/// <summary>
/// Visit new expressions for structural data types and transforms occurrences of entity types.
/// </summary>
/// <param name="node">The expression to transform.</param>
/// <param name="newType">The original type of the new expression.</param>
/// <returns>The new expression with the original type replaced with the new type.</returns>
protected virtual Expression VisitNewStructuralDataType(NewExpression node, StructuralTypeSlim newType)
{
if (node.Constructor is not DataModelConstructorInfoSlim oldConstructor || oldConstructor.ParameterMappings.Count != node.ArgumentCount)
{
throw new InvalidOperationException("Expected a constructor info instance with mapping attributes associated with constructor parameters.");
}
var n = oldConstructor.ParameterMappings.Count;
var memberAssignments = new Dictionary <MemberInfo, Expression>(n);
for (var i = 0; i < n; ++i)
{
var oldParameter = oldConstructor.ParameterMappings[i];
var oldArgument = node.GetArgument(i);
var newProperty = newType.Properties.Single(p => p.Name == oldParameter); // TODO: remove allocation
if (memberAssignments.ContainsKey(newProperty))
{
throw new InvalidOperationException(string.Format(CultureInfo.InvariantCulture, "Parameter mapping attribute '{0}' on the constructor of '{1}' is used more than once.", oldParameter, newType));
}
var newArgument = Visit(oldArgument);
memberAssignments[newProperty] = newArgument;
}
return(CreateNewExpression(newType, memberAssignments));
}
private object InvokeConstructor(NewExpression node)
{
int argCount = node.ArgumentCount();
object[] arguments = argCount > 0 ? new object[argCount] : Type.EmptyTypes;
for (int i = 0; i < argCount; i++)
{
arguments[i] = EvaluateArgument(node.GetArgument(i));
}
return(Activator.CreateInstance(node.Type, arguments));
}
