Improve error messages for accidental Equals usage

Src/FluentAssertions/Collections/GenericCollectionAssertions.cs

@@ -35,6 +35,8 @@ public GenericCollectionAssertions(TCollection actualValue)
     }
 }
 
+#pragma warning disable CS0659 // Ignore not overriding Object.GetHashCode()
+#pragma warning disable CA1065 // Ignore throwing NotSupportedException from Equals
 [DebuggerNonUserCode]
 public class GenericCollectionAssertions<TCollection, T, TAssertions> :
     ReferenceTypeAssertions<TCollection, TAssertions>
@@ -3449,6 +3451,10 @@ private AndConstraint<TAssertions> NotBeInOrder(IComparer<T> comparer, SortOrder
         return new AndConstraint<TAssertions>((TAssertions)this);
     }
 
+    /// <inheritdoc/>
+    public override bool Equals(object obj) =>
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean BeSameAs() or Equal() instead?");
+
     private static int IndexOf(IList<T> items, T item, int startIndex)
     {
         Func<T, T, bool> comparer = ObjectExtensions.GetComparer<T>();

Src/FluentAssertions/Numeric/NumericAssertions.cs

@@ -474,7 +474,7 @@ public AndConstraint<TAssertions> NotBeOfType(Type unexpectedType, string becaus
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 
     private protected virtual bool IsNaN(T value) => false;
 

Src/FluentAssertions/Primitives/BooleanAssertions.cs

@@ -120,5 +120,5 @@ public AndConstraint<TAssertions> NotBe(bool unexpected, string because = "", pa
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/DateOnlyAssertions.cs

@@ -512,7 +512,7 @@ public AndConstraint<TAssertions> BeOneOf(IEnumerable<DateOnly?> validValues, st
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }
 
 #endif

Src/FluentAssertions/Primitives/DateTimeAssertions.cs

@@ -925,5 +925,5 @@ public AndConstraint<TAssertions> BeIn(DateTimeKind expectedKind, string because
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/DateTimeOffsetAssertions.cs

@@ -1094,5 +1094,5 @@ public AndConstraint<TAssertions> BeOneOf(IEnumerable<DateTimeOffset?> validValu
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/DateTimeOffsetRangeAssertions.cs

@@ -132,5 +132,5 @@ private static string PositionRelativeToTarget(DateTimeOffset actual, DateTimeOf
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Before() or After() instead?");
 }

Src/FluentAssertions/Primitives/DateTimeRangeAssertions.cs

@@ -135,5 +135,5 @@ private static string PositionRelativeToTarget(DateTime actual, DateTime target)
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Before() or After() instead?");
 }

Src/FluentAssertions/Primitives/EnumAssertions.cs

@@ -443,5 +443,5 @@ private static string GetName<T>(T @enum)
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/GuidAssertions.cs

@@ -171,5 +171,5 @@ public AndConstraint<TAssertions> NotBe(Guid unexpected, string because = "", pa
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/ObjectAssertions.cs

@@ -17,6 +17,8 @@ public ObjectAssertions(object value)
     }
 }
 
+#pragma warning disable CS0659 // Ignore not overriding Object.GetHashCode()
+#pragma warning disable CA1065 // Ignore throwing NotSupportedException from Equals
 /// <summary>
 /// Contains a number of methods to assert that a <typeparamref name="TSubject"/> is in the expected state.
 /// </summary>
@@ -220,6 +222,10 @@ public AndConstraint<TAssertions> NotBe(TSubject unexpected, string because = ""
         return new AndConstraint<TAssertions>((TAssertions)this);
     }
 
+    /// <inheritdoc/>
+    public override bool Equals(object obj) =>
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() or BeSameAs() instead?");
+
     /// <summary>
     /// Returns the type of the subject the assertion applies on.
     /// </summary>

Src/FluentAssertions/Primitives/ReferenceTypeAssertions.cs

@@ -422,5 +422,5 @@ public AndConstraint<TAssertions> NotBeAssignableTo(Type type, string because =
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/SimpleTimeSpanAssertions.cs

@@ -301,5 +301,5 @@ public AndConstraint<TAssertions> BeGreaterThan(TimeSpan expected, string becaus
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Primitives/TimeOnlyAssertions.cs

@@ -566,7 +566,7 @@ public AndConstraint<TAssertions> BeOneOf(IEnumerable<TimeOnly?> validValues, st
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }
 
 #endif

Src/FluentAssertions/Specialized/ExecutionTimeAssertions.cs

@@ -231,5 +231,5 @@ public AndConstraint<ExecutionTimeAssertions> BeCloseTo(TimeSpan expectedDuratio
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean BeLessThanOrEqualTo() or BeGreaterThanOrEqualTo() instead?");
 }

Src/FluentAssertions/Specialized/TaskCompletionSourceAssertions.cs

@@ -184,7 +184,7 @@ protected TaskCompletionSourceAssertionsBase(IClock clock)
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean CompleteWithinAsync() instead?");
 
     /// <summary>
     ///     Monitors the specified task whether it completes withing the remaining time span.

