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// 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.Collections.Generic;
using System.Diagnostics;
namespace Microsoft.CodeAnalysis.CSharp.Symbols
{
internal static class TypeParameterSymbolExtensions
{
public static bool DependsOn(this TypeParameterSymbol typeParameter1, TypeParameterSymbol typeParameter2)
{
Debug.Assert((object)typeParameter1 != null);
Debug.Assert((object)typeParameter2 != null);
Stack<TypeParameterSymbol>? stack = null;
HashSet<TypeParameterSymbol>? visited = null;
while (true)
{
foreach (var constraintType in typeParameter1.ConstraintTypesNoUseSiteDiagnostics)
{
if (constraintType.Type is TypeParameterSymbol typeParameter)
{
if (typeParameter.Equals(typeParameter2))
{
return true;
}
visited ??= new HashSet<TypeParameterSymbol>();
if (visited.Add(typeParameter))
{
stack ??= new Stack<TypeParameterSymbol>();
stack.Push(typeParameter);
}
}
}
if (stack is null || stack.Count == 0)
{
break;
}
typeParameter1 = stack.Pop();
}
return false;
}
}
}
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