// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
 
namespace Microsoft.CodeAnalysis
{
    /// <summary>
    /// Specifies the Ids of types that are expected to be defined in core library.
    /// Unlike ids in <see cref="SpecialType"/> enum, these ids are not meant for public consumption
    /// and are meant for internal usage in compilers.
    /// </summary>
    internal enum InternalSpecialType : sbyte
    {
        // Value 0 represents an unknown type
        Unknown = SpecialType.None,
 
        /// <summary>
        /// Indicates that the type is <see cref="System.ReadOnlySpan{T}"/> from the COR library.
        /// </summary>
        /// <remarks>
        /// Check for this special type cannot be used to find the "canonical" definition of <see cref="ReadOnlySpan{T}"/>
        /// since it is fully legal for it to come from sources other than the COR library, e.g. from `System.Memory` package.
        /// The <see cref="WellKnownType.System_ReadOnlySpan_T"/> should be used for that purpose instead
        /// This entry mostly exists so that compiler can tell this type apart when resolving other members of the COR library
        /// </remarks>
        System_ReadOnlySpan_T = SpecialType.Count + 1,
        First = System_ReadOnlySpan_T,
 
        System_IFormatProvider,
 
        /// <summary>
        /// Indicates that the type is <see cref="System.Type"/> from the COR library.
        /// </summary>
        /// <remarks>
        /// Check for this special type cannot be used to find the "canonical" definition of <see cref="System.Type"/>
        /// since it is fully legal for it to come from sources other than the COR library.
        /// The <see cref="WellKnownType.System_Type"/> should be used for that purpose instead
        /// This entry mostly exists so that compiler can tell this type apart when resolving other members of the COR library
        /// </remarks>
        System_Type,
 
        /// <summary>
        /// Indicates that the type is <see cref="System.Reflection.MethodBase"/> from the COR library.
        /// </summary>
        /// <remarks>
        /// Check for this special type cannot be used to find the "canonical" definition of <see cref="System.Reflection.MethodBase"/>
        /// since it is fully legal for it to come from sources other than the COR library.
        /// The <see cref="WellKnownType.System_Reflection_MethodBase"/> should be used for that purpose instead
        /// This entry mostly exists so that compiler can tell this type apart when resolving other members of the COR library
        /// </remarks>
        System_Reflection_MethodBase,
 
        /// <summary>
        /// Indicates that the type is <see cref="System.Reflection.MethodInfo"/> from the COR library.
        /// </summary>
        /// <remarks>
        /// Check for this special type cannot be used to find the "canonical" definition of <see cref="System.Reflection.MethodInfo"/>
        /// since it is fully legal for it to come from sources other than the COR library.
        /// The <see cref="WellKnownType.System_Reflection_MethodInfo"/> should be used for that purpose instead
        /// This entry mostly exists so that compiler can tell this type apart when resolving other members of the COR library
        /// </remarks>
        System_Reflection_MethodInfo,
 
        /// <summary>
        /// This item should be kept last and it doesn't represent any specific type.
        /// </summary>
        NextAvailable
    }
}