check f16 and f128 in float_equality_without_abs (#15054)

followup of #141874

cc #116909

changelog: check f16 and f128 in float_equality_without_abs

Author: llogiq

clippy_lints/src/operators/float_equality_without_abs.rs

@@ -34,11 +34,11 @@ pub(crate) fn check<'tcx>(
             val_r,
         ) = lhs.kind
 
-        // right hand side matches either f32::EPSILON or f64::EPSILON
+        // right hand side matches _::EPSILON
         && let ExprKind::Path(ref epsilon_path) = rhs.kind
         && let Res::Def(DefKind::AssocConst, def_id) = cx.qpath_res(epsilon_path, rhs.hir_id)
-        && let Some(epsilon) = cx.tcx.get_diagnostic_name(def_id)
-        && matches!(epsilon, sym::f32_epsilon| sym::f64_epsilon)
+        && let Some(sym) = cx.tcx.get_diagnostic_name(def_id)
+        && matches!(sym, sym::f16_epsilon | sym::f32_epsilon | sym::f64_epsilon | sym::f128_epsilon)
 
         // values of the subtractions on the left hand side are of the type float
         && let t_val_l = cx.typeck_results().expr_ty(val_l)

tests/ui/float_equality_without_abs.rs

@@ -1,8 +1,8 @@
+#![feature(f128)]
+#![feature(f16)]
 #![warn(clippy::float_equality_without_abs)]
 //@no-rustfix: suggestions cause type ambiguity
 
-// FIXME(f16_f128): add tests for these types when abs is available
-
 pub fn is_roughly_equal(a: f32, b: f32) -> bool {
     (a - b) < f32::EPSILON
     //~^ float_equality_without_abs
@@ -44,10 +44,20 @@ pub fn main() {
     let _ = f32::EPSILON > 1.0 - 2.0;
     //~^ float_equality_without_abs
 
+    let _ = (a as f16 - b as f16) < f16::EPSILON;
+    //~^ float_equality_without_abs
+
+    let _ = (a as f128 - b as f128) < f128::EPSILON;
+    //~^ float_equality_without_abs
+
     // those are correct
+    let _ = (a as f16 - b as f16).abs() < f16::EPSILON;
     let _ = (a - b).abs() < f32::EPSILON;
     let _ = (a as f64 - b as f64).abs() < f64::EPSILON;
+    let _ = (a as f128 - b as f128).abs() < f128::EPSILON;
 
+    let _ = f16::EPSILON > (a as f16 - b as f16).abs();
     let _ = f32::EPSILON > (a - b).abs();
     let _ = f64::EPSILON > (a as f64 - b as f64).abs();
+    let _ = f128::EPSILON > (a as f128 - b as f128).abs();
 }

tests/ui/float_equality_without_abs.stderr

@@ -89,5 +89,21 @@ LL |     let _ = f32::EPSILON > 1.0 - 2.0;
    |                            |
    |                            help: add `.abs()`: `(1.0 - 2.0).abs()`
 
-error: aborting due to 11 previous errors
+error: float equality check without `.abs()`
+  --> tests/ui/float_equality_without_abs.rs:47:13
+   |
+LL |     let _ = (a as f16 - b as f16) < f16::EPSILON;
+   |             ---------------------^^^^^^^^^^^^^^^
+   |             |
+   |             help: add `.abs()`: `(a as f16 - b as f16).abs()`
+
+error: float equality check without `.abs()`
+  --> tests/ui/float_equality_without_abs.rs:50:13
+   |
+LL |     let _ = (a as f128 - b as f128) < f128::EPSILON;
+   |             -----------------------^^^^^^^^^^^^^^^^
+   |             |
+   |             help: add `.abs()`: `(a as f128 - b as f128).abs()`
+
+error: aborting due to 13 previous errors