A number's conjugate is made under the setting in force

BREAKING-CHANGES.md

@@ -319,6 +319,16 @@ Both are real, `im(3 + 4i)` being `4`, real-linear, and turned by the conjugate
 | `"im(3 + 4i)".ToEntity().Simplify()` | `(3 + 4i) * im` | `4` |
 | `"re * x".ToEntity()` | `re * x` | `re * x` |
 
+### A number's conjugate is made under the setting in force
+
+**Silent: `Complex.Conjugate` is made under the downcasting setting of the caller, where the first caller's setting was
+kept on the number for every caller after it.** A division by `i` with the downcasting off conjugates `i`, and left its
+conjugate as `0 - 1i`, in decimals, on the one instance that every `i` is, in every thread from then on.
+
+| Input | Was (2.6.0) | Now |
+|---|---|---|
+| `Complex.ImaginaryOne.Conjugate`, after `(1 / Complex.ImaginaryOne).Evaled` with `DowncastingEnabled` off | `0 - 1i` | `-i` |
+
 ### `conjugate`, `conj` and `arg` are functions
 
 **Not silent: these names followed by a bracket are now the complex conjugate and the principal argument, where they

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Complex.Definition.cs

@@ -40,8 +40,13 @@ private protected Complex(Real? real, Real? imaginary) =>
                 /// <summary>
                 /// Conjugate of a complex number. Given this = a + ib, Conjugate = a - ib
                 /// </summary>
-                public Complex Conjugate => conjugate.GetValue(static @this => Create(@this.RealPart, -@this.ImaginaryPart), this);
-                private LazyPropertyA<Complex> conjugate;
+                /// <remarks>
+                /// Made under the downcasting setting in force, as any other number is, and so not kept
+                /// on the instance: the first to ask decided it for everyone. A division by <c>i</c> with
+                /// the downcasting off left <c>0 - 1i</c>, in decimals, on <see cref="ImaginaryOne"/>, and
+                /// <c>conj(i)</c> was that from then on, in every thread.
+                /// </remarks>
+                public Complex Conjugate => Create(RealPart, -ImaginaryPart);
 
                 internal override Priority Priority =>
                     (RealPart, ImaginaryPart) switch

Sources/Tests/UnitTests/Core/Numeric.cs

@@ -458,5 +458,20 @@ public void AModulusIsMadeUnderTheDowncastingInForce()
                 Assert.Equal(Integer.Create(325), Complex.Create(EDecimal.FromInt32(75), rootOf100000).Abs());
             }
         }
+
+        /// <summary>
+        /// A conjugate is made under the setting in force, as every other number is. It was kept on
+        /// the instance, so a division by <c>i</c> with the downcasting off left <c>0 - 1i</c>, in
+        /// decimals, as the conjugate of <see cref="Complex.ImaginaryOne"/>, and <c>conj(i)</c> was
+        /// that for every caller after it: two tests failed or passed by the order the suite ran in.
+        /// </summary>
+        [Fact]
+        public void AConjugateIsMadeUnderTheSettingInForce()
+        {
+            using (MathS.Settings.DowncastingEnabled.Set(false))
+                Assert.IsType<Complex>((1 / Complex.ImaginaryOne).Evaled);
+            Assert.Equal(Complex.MinusImaginaryOne, Complex.ImaginaryOne.Conjugate);
+            Assert.Equal(Complex.MinusImaginaryOne, "conj(i)".ToEntity().InnerSimplified);
+        }
     }
 }