Keep a node's codomain when a rewrite rebuilds it (#955)

BREAKING-CHANGES.md

@@ -25,6 +25,25 @@ read first.
 | **Silent** | `"1/x".Integrate("x")`, and every antiderivative with a logarithm | `ln(abs(x)) + C` | `ln(x) + C` |
 | **Silent** | `CostModel.FewestDivisions.Cost(y ^ (1 * (-1)) * x)` | `0.007`, cheaper than `x / y` | `1.007` |
 | **Silent** | `Real.NaN > (Real)1`, and the other three operators | `true` | `false` |
+| **Silent** | a rewritten expression under `domain(...)` — including via `Substitute` | the constraint was dropped, so it answered | it refuses, as it did before the rewrite |
+
+### A rewritten node keeps its `Codomain`, so a domain constraint no longer disappears
+
+`Entity.Replace` rebuilds every node on the path to a change, and a rebuilt node started from its
+type's default codomain rather than the one the original carried. Any rewrite therefore dropped a
+`domain(...)` annotation — including `Substitute`, which is built on `Replace`.
+
+```csharp
+"domain(sqrt(x), ZZ)".ToEntity().Substitute("x", "4/9".ToEntity()).EvalNumerical()
+// was: 2/3     now: NaN        — 2/3 is not an integer, so the constraint refuses it
+```
+
+The old behaviour was **silent** and one-sided: constraints were only ever weakened, never
+strengthened, so a rewrite could make an undefined expression look defined but never the reverse.
+An expression that answered a value where it should have refused now refuses.
+
+Measured: the whole suite passes unchanged with the fix in, so nothing in the library depended on
+the annotation being lost. [#955](https://github.com/asc-community/AngouriMath/issues/955).
 
 ### `Real`'s comparison operators refuse `NaN` instead of ordering it
 

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.AbsSignum.Classes.cs

@@ -20,7 +20,7 @@ public sealed partial record Signumf(Entity Argument) : Function, IUnaryNode
             public Entity NodeChild => Argument;
 
             private Signumf New(Entity arg) =>
-                ReferenceEquals(Argument, arg) ? this : new(arg);
+                ReferenceEquals(Argument, arg) ? this : new(arg) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -36,7 +36,7 @@ public sealed partial record Absf(Entity Argument) : Function, IUnaryNode
             public Entity NodeChild => Argument;
 
             private Absf New(Entity arg) =>
-                ReferenceEquals(Argument, arg) ? this : new(arg);
+                ReferenceEquals(Argument, arg) ? this : new(arg) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.ArcTrigonometry.Classes.cs

@@ -20,7 +20,7 @@ public sealed partial record Arcsinf(Entity Argument) : TrigonometricFunction, I
             public Entity NodeChild => Argument;
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            private Arcsinf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            private Arcsinf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -36,7 +36,7 @@ public sealed partial record Arccosf(Entity Argument) : TrigonometricFunction, I
             public Entity NodeChild => Argument;
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            private Arccosf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            private Arccosf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -52,7 +52,7 @@ public sealed partial record Arctanf(Entity Argument) : TrigonometricFunction, I
             public Entity NodeChild => Argument;
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            private Arctanf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            private Arctanf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -68,7 +68,7 @@ public sealed partial record Arccotanf(Entity Argument) : TrigonometricFunction,
             public Entity NodeChild => Argument;
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            Arccotanf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            Arccotanf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -84,7 +84,7 @@ public sealed partial record Arcsecantf(Entity Argument) : TrigonometricFunction
             public Entity NodeChild => Argument;
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            private Arcsecantf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            private Arcsecantf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -100,7 +100,7 @@ public sealed partial record Arccosecantf(Entity Argument) : TrigonometricFuncti
             public Entity NodeChild => Argument;
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            private Arccosecantf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            private Arccosecantf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Calculus.Classes.cs

