ReSharper の新機能 
ReSharper の新機能 Welcome to the ReSharper 2026.1 release overview. This version is designed to make everyday .NET development more comfortable and efficient, with:
Marking a new step in the evolution of performance monitoring, ReSharper 2026.1 introduces the モニター tool window. This new dedicated tool window provides a clearer, more complete picture of runtime performance and offers automated issue detection to help you identify optimization opportunities.
The モニター tool window lets you observe key runtime metrics of your application as it runs or during debugging. It builds on the capabilities already previously available through our .NET profiling tools and Dynamic Program Analysis (DPA), but brings them together in a single view that makes it easier to evaluate runtime behavior at a glance.
Starting with ReSharper 2026.1, the Monitoring tool window is available when using ReSharper as part of the dotUltimate subscription.
The 動的プログラム分析 (DPA) feature will be retired in the 2026.2 release, while its core capabilities will continue to be provided through the new monitoring experience.
現在の制限:
The モニター tool window is not currently supported in アウトオブプロセスモード . We are working to remove this limitation in ReSharper 2026.2.
For more details on how monitoring works and how to use it, see our documentation.
ReSharper is now available for Visual Studio Code and compatible editors such as Cursor and Google Antigravity, bringing JetBrains ’ C# tooling to your editor of choice.
The extension provides real-time code analysis, refactorings, and navigation for C#, XAML, Razor, and Blazor. It also includes a ソリューションエクスプローラー for managing projects and source generators, as well as built-in unit testing support for NUnit, xUnit.net, and MSTest.
ReSharper for VS Code and compatible editors is available under the ReSharper, dotUltimate, and All Products Pack subscriptions. A free subscription is also available for non-commercial use.
Learn more in this dedicated blog post(英語).
ReSharper 2026.1 expands its support for C# extension members, helping you work more efficiently with the evolving language features.
A new 拡張メンバーを統合する context action merges compatible extension declarations and classic extension methods into a single block. The Import extension member quick-fix has also been improved and now supports all kinds of extension members, automatically adding missing using directives when needed.
We ’ ve also improved navigation and refactoring for extension members. ReSharper can now decompile extension blocks and navigate to generated sources, and the 静的に拡張する拡張メソッド refactoring now works with methods declared inside extension blocks.
ReSharper 2026.1 introduces early support for upcoming C# language updates, helping you experiment with new syntax as the language evolves.
This release includes initial support for collection expression arguments and support for the [ExtendedLayout] attribute, ensuring ReSharper continues to work smoothly with the latest compiler innovations.
This release adds several new inspections and style options to help you write safer and more consistent code.
ReSharper now detects short-lived HttpClient instances and suggests safer reuse patterns. It also warns you when ImmutableArray<T> is used with collection initializers, which can lead to a runtime NullReferenceException .
その他の改善点は次のとおりです:
string.Empty and "" .#nullable enable automatically in new files.[LoggerMessage] attributes.This release brings several performance improvements across indexing, code completion, and code analysis.
We reworked the indexing of annotated type members defined in assemblies, making it significantly faster and more memory efficient.
Import completion is now more responsive by eliminating certain expensive computations.
We also optimized several performance-critical code paths by reducing costly interface type checks, resulting in faster code analysis and lower overall overhead.
ReSharper 2026.1 improvements to C++ support include:
#embed directive, C++23 extended floating-point types, the C2Y _Countof operator, and other features.C++ のアップデートの詳細については、ReSharper C++ 2026.1 の新機能ページを参照してください。
We continue to improve the stability of ReSharper ’ s アウトオブプロセス (OOP) mode, which improves responsiveness and resilience by separating ReSharper ’ s backend from Visual Studio.
In this release, we resolved over 70 issues(英語) and made improvements related to the アウトオブプロセス architecture. The fixes address problems across a wide range of scenarios, including navigation (particularly ピーク actions), UI interactions, unit testing sessions, and solution state synchronization.
The .NET runtime used by ReSharper in アウトオブプロセス (OOP) mode has also been updated to .NET 10.
Several editor UI elements in ReSharper have been refreshed to better align with the modern look of the Visual Studio experience.
Thanks to a redesign, the code completion UI now provides a cleaner and more consistent look within the editor.
We also modernized a number of related UI components, including parameter info popups, tooltips, and other editor popups, replacing outdated visuals and improving their appearance across themes and DPI settings.
The updated UI now supports Visual Studio ’ s editor zoom feature , ensuring completion lists and parameter info scale correctly when zoom levels change.