How to know if read only property can be set in constructor?

[gao-artur]

Given the IPropertySymbol for the following properties:

// can be set in the constructor
public string P1 { get; }
// can't be set in constructor
public string P2 => "zzz";

In both cases, the SetMethod is null and IsReadOnly is true. How can I find out which one can be set in the constructor?

[CyrusNajmabadi]

Look at the property and see if there is an associated field. If so, it is an autoprop and can be set

[gao-artur]

This helped. Thanks!
I found this implementation:

public static bool IsAutoProperty(this IPropertySymbol property)
    => property.ContainingType.GetMembers().Any(static (member, property) => member is IFieldSymbol field && field.AssociatedSymbol == property, property);