Fix check to look at inherited types as well.

src/EditorFeatures/VisualBasicTest/Diagnostics/RemoveUnnecessaryCast/RemoveUnnecessaryCastTests.vb

@@ -1363,7 +1363,7 @@ End Module
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
         <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
-        Public Async Function TestDontRemoveNecessaryPredefinedCastWithGetType() As Task
+        Public Async Function TestDontRemoveNecessaryStringPredefinedCastWithGetType() As Task
             Dim markup =
 <File>
 Module Program
@@ -1378,7 +1378,37 @@ End Module
 
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
         <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
-        Public Async Function TestDontRemoveNecessaryCTypeCastWithGetType() As Task
+        Public Async Function TestDontRemoveNecessaryWideningPredefinedCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|CLng(a).GetType()|]
+    End Sub
+End Module
+</File>
+            Await TestMissingAsync(markup)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestDontRemoveNecessaryNarrowingPredefinedCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|CByte(a).GetType()|]
+    End Sub
+End Module
+</File>
+            Await TestMissingAsync(markup)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestDontRemoveNecessaryStringCTypeCastWithGetType() As Task
             Dim markup =
 <File>
 Module Program
@@ -1391,6 +1421,174 @@ End Module
             Await TestMissingAsync(markup)
         End Function
 
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestDontRemoveNecessaryWideningCTypeCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|CType(a, Long).GetType()|]
+    End Sub
+End Module
+</File>
+            Await TestMissingAsync(markup)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestDontRemoveNecessaryNarrowingCTypeCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|CType(a, Byte).GetType()|]
+    End Sub
+End Module
+</File>
+            Await TestMissingAsync(markup)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestDontRemoveNecessaryUserDefinedCTypeCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|CType(a, WeirdInt).GetType()|]
+    End Sub
+
+    Public Class WeirdInt
+        Private val As Integer
+        Public Sub New(ByVal b As Integer)
+            Me.val = b
+        End Sub
+        Public Shared Widening Operator CType(ByVal d As WeirdInt) As Integer
+            Return d.val
+        End Operator
+        Public Shared Narrowing Operator CType(ByVal i As Integer) As WeirdInt
+            Return New WeirdInt(i)
+        End Operator
+    End Class
+End Module
+</File>
+            Await TestMissingAsync(markup)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestRemoveUnnecessaryCTypeCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|CType(a, Object).GetType()|]
+    End Sub
+End Module
+</File>
+            Dim expected =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = a.GetType()
+    End Sub
+End Module
+</File>
+            Await TestAsync(markup, expected)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestRemoveUnnecessaryInheritedCTypeCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a As BaseClass
+        a = New DerivedClass()
+        Dim b = [|CType(a, BaseClass).GetType()|]
+    End Sub
+
+    Public Class BaseClass
+    End Class
+
+    Public Class DerivedClass : Inherits BaseClass
+    End Class
+End Module
+</File>
+            Dim expected =
+<File>
+Module Program
+    Sub Main()
+        Dim a As BaseClass
+        a = New DerivedClass()
+        Dim b = a.GetType()
+    End Sub
+
+    Public Class BaseClass
+    End Class
+
+    Public Class DerivedClass : Inherits BaseClass
+    End Class
+End Module
+</File>
+            Await TestAsync(markup, expected)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestRemoveUnnecessaryDirectCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|DirectCast(a, Object).GetType()|]
+    End Sub
+End Module
+</File>
+            Dim expected =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = a.GetType()
+    End Sub
+End Module
+</File>
+            Await TestAsync(markup, expected)
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
+        <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
+        Public Async Function TestRemoveUnnecessaryTryCastWithGetType() As Task
+            Dim markup =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = [|TryCast(a, Object).GetType()|]
+    End Sub
+End Module
+</File>
+            Dim expected =
+<File>
+Module Program
+    Sub Main()
+        Dim a = 2
+        Dim b = a.GetType()
+    End Sub
+End Module
+</File>
+            Await TestAsync(markup, expected)
+        End Function
+
         <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryCast)>
         <WorkItem(32399, "https://github.com/dotnet/roslyn/issues/32399")>
         Public Async Function TestDontRemoveNecessaryPredefinedCastWithToString() As Task

src/Workspaces/Core/Portable/Utilities/AbstractSpeculationAnalyzer.cs

@@ -540,8 +540,10 @@ private bool ReplacementBreaksSystemObjectMethodResolution(SyntaxNode currentOri
                 {
                     var previousOriginalType = this.OriginalSemanticModel.GetTypeInfo(previousOriginalNode).Type;
                     var previousReplacedType = this.SpeculativeSemanticModel.GetTypeInfo(previousReplacedNode).Type;
-
-                    return !Equals(previousOriginalType, previousReplacedType);
+                    if (previousReplacedType != null && previousOriginalType != null)
+                    {
+                        return !previousReplacedType.InheritsFromOrEquals(previousOriginalType);
+                    }
                 }
             }