throw for invalid usage of IgnoreMember (#521)

Author: SimonCropp

docs/serializer-settings.md

@@ -613,7 +613,7 @@ public Task ScopedSerializerFluent()
         .AddExtraSettings(_ => _.TypeNameHandling = TypeNameHandling.All);
 }
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2233-L2260' title='Snippet source file'>snippet source</a> | <a href='#snippet-scopedserializer' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2248-L2275' title='Snippet source file'>snippet source</a> | <a href='#snippet-scopedserializer' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Result:
@@ -881,7 +881,7 @@ public Task WithObsoleteProp()
     return Verify(target);
 }
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2197-L2217' title='Snippet source file'>snippet source</a> | <a href='#snippet-withobsoleteprop' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2212-L2232' title='Snippet source file'>snippet source</a> | <a href='#snippet-withobsoleteprop' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Result:
@@ -929,7 +929,7 @@ public Task WithObsoletePropIncludedFluent()
         .IncludeObsoletes();
 }
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2168-L2195' title='Snippet source file'>snippet source</a> | <a href='#snippet-withobsoletepropincluded' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2183-L2210' title='Snippet source file'>snippet source</a> | <a href='#snippet-withobsoletepropincluded' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Or globally:
@@ -939,7 +939,7 @@ Or globally:
 ```cs
 VerifierSettings.IncludeObsoletes();
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2161-L2165' title='Snippet source file'>snippet source</a> | <a href='#snippet-withobsoletepropincludedglobally' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2176-L2180' title='Snippet source file'>snippet source</a> | <a href='#snippet-withobsoletepropincludedglobally' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Result:
@@ -1169,7 +1169,7 @@ public Task CustomExceptionPropFluent()
         .IgnoreMembersThatThrow<CustomException>();
 }
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2057-L2076' title='Snippet source file'>snippet source</a> | <a href='#snippet-ignoremembersthatthrow' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2072-L2091' title='Snippet source file'>snippet source</a> | <a href='#snippet-ignoremembersthatthrow' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Or globally:
@@ -1179,7 +1179,7 @@ Or globally:
 ```cs
 VerifierSettings.IgnoreMembersThatThrow<CustomException>();
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2050-L2054' title='Snippet source file'>snippet source</a> | <a href='#snippet-ignoremembersthatthrowglobal' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L2065-L2069' title='Snippet source file'>snippet source</a> | <a href='#snippet-ignoremembersthatthrowglobal' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Result:

readme.md

@@ -309,7 +309,7 @@ public Task VerifyJsonJToken()
     return VerifyJson(target);
 }
 ```
-<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L1981-L2013' title='Snippet source file'>snippet source</a> | <a href='#snippet-verifyjson' title='Start of snippet'>anchor</a></sup>
+<sup><a href='/src/Verify.Tests/Serialization/SerializationTests.cs#L1996-L2028' title='Snippet source file'>snippet source</a> | <a href='#snippet-verifyjson' title='Start of snippet'>anchor</a></sup>
 <!-- endSnippet -->
 
 Results in:

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;CS0649;xUnit1026;xUnit1013;msb3277;CS0436</NoWarn>
-    <Version>16.8.0</Version>
+    <Version>16.8.1</Version>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>10</LangVersion>
     <SuppressTfmSupportBuildWarnings>true</SuppressTfmSupportBuildWarnings>

src/Verify.Tests/Serialization/SerializationTests.IgnoreMemberSubClass.verified.txt

@@ -0,0 +1,6 @@
+{
+  Type: Exception,
+  Message:
+IgnoreMember<T> can only be used on the type that defines the member.
+To ignore specific members for T, create a custom converter.
+}

src/Verify.Tests/Serialization/SerializationTests.cs

@@ -1919,6 +1919,21 @@ public Task IgnoreMemberByNameFluent()
 
     #endregion
 
+    public class IgnoreTargetBase
+    {
+        public string Property { get; set; }
+    }
+
+    public class IgnoreTargetSub :
+        IgnoreTargetBase
+    {
+    }
+
+    [Fact]
+    public Task IgnoreMemberSubClass() =>
+        Throws(() => VerifierSettings.IgnoreMember<IgnoreTargetSub>(_ => _.Property))
+            .IgnoreStackTrack();
+
     [Fact]
     public Task IgnoreJTokenByName()
     {

src/Verify/Serialization/SerializationSettings_Ignore.cs

@@ -21,7 +21,14 @@ public void IgnoreMember<T>(Expression<Func<T, object?>> expression)
         where T : notnull
     {
         var member = expression.FindMember();
-        IgnoreMember(member.DeclaringType!, member.Name);
+        var declaringType = member.DeclaringType!;
+        if (typeof(T) != declaringType)
+        {
+            throw new(@"IgnoreMember<T> can only be used on the type that defines the member.
+To ignore specific members for T, create a custom converter.");
+        }
+
+        IgnoreMember(declaringType, member.Name);
     }
 
     public void IgnoreMembers<T>(params string[] names)