^^^^^^^^^^^^^^ help: consider comparing them within some margin of error: `(a1[0] - a2[0]).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: aborting due to 6 previous errors
 
diff --git a/tests/ui/float_cmp_const.stderr b/tests/ui/float_cmp_const.stderr
index 19dc4a284b7..5d0455363e8 100644
--- a/tests/ui/float_cmp_const.stderr
+++ b/tests/ui/float_cmp_const.stderr
@@ -2,58 +2,58 @@ error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:20:5
    |
 LL |     1f32 == ONE;
-   |     ^^^^^^^^^^^ help: consider comparing them within some error: `(1f32 - ONE).abs() < error`
+   |     ^^^^^^^^^^^ help: consider comparing them within some margin of error: `(1f32 - ONE).abs() < error_margin`
    |
    = note: `-D clippy::float-cmp-const` implied by `-D warnings`
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:21:5
    |
 LL |     TWO == ONE;
-   |     ^^^^^^^^^^ help: consider comparing them within some error: `(TWO - ONE).abs() < error`
+   |     ^^^^^^^^^^ help: consider comparing them within some margin of error: `(TWO - ONE).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:22:5
    |
 LL |     TWO != ONE;
-   |     ^^^^^^^^^^ help: consider comparing them within some error: `(TWO - ONE).abs() > error`
+   |     ^^^^^^^^^^ help: consider comparing them within some margin of error: `(TWO - ONE).abs() > error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:23:5
    |
 LL |     ONE + ONE == TWO;
-   |     ^^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(ONE + ONE - TWO).abs() < error`
+   |     ^^^^^^^^^^^^^^^^ help: consider comparing them within some margin of error: `(ONE + ONE - TWO).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:25:5
    |
 LL |     x as f32 == ONE;
-   |     ^^^^^^^^^^^^^^^ help: consider comparing them within some error: `(x as f32 - ONE).abs() < error`
+   |     ^^^^^^^^^^^^^^^ help: consider comparing them within some margin of error: `(x as f32 - ONE).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:28:5
    |
 LL |     v == ONE;
-   |     ^^^^^^^^ help: consider comparing them within some error: `(v - ONE).abs() < error`
+   |     ^^^^^^^^ help: consider comparing them within some margin of error: `(v - ONE).abs() < error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant
   --> $DIR/float_cmp_const.rs:29:5
    |
 LL |     v != ONE;
-   |     ^^^^^^^^ help: consider comparing them within some error: `(v - ONE).abs() > error`
+   |     ^^^^^^^^ help: consider comparing them within some margin of error: `(v - ONE).abs() > error_margin`
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: strict comparison of `f32` or `f64` constant arrays
   --> $DIR/float_cmp_const.rs:61:5
@@ -61,7 +61,7 @@ error: strict comparison of `f32` or `f64` constant arrays
 LL |     NON_ZERO_ARRAY == NON_ZERO_ARRAY2;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error`
+   = note: `f32::EPSILON` and `f64::EPSILON` are available for the `error_margin`
 
 error: aborting due to 8 previous errors