// 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.Diagnostics;

namespace Microsoft.CodeAnalysis.FindSymbols.Finders;

internal sealed partial class ExplicitConversionSymbolReferenceFinder
{
    private sealed class UnderlyingNamedTypeVisitor : SymbolVisitor<INamedTypeSymbol?>
    {
        public static readonly UnderlyingNamedTypeVisitor Instance = new();

        private UnderlyingNamedTypeVisitor()
        {
        }

        public override INamedTypeSymbol? VisitArrayType(IArrayTypeSymbol symbol)
            => Visit(symbol.ElementType);

        public override INamedTypeSymbol? VisitDynamicType(IDynamicTypeSymbol symbol)
            => null;

        public override INamedTypeSymbol? VisitFunctionPointerType(IFunctionPointerTypeSymbol symbol)
            => null;

        public override INamedTypeSymbol? VisitPointerType(IPointerTypeSymbol symbol)
            => Visit(symbol.PointedAtType);

        public override INamedTypeSymbol? VisitTypeParameter(ITypeParameterSymbol symbol)
            => null;

        public override INamedTypeSymbol? VisitNamedType(INamedTypeSymbol symbol)
            => symbol;

        public override INamedTypeSymbol? DefaultVisit(ISymbol symbol)
        {
            Debug.Fail($"Symbol case not handled: {symbol.Kind}");
            return base.DefaultVisit(symbol);
        }
    }
}