better error

Author: lbargaoanu

src/AutoMapper/Execution/ExpressionBuilder.cs

@@ -68,6 +68,7 @@ public static Expression MapExpression(this IGlobalConfiguration configuration,
         bool nullCheck;
         if (typeMap != null)
         {
+            typeMap.CheckProjection();
             var allowNull = memberMap?.AllowNull;
             nullCheck = !typeMap.HasTypeConverter && (destination.NodeType != ExpressionType.Default ||
                 (allowNull.HasValue && allowNull != profileMap.AllowNullDestinationValues));

src/UnitTests/Projection/ProjectCollectionListTest.cs

@@ -87,3 +87,26 @@ public override bool Equals(object obj)
         }
     }
 }
+public class MapProjection : AutoMapperSpecBase
+{
+    protected override MapperConfiguration CreateConfiguration() => new(cfg =>
+    {
+        cfg.CreateProjection<Address, AddressDto>();
+        cfg.CreateMap<Customer, CustomerDto>();
+    });
+    [Fact]
+    public void ShouldNotMap() => new Action(() => Map<CustomerDto>(new Customer())).ShouldThrow<AutoMapperConfigurationException>().Message.ShouldBe("CreateProjection works with ProjectTo, not with Map.");
+    public class Customer
+    {
+        public IList<Address> Addresses { get; set; }
+    }
+    public record class Address(string Street);
+    public class CustomerDto
+    {
+        public IList<AddressDto> Addresses { get; set; }
+    }
+    public class AddressDto
+    {
+        public string Street { get; set; }
+    }
+}