Fix `Item4` is missing in some `ValueTuple`s' `IStructuralEquatable.Equals` (#91461)

* Add missing comparisons

* Add unit tests

src/libraries/System.Private.CoreLib/src/System/ValueTuple.cs

@@ -1125,6 +1125,7 @@ public bool Equals(ValueTuple<T1, T2, T3, T4, T5> other)
             comparer.Equals(Item1, vt.Item1) &&
             comparer.Equals(Item2, vt.Item2) &&
             comparer.Equals(Item3, vt.Item3) &&
+            comparer.Equals(Item4, vt.Item4) &&
             comparer.Equals(Item5, vt.Item5);
 
         int IComparable.CompareTo(object? other)
@@ -1366,6 +1367,7 @@ public bool Equals(ValueTuple<T1, T2, T3, T4, T5, T6> other)
             comparer.Equals(Item1, vt.Item1) &&
             comparer.Equals(Item2, vt.Item2) &&
             comparer.Equals(Item3, vt.Item3) &&
+            comparer.Equals(Item4, vt.Item4) &&
             comparer.Equals(Item5, vt.Item5) &&
             comparer.Equals(Item6, vt.Item6);
 
@@ -1625,6 +1627,7 @@ public bool Equals(ValueTuple<T1, T2, T3, T4, T5, T6, T7> other)
             comparer.Equals(Item1, vt.Item1) &&
             comparer.Equals(Item2, vt.Item2) &&
             comparer.Equals(Item3, vt.Item3) &&
+            comparer.Equals(Item4, vt.Item4) &&
             comparer.Equals(Item5, vt.Item5) &&
             comparer.Equals(Item6, vt.Item6) &&
             comparer.Equals(Item7, vt.Item7);
@@ -1908,6 +1911,7 @@ public bool Equals(ValueTuple<T1, T2, T3, T4, T5, T6, T7, TRest> other)
             comparer.Equals(Item1, vt.Item1) &&
             comparer.Equals(Item2, vt.Item2) &&
             comparer.Equals(Item3, vt.Item3) &&
+            comparer.Equals(Item4, vt.Item4) &&
             comparer.Equals(Item5, vt.Item5) &&
             comparer.Equals(Item6, vt.Item6) &&
             comparer.Equals(Item7, vt.Item7) &&

src/libraries/System.ValueTuple/tests/ValueTupleTests.cs

@@ -799,6 +799,12 @@ public static void OneTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1).Equals(ValueTuple.Create(1)));
+            Assert.False(ValueTuple.Create(1).Equals(ValueTuple.Create(0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1)).Equals(ValueTuple.Create(1), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1)).Equals(ValueTuple.Create(0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1)).ToString());
 
             var vtWithNull = new ValueTuple<string>(null);
@@ -831,6 +837,14 @@ public static void TwoTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1, 2).Equals(ValueTuple.Create(1, 2)));
+            Assert.False(ValueTuple.Create(1, 2).Equals(ValueTuple.Create(0, 2)));
+            Assert.False(ValueTuple.Create(1, 2).Equals(ValueTuple.Create(1, 0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1, 2)).Equals(ValueTuple.Create(1, 2), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2)).Equals(ValueTuple.Create(0, 2), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2)).Equals(ValueTuple.Create(1, 0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1, 2)).ToString());
 
             var vtWithNull = new ValueTuple<string, string>(null, null);
@@ -866,6 +880,16 @@ public static void ThreeTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1, 2, 3).Equals(ValueTuple.Create(1, 2, 3)));
+            Assert.False(ValueTuple.Create(1, 2, 3).Equals(ValueTuple.Create(0, 2, 3)));
+            Assert.False(ValueTuple.Create(1, 2, 3).Equals(ValueTuple.Create(1, 0, 3)));
+            Assert.False(ValueTuple.Create(1, 2, 3).Equals(ValueTuple.Create(1, 2, 0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1, 2, 3)).Equals(ValueTuple.Create(1, 2, 3), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3)).Equals(ValueTuple.Create(0, 2, 3), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3)).Equals(ValueTuple.Create(1, 0, 3), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3)).Equals(ValueTuple.Create(1, 2, 0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2, 3)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1, 2, 3)).ToString());
 
             var vtWithNull = new ValueTuple<string, string, string>(null, null, null);
@@ -905,6 +929,18 @@ public static void FourTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1, 2, 3, 4).Equals(ValueTuple.Create(1, 2, 3, 4)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4).Equals(ValueTuple.Create(0, 2, 3, 4)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4).Equals(ValueTuple.Create(1, 0, 3, 4)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4).Equals(ValueTuple.Create(1, 2, 0, 4)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4).Equals(ValueTuple.Create(1, 2, 3, 0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4)).Equals(ValueTuple.Create(1, 2, 3, 4), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4)).Equals(ValueTuple.Create(0, 2, 3, 4), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4)).Equals(ValueTuple.Create(1, 0, 3, 4), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4)).Equals(ValueTuple.Create(1, 2, 0, 4), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4)).Equals(ValueTuple.Create(1, 2, 3, 0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1, 2, 3, 4)).ToString());
 
