icsharpcode/ILSpy
Oct 2019 – Jul 2026
22 Months active
Languages Used
C#PowerShellXAMLXMLYAMLBatchILIL Assembly
Technical Skills
C# programmingcode quality improvementsoftware developmentC# Language FeaturesCode AnalysisDecompilation
Siegfried Pammer
PROFILE
Siegfried Pammer
Over several years, contributed to the icsharpcode/ILSpy repository by building and refining core decompilation features, modernizing the AST and slot system, and expanding support for evolving C# language versions. Applied deep knowledge of C#, .NET, and WPF to deliver robust decompiler pipelines, improve UI workflows, and enhance cross-platform reliability. Addressed complex challenges in code analysis, async/await lowering, and metadata handling, while maintaining high test coverage and code quality. Introduced extensible APIs, streamlined resource management, and strengthened error handling. The work enabled faster iteration, clearer output, and more maintainable code, supporting both end users and contributors in diverse development environments.
Overall Statistics
Feature vs Bugs
64%Features
Repository Contributions
466Total
Bugs
93
Commits
466
Features
164
Lines of code
410,509
Activity Months22
Your Network
27 peopleWork History
July 2026
69 Commits • 40 Features
Jul 1, 2026July 2026 ILSpy development focused on delivering a more productive debugging experience, stabilizing the decompilation pipeline, and expanding validation and build hygiene. Delivered user-facing UI improvements for the Debug Steps pane, hardened the debug-step replay flow, and implemented conservative defaults to reduce runtime overhead while preserving correctness. The team also advanced internal refactors for shared debugging infrastructure, expanded test coverage across language features, and improved cross-platform build robustness and documentation processing, all aligning with business value of faster triage, higher confidence releases, and broader contributor accessibility.
69 Commits • 40 Features
Jul 1, 2026July 2026 ILSpy development focused on delivering a more productive debugging experience, stabilizing the decompilation pipeline, and expanding validation and build hygiene. Delivered user-facing UI improvements for the Debug Steps pane, hardened the debug-step replay flow, and implemented conservative defaults to reduce runtime overhead while preserving correctness. The team also advanced internal refactors for shared debugging infrastructure, expanded test coverage across language features, and improved cross-platform build robustness and documentation processing, all aligning with business value of faster triage, higher confidence releases, and broader contributor accessibility.
July 2026
June 2026
160 Commits • 64 Features
Jun 1, 2026June 2026 monthly wrap-up for icsharpcode/ILSpy focused on stability, cross-platform reliability, and foundational architectural improvements that enable faster iteration and higher quality releases. Highlights include documentation alignment for .NET SDK requirements, build/runtime configuration hardening, substantial AST/DoMatch/slot-system modernization, and targeted UI/UX and testing improvements that reduce flaky behavior and improve developer and user experience.
June 2026
160 Commits • 64 Features
Jun 1, 2026June 2026 monthly wrap-up for icsharpcode/ILSpy focused on stability, cross-platform reliability, and foundational architectural improvements that enable faster iteration and higher quality releases. Highlights include documentation alignment for .NET SDK requirements, build/runtime configuration hardening, substantial AST/DoMatch/slot-system modernization, and targeted UI/UX and testing improvements that reduce flaky behavior and improve developer and user experience.
May 2026
25 Commits • 7 Features
May 1, 2026In May 2026, ILSpy development delivered a targeted set of user-facing features, reliability improvements, and code-quality enhancements across CLI tooling, async decompilation, and resource management. The team expanded the ILSpyCmd with BAML decompilation and resource enumeration, routed update-check messages to stderr to preserve stdout as a data channel, and introduced TransformAsyncHelpersAwaitToAwait to unify async decompilation handling. A broad set of runtime-async lowering fixes improved handling of non-Task task-likes, catch/finally and catch-with-when patterns, and multi-handler dispatch, significantly reducing edge-case decompilation errors. Resource and disposal improvements (MetadataFile) and test-coverage enhancements (Async ConfigureAwait/NoInlining) further tightened reliability and maintainability.
