Fix: Incorrect casting when assigning Enum to custom type

- Modified TypeConversionAnalyzer.cs to use EnumCastThenConversion for all non-enum types, ensuring that the necessary cast through the underlying type is generated (e.g. `(MyType)(int)MyEnum.Value1`).
- Added unit test Issue1211_EnumToCustomTypeImplicitConversionAsync to ensure regressions don't occur.

Co-authored-by: GrahamTheCoder <2490482+GrahamTheCoder@users.noreply.github.com>

Author: google-labs-jules[bot]

CodeConverter/CSharp/TypeConversionAnalyzer.cs

@@ -165,7 +165,7 @@ public TypeConversionKind AnalyzeConversion(VBSyntax.ExpressionSyntax vbNode, bo
                 return TypeConversionKind.Identity;
             }
 
-            if (vbConvertedType.SpecialType == SpecialType.System_String) {
+            if (!vbConvertedType.IsEnumType()) {
                 return TypeConversionKind.EnumCastThenConversion;
             }
             return TypeConversionKind.Conversion;

Tests/CSharp/ExpressionTests/ExpressionTests.cs

@@ -2931,4 +2931,72 @@ public object Edit(bool flag2 = false, CrashEnum? crashEnum = default)
     }
 }");
     }
-}
+
+    [Fact]
+    public async Task Issue1211_EnumToCustomTypeImplicitConversionAsync()
+    {
+        await TestConversionVisualBasicToCSharpAsync(
+            @"Public Class Class1
+    Enum MyEnum
+        Value1 = 1
+    End Enum
+
+    Public Structure MyType
+        Public val As Integer
+        Public Shared Widening Operator CType(ByVal p As Integer) As MyType
+            Return New MyType With {.val = p}
+        End Operator
+        Public Shared Operator =(ByVal p As MyType, ByVal q As MyType) As Boolean
+            Return p.val = q.val
+        End Operator
+        Public Shared Operator <>(ByVal p As MyType, ByVal q As MyType) As Boolean
+            Return p.val <> q.val
+        End Operator
+    End Structure
+
+    Public Function Col(name As String) As MyType
+        Return Nothing
+    End Function
+
+    Public Sub Foo()
+        Dim b = Col(""foo"") = MyEnum.Value1
+    End Sub
+End Class",
+            @"
+public partial class Class1
+{
+    public enum MyEnum
+    {
+        Value1 = 1
+    }
+
+    public partial struct MyType
+    {
+        public int val;
+        public static implicit operator MyType(int p)
+        {
+            return new MyType() { val = p };
+        }
+        public static bool operator ==(MyType p, MyType q)
+        {
+            return p.val == q.val;
+        }
+        public static bool operator !=(MyType p, MyType q)
+        {
+            return p.val != q.val;
+        }
+    }
+
+    public MyType Col(string name)
+    {
+        return default;
+    }
+
+    public void Foo()
+    {
+        bool b = Col(""foo"") == (MyType)(int)MyEnum.Value1;
+    }
+}");
+    }
+
+}