@@ -22,7 +22,7 @@ public sealed partial record Derivativef(Entity Expression, Entity Var, int Iter
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Derivativef New(Entity expression, Entity var) =>
                 ReferenceEquals(Expression, expression) && ReferenceEquals(Var, var)
-                ? this : new(expression, var, Iterations);
+                ? this : new(expression, var, Iterations) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) =>
                 func(New(Expression.Replace(func), Var.Replace(func)));
@@ -40,7 +40,7 @@ private Integralf New(Entity expression, Entity var, (Entity from, Entity to)? r
                 ReferenceEquals(Expression, expression) && ReferenceEquals(Var, var)
                 && (range is null && Range is null || range is var (newFrom, newTo) && Range is var (oldFrom, oldTo)
                     && ReferenceEquals(newFrom, oldFrom) && ReferenceEquals(newTo, oldTo))
-                ? this : new(expression, var, range);
+                ? this : new(expression, var, range) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) =>
                 func(New(Expression.Replace(func), Var, Range is var (from, to) ? (from.Replace(func), to.Replace(func)) : null));
@@ -56,7 +56,7 @@ public sealed partial record Limitf(Entity Expression, Entity Var, Entity Destin
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Limitf New(Entity expression, Entity var, Entity destination, ApproachFrom approachFrom) =>
                 ReferenceEquals(Expression, expression) && ReferenceEquals(Var, var) && ReferenceEquals(Destination, destination)
-                && ApproachFrom == approachFrom ? this : new(expression, var, destination, approachFrom);
+                && ApproachFrom == approachFrom ? this : new(expression, var, destination, approachFrom) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) =>
                 func(New(Expression.Replace(func), Var.Replace(func), Destination.Replace(func), ApproachFrom));

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Exponential.Classes.cs

@@ -18,7 +18,7 @@ public sealed partial record Powf(Entity Base, Entity Exponent) : Function, IBin
         {
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Powf New(Entity @base, Entity exponent) =>
-                ReferenceEquals(Base, @base) && ReferenceEquals(Exponent, exponent) ? this : new(@base, exponent);
+                ReferenceEquals(Base, @base) && ReferenceEquals(Exponent, exponent) ? this : new(@base, exponent) { Codomain = Codomain };
             internal override Priority Priority => Priority.Pow;
 
             /// <inheritdoc/>
@@ -40,7 +40,7 @@ public sealed partial record Logf(Entity Base, Entity Antilogarithm) : Function,
         {
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Logf New(Entity @base, Entity antilogarithm) =>
-                ReferenceEquals(Base, @base) && ReferenceEquals(Antilogarithm, antilogarithm) ? this : new(@base, antilogarithm);
+                ReferenceEquals(Base, @base) && ReferenceEquals(Antilogarithm, antilogarithm) ? this : new(@base, antilogarithm) { Codomain = Codomain };
 
             /// <inheritdoc/>
             public Entity NodeFirstChild => Base;

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Factorial.Classes.cs

@@ -17,7 +17,7 @@ partial record Entity
         public sealed partial record Factorialf(Entity Argument) : Function, IUnaryNode
         {
             /// <summary>Reuse the cache by returning the same object if possible</summary>
-            private Factorialf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument);
+            private Factorialf New(Entity argument) => ReferenceEquals(Argument, argument) ? this : new(argument) { Codomain = Codomain };
             // This is still a function for pattern replacement
             internal override Priority Priority => Priority.Factorial;
 

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Floors.Classes.cs

@@ -1,4 +1,4 @@
-//
+//
 // Copyright (c) 2019-2026 Angouri.
 // AngouriMath is licensed under MIT.
 // Details: https://github.com/asc-community/AngouriMath/blob/master/LICENSE.md.
@@ -26,7 +26,7 @@ public sealed partial record Floorf(Entity Argument) : Function, IUnaryNode
             public Entity NodeChild => Argument;
 
             private Floorf New(Entity arg) =>
-                ReferenceEquals(Argument, arg) ? this : new(arg);
+                ReferenceEquals(Argument, arg) ? this : new(arg) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -46,7 +46,7 @@ public sealed partial record Ceilf(Entity Argument) : Function, IUnaryNode
             public Entity NodeChild => Argument;
 
             private Ceilf New(Entity arg) =>
-                ReferenceEquals(Argument, arg) ? this : new(arg);
+                ReferenceEquals(Argument, arg) ? this : new(arg) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Operators.Classes.cs

@@ -30,7 +30,7 @@ public static Entity Sum(IEnumerable<Entity> terms)
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Sumf New(Entity augend, Entity addend) =>
-                ReferenceEquals(Augend, augend) && ReferenceEquals(Addend, addend) ? this : new(augend, addend);
+                ReferenceEquals(Augend, augend) && ReferenceEquals(Addend, addend) ? this : new(augend, addend) { Codomain = Codomain };
             internal override Priority Priority => Priority.Sum;
 
             /// <inheritdoc/>
@@ -65,7 +65,7 @@ public sealed partial record Minusf(Entity Minuend, Entity Subtrahend) : Continu
         {
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Minusf New(Entity minuend, Entity subtrahend) =>
-                ReferenceEquals(Minuend, minuend) && ReferenceEquals(Subtrahend, subtrahend) ? this : new(minuend, subtrahend);
+                ReferenceEquals(Minuend, minuend) && ReferenceEquals(Subtrahend, subtrahend) ? this : new(minuend, subtrahend) { Codomain = Codomain };
             internal override Priority Priority => Priority.Minus;
 
