ConfigurationBinder.Bind on virtual properties duplicates elements

src/libraries/Microsoft.Extensions.Configuration.Binder/src/ConfigurationBinder.cs

@@ -757,11 +757,30 @@ private static List<PropertyInfo> GetAllProperties(
             Type type)
         {
             var allProperties = new List<PropertyInfo>();
+            HashSet<string>? propertyNames = null;
 
             Type? baseType = type;
             do
             {
-                allProperties.AddRange(baseType!.GetProperties(DeclaredOnlyLookup));
+                PropertyInfo[] baseTypeProperties = baseType!.GetProperties(DeclaredOnlyLookup);
+
+                if (baseType != type)
+                {
+                    foreach (var property in baseTypeProperties)
+                    {
+                        if (propertyNames!.Add(property.Name))
+                        {
+                            allProperties.Add(property);
+                        }
+                    }
+                }
+                else
+                {
+                    propertyNames = new(baseTypeProperties.Select(mp => mp.Name),
+                    StringComparer.Ordinal);
+                    allProperties.AddRange(baseTypeProperties);
+                }
+
                 baseType = baseType.BaseType;
             }
             while (baseType != typeof(object));

src/libraries/Microsoft.Extensions.Configuration.Binder/tests/ConfigurationBinderTests.cs

@@ -1750,6 +1750,21 @@ public void CanBindNullableNestedStructProperties()
             Assert.True(bound.NullableNestedStruct.Value.DeeplyNested.Boolean);
         }
 
+        [Fact]
+        public void CanBindVirtualPropertiesWithoutDuplicates()
+        {
+            ConfigurationBuilder configurationBuilder = new();
+            configurationBuilder.AddInMemoryCollection(new Dictionary<string, string>
+            {
+                { "Test:0", "1" }
+            });
+            IConfiguration config = configurationBuilder.Build();
+
+            var test = new ClassOverridingVirtualProperty();
+            config.Bind(test);
+            Assert.Equal("1", Assert.Single(test.Test));
+        }
+
 
         private interface ISomeInterface
         {
@@ -1827,5 +1842,15 @@ public struct DeeplyNested
                 public bool Boolean { get; set; }
             }
         }
+
+        public class BaseClassWithVirtualProperty
+        {
+            public virtual string[] Test { get; set; } = System.Array.Empty<string>();
+        }
+
+        public class ClassOverridingVirtualProperty : BaseClassWithVirtualProperty
+        {
+            public override string[] Test { get => base.Test; set => base.Test = value; }
+        }
     }
 }