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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.Composition;
using System.Diagnostics.CodeAnalysis;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.UseIsNullCheck;
namespace Microsoft.CodeAnalysis.CSharp.UseIsNullCheck;
using static CSharpSyntaxTokens;
using static SyntaxFactory;
using static UseIsNullCheckHelpers;
[ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.UseIsNullCheckForReferenceEquals), Shared]
[method: ImportingConstructor]
[method: SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
internal sealed class CSharpUseIsNullCheckForReferenceEqualsCodeFixProvider()
: AbstractUseIsNullCheckForReferenceEqualsCodeFixProvider<ExpressionSyntax>
{
private static readonly LiteralExpressionSyntax s_nullLiteralExpression
= LiteralExpression(SyntaxKind.NullLiteralExpression);
private static readonly ConstantPatternSyntax s_nullLiteralPattern
= ConstantPattern(s_nullLiteralExpression);
protected override string GetTitle(bool negated, ParseOptions options)
=> UseIsNullCheckHelpers.GetTitle(negated, options);
private static SyntaxNode CreateEqualsNullCheck(ExpressionSyntax argument)
=> BinaryExpression(SyntaxKind.EqualsExpression, argument, s_nullLiteralExpression).Parenthesize();
private static SyntaxNode CreateIsNullCheck(ExpressionSyntax argument)
=> IsPatternExpression(argument, s_nullLiteralPattern).Parenthesize();
private static SyntaxNode CreateIsNotNullCheck(ExpressionSyntax argument)
{
if (SupportsIsNotPattern(argument.SyntaxTree.Options))
{
return IsPatternExpression(
argument,
UnaryPattern(
NotKeyword,
s_nullLiteralPattern)).Parenthesize();
}
else
{
return BinaryExpression(
SyntaxKind.IsExpression,
argument,
PredefinedType(ObjectKeyword)).Parenthesize();
}
}
protected override SyntaxNode CreateNullCheck(ExpressionSyntax argument, bool isUnconstrainedGeneric)
=> isUnconstrainedGeneric
? CreateEqualsNullCheck(argument)
: CreateIsNullCheck(argument);
protected override SyntaxNode CreateNotNullCheck(ExpressionSyntax argument)
=> CreateIsNotNullCheck(argument);
}
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