remove the ad-hoc stuff

Author: lbargaoanu

src/AutoMapper/Configuration/CtorParamConfigurationExpression.cs

@@ -62,7 +62,7 @@ public void MapFrom(string sourceMembersPath)
         _ctorParamActions.Add(cpm => cpm.MapFrom(sourceMembersPath, sourceMembers));
     }
 
-    public void ExplicitExpansion(bool value = true) => _ctorParamActions.Add(cpm => cpm.ExplicitExpansion = value);
+    public void ExplicitExpansion(bool value) => _ctorParamActions.Add(cpm => cpm.ExplicitExpansion = value);
 
     public void Configure(TypeMap typeMap)
     {

src/AutoMapper/Configuration/MemberConfigurationExpression.cs

@@ -80,7 +80,7 @@ private void PreConditionCore(Expression<Func<TSource, TDestination, ResolutionC
         PropertyMapActions.Add(pm => pm.PreCondition = expr);
     public void AddTransform(Expression<Func<TMember, TMember>> transformer) =>
         PropertyMapActions.Add(pm => pm.AddValueTransformation(new ValueTransformerConfiguration(pm.DestinationType, transformer)));
-    public void ExplicitExpansion(bool value = true) => PropertyMapActions.Add(pm => pm.ExplicitExpansion = pm.ExplicitExpansion == null ? value : pm.ExplicitExpansion);
+    public void ExplicitExpansion(bool value) => PropertyMapActions.Add(pm => pm.ExplicitExpansion = value);
     public void Ignore() => Ignore(ignorePaths: true);
     public void Ignore(bool ignorePaths)
     {

src/IntegrationTests/ExplicitExpansion/ConstructorExplicitExpansionOverride.cs

@@ -0,0 +1,38 @@
+namespace AutoMapper.IntegrationTests.ExplicitExpansion;
+
+public class ConstructorExplicitExpansionOverride : IntegrationTest<ConstructorExplicitExpansionOverride.DatabaseInitializer> {
+    public class Entity {
+        public int Id { get; set; }
+        public string Name { get; set; }
+    }
+
+    public class SubEntity : Entity {
+    }
+
+    record Dto(string Name);
+    record SubDto(string Name) : Dto(Name) { }
+
+    public class Context : LocalDbContext {
+        public DbSet<Entity> Entities { get; set; }
+        public DbSet<SubEntity> SubEntities { get; set; }
+    }
+    public class DatabaseInitializer : DropCreateDatabaseAlways<Context> {
+        protected override void Seed(Context context) {
+            context.Entities.Add(new() { Name = "base" });
+            context.SubEntities.Add(new() { Name = "derived" });
+            base.Seed(context);
+        }
+    }
+    protected override MapperConfiguration CreateConfiguration() => new(c => {
+        c.CreateMap<Entity, Dto>().ForCtorParam("Name", o => o.ExplicitExpansion());
+        c.CreateMap<SubEntity, SubDto>().IncludeBase<Entity, Dto>().ForCtorParam("Name", o => o.ExplicitExpansion(false));
+    });
+    [Fact]
+    public void Should_work() {
+        using var context = new Context();
+        var dtos = ProjectTo<Dto>(context.Entities).ToList();
+        dtos.Count.ShouldBe(2);
+        dtos[0].ShouldBeOfType<Dto>().Name.ShouldBeNull();
+        dtos[1].ShouldBeOfType<SubDto>().Name.ShouldBe("derived");
+    }
+}

src/IntegrationTests/ExplicitExpansion/DisableExplicitExpansion.cs

@@ -1,6 +1,6 @@
 namespace AutoMapper.IntegrationTests.ExplicitExpansion;
 
-public class ExpandCollectionsWithoutExplicit : IntegrationTest<ExpandCollectionsWithoutExplicit.DatabaseInitializer>
+public class ExpandCollectionsOverride : IntegrationTest<ExpandCollectionsOverride.DatabaseInitializer>
 {
     TrainingCourseDto _course;