Src/FluentAssertions/Types/MethodInfoSelectorAssertions.cs

@@ -330,5 +330,5 @@ private static string GetDescriptionsFor(IEnumerable<MethodInfo> methods)
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Types/PropertyInfoSelectorAssertions.cs

@@ -229,5 +229,5 @@ private static string GetDescriptionsFor(IEnumerable<PropertyInfo> properties)
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Src/FluentAssertions/Types/TypeSelectorAssertions.cs

@@ -477,5 +477,5 @@ private static string GetDescriptionFor(Type type)
 
     /// <inheritdoc/>
     public override bool Equals(object obj) =>
-        throw new NotSupportedException("Calling Equals on Assertion classes is not supported.");
+        throw new NotSupportedException("Equals is not part of Fluent Assertions. Did you mean Be() instead?");
 }

Tests/Approval.Tests/ApprovedApi/FluentAssertions/net47.verified.txt

@@ -463,6 +463,7 @@ namespace FluentAssertions.Collections
         public FluentAssertions.AndConstraint<TAssertions> Equal(params T[] elements) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal(System.Collections.Generic.IEnumerable<T> expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal<TExpectation>(System.Collections.Generic.IEnumerable<TExpectation> expectation, System.Func<T, TExpectation, bool> equalityComparison, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(int expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(System.Linq.Expressions.Expression<System.Func<int, bool>> countPredicate, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCountGreaterOrEqualTo(int expected, string because = "", params object[] becauseArgs) { }
@@ -2100,6 +2101,7 @@ namespace FluentAssertions.Primitives
         public FluentAssertions.AndConstraint<TAssertions> Be(TSubject expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBe(TSubject unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }

Tests/Approval.Tests/ApprovedApi/FluentAssertions/net6.0.verified.txt

@@ -476,6 +476,7 @@ namespace FluentAssertions.Collections
         public FluentAssertions.AndConstraint<TAssertions> Equal(params T[] elements) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal(System.Collections.Generic.IEnumerable<T> expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal<TExpectation>(System.Collections.Generic.IEnumerable<TExpectation> expectation, System.Func<T, TExpectation, bool> equalityComparison, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(int expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(System.Linq.Expressions.Expression<System.Func<int, bool>> countPredicate, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCountGreaterOrEqualTo(int expected, string because = "", params object[] becauseArgs) { }
@@ -2184,6 +2185,7 @@ namespace FluentAssertions.Primitives
         public FluentAssertions.AndConstraint<TAssertions> Be(TSubject expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBe(TSubject unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }

Tests/Approval.Tests/ApprovedApi/FluentAssertions/netcoreapp2.1.verified.txt

@@ -463,6 +463,7 @@ namespace FluentAssertions.Collections
         public FluentAssertions.AndConstraint<TAssertions> Equal(params T[] elements) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal(System.Collections.Generic.IEnumerable<T> expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal<TExpectation>(System.Collections.Generic.IEnumerable<TExpectation> expectation, System.Func<T, TExpectation, bool> equalityComparison, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(int expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(System.Linq.Expressions.Expression<System.Func<int, bool>> countPredicate, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCountGreaterOrEqualTo(int expected, string because = "", params object[] becauseArgs) { }
@@ -2100,6 +2101,7 @@ namespace FluentAssertions.Primitives
         public FluentAssertions.AndConstraint<TAssertions> Be(TSubject expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBe(TSubject unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }

Tests/Approval.Tests/ApprovedApi/FluentAssertions/netcoreapp3.0.verified.txt

@@ -463,6 +463,7 @@ namespace FluentAssertions.Collections
         public FluentAssertions.AndConstraint<TAssertions> Equal(params T[] elements) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal(System.Collections.Generic.IEnumerable<T> expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> Equal<TExpectation>(System.Collections.Generic.IEnumerable<TExpectation> expectation, System.Func<T, TExpectation, bool> equalityComparison, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(int expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCount(System.Linq.Expressions.Expression<System.Func<int, bool>> countPredicate, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> HaveCountGreaterOrEqualTo(int expected, string because = "", params object[] becauseArgs) { }
@@ -2100,6 +2101,7 @@ namespace FluentAssertions.Primitives
         public FluentAssertions.AndConstraint<TAssertions> Be(TSubject expected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> BeEquivalentTo<TExpectation>(TExpectation expectation, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }
+        public override bool Equals(object obj) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBe(TSubject unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, string because = "", params object[] becauseArgs) { }
         public FluentAssertions.AndConstraint<TAssertions> NotBeEquivalentTo<TExpectation>(TExpectation unexpected, System.Func<FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>, FluentAssertions.Equivalency.EquivalencyAssertionOptions<TExpectation>> config, string because = "", params object[] becauseArgs) { }