             /// <inheritdoc/>
@@ -99,7 +99,7 @@ public static Entity Multiply(IEnumerable<Entity> terms)
 
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             private Mulf New(Entity multiplier, Entity multiplicand) =>
-                ReferenceEquals(Multiplier, multiplier) && ReferenceEquals(Multiplicand, multiplicand) ? this : new(multiplier, multiplicand);
+                ReferenceEquals(Multiplier, multiplier) && ReferenceEquals(Multiplicand, multiplicand) ? this : new(multiplier, multiplicand) { Codomain = Codomain };
             internal override Priority Priority => Priority.Mul;
 
             /// <inheritdoc/>
@@ -134,7 +134,7 @@ public sealed partial record Divf(Entity Dividend, Entity Divisor) : ContinuousN
         {
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             internal Divf New(Entity dividend, Entity divisor) =>
-                ReferenceEquals(Dividend, dividend) && ReferenceEquals(Divisor, divisor) ? this : new(dividend, divisor);
+                ReferenceEquals(Dividend, dividend) && ReferenceEquals(Divisor, divisor) ? this : new(dividend, divisor) { Codomain = Codomain };
             internal override Priority Priority => Priority.Div;
 
             /// <inheritdoc/>
@@ -159,7 +159,7 @@ public sealed partial record Modf(Entity Dividend, Entity Divisor) : ContinuousN
         {
             /// <summary>Reuse the cache by returning the same object if possible</summary>
             internal Modf New(Entity dividend, Entity divisor) =>
-                ReferenceEquals(Dividend, dividend) && ReferenceEquals(Divisor, divisor) ? this : new(dividend, divisor);
+                ReferenceEquals(Dividend, dividend) && ReferenceEquals(Divisor, divisor) ? this : new(dividend, divisor) { Codomain = Codomain };
             internal override Priority Priority => Priority.Mul;
 
             /// <inheritdoc/>

Sources/AngouriMath/Core/Entity/Continuous/Entity.Continuous.Rounding.Classes.cs

@@ -1,4 +1,4 @@
-//
+//
 // Copyright (c) 2019-2026 Angouri.
 // AngouriMath is licensed under MIT.
 // Details: https://github.com/asc-community/AngouriMath/blob/master/LICENSE.md.
@@ -26,7 +26,7 @@ public sealed partial record Roundf(Entity Argument) : Function, IUnaryNode
             public Entity NodeChild => Argument;
 
             private Roundf New(Entity arg) =>
-                ReferenceEquals(Argument, arg) ? this : new(arg);
+                ReferenceEquals(Argument, arg) ? this : new(arg) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Argument.Replace(func)));
             /// <inheritdoc/>
@@ -53,7 +53,7 @@ public sealed partial record Minf(Entity Left, Entity Right) : Function, IBinary
             public Entity NodeSecondChild => Right;
 
             private Minf New(Entity left, Entity right) =>
-                ReferenceEquals(Left, left) && ReferenceEquals(Right, right) ? this : new(left, right);
+                ReferenceEquals(Left, left) && ReferenceEquals(Right, right) ? this : new(left, right) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Left.Replace(func), Right.Replace(func)));
             /// <inheritdoc/>
@@ -73,7 +73,7 @@ public sealed partial record Maxf(Entity Left, Entity Right) : Function, IBinary
             public Entity NodeSecondChild => Right;
 
             private Maxf New(Entity left, Entity right) =>
-                ReferenceEquals(Left, left) && ReferenceEquals(Right, right) ? this : new(left, right);
+                ReferenceEquals(Left, left) && ReferenceEquals(Right, right) ? this : new(left, right) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Left.Replace(func), Right.Replace(func)));
             /// <inheritdoc/>
@@ -99,7 +99,7 @@ public sealed partial record Gcdf(Entity Left, Entity Right) : Function, IBinary
             public Entity NodeSecondChild => Right;
 
             private Gcdf New(Entity left, Entity right) =>
-                ReferenceEquals(Left, left) && ReferenceEquals(Right, right) ? this : new(left, right);
+                ReferenceEquals(Left, left) && ReferenceEquals(Right, right) ? this : new(left, right) { Codomain = Codomain };
             /// <inheritdoc/>
             public override Entity Replace(Func<Entity, Entity> func) => func(New(Left.Replace(func), Right.Replace(func)));
             /// <inheritdoc/>