Fix complex types in ctor (#74981)

Author: Saalvage

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

@@ -924,6 +924,12 @@ private static List<PropertyInfo> GetAllProperties([DynamicallyAccessedMembers(D
 
             var propertyBindingPoint = new BindingPoint(initialValue: config.GetSection(parameterName).Value, isReadOnly: false);
 
+            BindInstance(
+                parameter.ParameterType,
+                propertyBindingPoint,
+                config.GetSection(parameterName),
+                options);
+
             if (propertyBindingPoint.Value is null)
             {
                 if (ParameterDefaultValue.TryGetDefaultValue(parameter, out object? defaultValue))
@@ -936,12 +942,6 @@ private static List<PropertyInfo> GetAllProperties([DynamicallyAccessedMembers(D
                 }
             }
 
-            BindInstance(
-                parameter.ParameterType,
-                propertyBindingPoint,
-                config.GetSection(parameterName),
-                options);
-
             return propertyBindingPoint.Value;
         }
 

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

@@ -250,6 +250,12 @@ public class DerivedOptionsWithIConfigurationSection : DerivedOptions
 
         public record struct RecordStructTypeOptions(string Color, int Length);
 
+        public record RecordOptionsWithNesting(int Number, RecordOptionsWithNesting.RecordNestedOptions Nested1,
+            RecordOptionsWithNesting.RecordNestedOptions Nested2 = null!)
+        {
+            public record RecordNestedOptions(string ValueA, int ValueB);
+        }
+
         // Here, the constructor has three parameters, but not all of those match
         // match to a property or field
         public class ClassWhereParametersDoNotMatchProperties
@@ -2356,6 +2362,29 @@ public void CanBindRecordStructOptions()
             Assert.Equal("Green", options.Color);
         }
 
+        [Fact]
+        public void CanBindNestedRecordOptions()
+        {
+            var dic = new Dictionary<string, string>
+            {
+                {"Number", "1"},
+                {"Nested1:ValueA", "Cool"},
+                {"Nested1:ValueB", "42"},
+                {"Nested2:ValueA", "Uncool"},
+                {"Nested2:ValueB", "24"},
+            };
+            var configurationBuilder = new ConfigurationBuilder();
+            configurationBuilder.AddInMemoryCollection(dic);
+            var config = configurationBuilder.Build();
+
+            var options = config.Get<RecordOptionsWithNesting>();
+            Assert.Equal(1, options.Number);
+            Assert.Equal("Cool", options.Nested1.ValueA);
+            Assert.Equal(42, options.Nested1.ValueB);
+            Assert.Equal("Uncool", options.Nested2.ValueA);
+            Assert.Equal(24, options.Nested2.ValueB);
+        }
+
         [Fact]
         public void CanBindOnParametersAndProperties_PropertiesAreSetAfterTheConstructor()
         {