             var vtWithNull = new ValueTuple<string, string, string, string>(null, null, null, null);
@@ -947,6 +983,20 @@ public static void FiveTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1, 2, 3, 4, 5).Equals(ValueTuple.Create(1, 2, 3, 4, 5)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5).Equals(ValueTuple.Create(0, 2, 3, 4, 5)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5).Equals(ValueTuple.Create(1, 0, 3, 4, 5)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5).Equals(ValueTuple.Create(1, 2, 0, 4, 5)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5).Equals(ValueTuple.Create(1, 2, 3, 0, 5)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5).Equals(ValueTuple.Create(1, 2, 3, 4, 0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5)).Equals(ValueTuple.Create(1, 2, 3, 4, 5), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5)).Equals(ValueTuple.Create(0, 2, 3, 4, 5), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5)).Equals(ValueTuple.Create(1, 0, 3, 4, 5), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5)).Equals(ValueTuple.Create(1, 2, 0, 4, 5), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5)).Equals(ValueTuple.Create(1, 2, 3, 0, 5), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5)).Equals(ValueTuple.Create(1, 2, 3, 4, 0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1, 2, 3, 4, 5)).ToString());
 
             var vtWithNull = new ValueTuple<string, string, string, string, string>(null, null, null, null, null);
@@ -992,6 +1042,22 @@ public static void SixTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 6)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(0, 2, 3, 4, 5, 6)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(1, 0, 3, 4, 5, 6)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(1, 2, 0, 4, 5, 6)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(1, 2, 3, 0, 5, 6)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(1, 2, 3, 4, 0, 6)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 6), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(0, 2, 3, 4, 5, 6), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(1, 0, 3, 4, 5, 6), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(1, 2, 0, 4, 5, 6), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(1, 2, 3, 0, 5, 6), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(1, 2, 3, 4, 0, 6), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6)).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1, 2, 3, 4, 5, 6)).ToString());
 
             var vtWithNull = new ValueTuple<string, string, string, string, string, string>(null, null, null, null, null, null);
@@ -1040,6 +1106,24 @@ public static void SevenTuples()
 
             Assert.False(((IStructuralEquatable)sc).Equals(sc, DummyTestEqualityComparer.Instance));
 
+            Assert.True(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(0, 2, 3, 4, 5, 6, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 0, 3, 4, 5, 6, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 2, 0, 4, 5, 6, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 2, 3, 0, 5, 6, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 2, 3, 4, 0, 6, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 0, 7)));
+            Assert.False(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 6, 0)));
+
+            Assert.True(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 6, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(0, 2, 3, 4, 5, 6, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 0, 3, 4, 5, 6, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 2, 0, 4, 5, 6, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 2, 3, 0, 5, 6, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 2, 3, 4, 0, 6, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 0, 7), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).Equals(ValueTuple.Create(1, 2, 3, 4, 5, 6, 0), TestEqualityComparer.Instance));
+
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7)", CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(1, 2, 3, 4, 5, 6, 7)).ToString());
 
             var vtWithNull = new ValueTuple<string, string, string, string, string, string, string>(null, null, null, null, null, null, null);
@@ -1109,6 +1193,26 @@ public static void EightTuples()
 
             Assert.False(se.Equals(t, DummyTestEqualityComparer.Instance));
 
+            Assert.True(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(0, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 0, 3, 4, 5, 6, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 0, 4, 5, 6, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 3, 0, 5, 6, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 3, 4, 0, 6, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 3, 4, 5, 0, 7, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 3, 4, 5, 6, 0, ValueTuple.Create(8))));
+            Assert.False(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)).Equals(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(0))));
+
+            Assert.True(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(0, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 0, 3, 4, 5, 6, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 0, 4, 5, 6, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 3, 0, 5, 6, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 3, 4, 0, 6, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 3, 4, 5, 0, 7, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 3, 4, 5, 6, 0, ValueTuple.Create(8)), TestEqualityComparer.Instance));
+            Assert.False(((IStructuralEquatable)CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(8))).Equals(CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create(0)), TestEqualityComparer.Instance));
+
             // Notice that 0-tuple prints as empty position
             Assert.Equal("(1, 2, 3, 4, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, )", CreateLong(1, 2, 3, 4, 5, 6, 7, CreateLong(1, 2, 3, 4, 5, 6, 7, ValueTuple.Create())).ToString());