"unmanaged" IL 中的通用参数约束

Question

当我编译以下代码时：

type Class1<'T when 'T : unmanaged> =
    class end

type Class2<'T> =
    class end

在 IL 中它看起来像这样：

.class auto ansi serializable nested public Class1`1<T> extends [mscorlib]System.Object

.class auto ansi serializable nested public Class2`1<T> extends [mscorlib]System.Object

unmanaged 约束是否保存在某处？如果是这样，我在哪里以及如何以编程方式获取它？

在this question，我读到它是在"emdbedded signature file"的某个地方。那是什么？

Answer 1

这些约束位于存储在 FSharpSignatureData 托管资源中的实体数据中。可以使用来自 F# PowerPack 的 F# 元数据 Reader 浏览它们：

public static IList<FSharpGenericParameterConstraint> GetFSharpGenericParameterConstraints(Type genericType, int position)
{
    return GetFSharpGenericParameterConstraints(genericType.GetGenericArguments()[position]);
}

public static IList<FSharpGenericParameterConstraint> GetFSharpGenericParameterConstraints(Type genericParameter)
{
    var declMethod = genericParameter.DeclaringMethod;
    var declType = genericParameter.DeclaringType;
    var fsAsm = FSharpAssembly.FromAssembly(genericParameter.Assembly);
    int pos = genericParameter.GenericParameterPosition;
    var entities = AllEntities(fsAsm.Entities);
    if(declMethod != null)
    {
        var member = entities.SelectMany(e => e.MembersOrValues).First(m => m.ReflectionMemberInfo == declMethod);
        return member.GenericParameters[pos].Constraints;
    }else if(declType != null)
    {
        var entity = entities.First(e => e.ReflectionType == declType);
        return entity.GenericParameters[pos].Constraints;
    }
    return null;
}

private static IEnumerable<FSharpEntity> AllEntities(IEnumerable<FSharpEntity> entities)
{
    return entities.Concat(entities.SelectMany(e => AllEntities(e.NestedEntities)));
}

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bool unmanaged = GetFSharpGenericParameterConstraints(typeof(MyModule.Class1<>), 0).Any(c => c.IsUnmanagedConstraint);