25 Commits • 7 Features
May 1, 2026In May 2026, ILSpy development delivered a targeted set of user-facing features, reliability improvements, and code-quality enhancements across CLI tooling, async decompilation, and resource management. The team expanded the ILSpyCmd with BAML decompilation and resource enumeration, routed update-check messages to stderr to preserve stdout as a data channel, and introduced TransformAsyncHelpersAwaitToAwait to unify async decompilation handling. A broad set of runtime-async lowering fixes improved handling of non-Task task-likes, catch/finally and catch-with-when patterns, and multi-handler dispatch, significantly reducing edge-case decompilation errors. Resource and disposal improvements (MetadataFile) and test-coverage enhancements (Async ConfigureAwait/NoInlining) further tightened reliability and maintainability.
May 2026
April 2026
7 Commits • 3 Features
Apr 1, 2026ILSpy (April 2026) — Key features and fixes delivered: Implemented C# 15 runtime-async lowering in the decompiler, including a new RuntimeAsync setting, language version bump, and ILReader adjustments, complemented by tests validating the runtime-async capabilities. Added dedicated tests to ensure correctness and compatibility of the runtime-async features. Enforced constructor accessibility rules to prevent transforming non-public constructors into primary constructors in abstract classes, preserving accurate accessibility semantics. Performed internal code quality improvements to formatting and comments (VisitQueryFromClause spacing and constrained-prefix cast notes). Updated the testing framework to Roslyn 4.14.0 and cleaned up the test suite by removing unused IL tests. Business impact: higher fidelity decompiled code for modern async patterns, safer constructor handling, faster and more reliable test runs, and a more maintainable codebase. Technologies/skills demonstrated: C# 15 runtime-async lowering, ILReader enhancements, MethodImplOptions handling, Roslyn 4.14.0 integration in tests, test automation, and code quality practices.
April 2026
7 Commits • 3 Features
Apr 1, 2026ILSpy (April 2026) — Key features and fixes delivered: Implemented C# 15 runtime-async lowering in the decompiler, including a new RuntimeAsync setting, language version bump, and ILReader adjustments, complemented by tests validating the runtime-async capabilities. Added dedicated tests to ensure correctness and compatibility of the runtime-async features. Enforced constructor accessibility rules to prevent transforming non-public constructors into primary constructors in abstract classes, preserving accurate accessibility semantics. Performed internal code quality improvements to formatting and comments (VisitQueryFromClause spacing and constrained-prefix cast notes). Updated the testing framework to Roslyn 4.14.0 and cleaned up the test suite by removing unused IL tests. Business impact: higher fidelity decompiled code for modern async patterns, safer constructor handling, faster and more reliable test runs, and a more maintainable codebase. Technologies/skills demonstrated: C# 15 runtime-async lowering, ILReader enhancements, MethodImplOptions handling, Roslyn 4.14.0 integration in tests, test automation, and code quality practices.
March 2026
1 Commits
Mar 1, 2026March 2026 monthly summary for icsharpcode/ILSpy: Delivered a targeted bug fix to ensure the Open in New Tab flag is correctly propagated during navigation events, with a focus on improving search-result handling and tabbed navigation UX.
1 Commits
Mar 1, 2026March 2026 monthly summary for icsharpcode/ILSpy: Delivered a targeted bug fix to ensure the Open in New Tab flag is correctly propagated during navigation events, with a focus on improving search-result handling and tabbed navigation UX.
March 2026
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026: Delivered Package Entry Handling and Saving Enhancements for ILSpy, including refactored extraction logic, new package-qualified file name properties, and streamlined saving of package entries. Fixed issue #3655 (ExtractPackageEntryContextMenuEntry) to restore reliable context-menu behavior. Result: more robust package entry management, improved UX for file handling, and clearer code paths across the package-entry workflow.
January 2026
1 Commits • 1 Features
Jan 1, 2026January 2026: Delivered Package Entry Handling and Saving Enhancements for ILSpy, including refactored extraction logic, new package-qualified file name properties, and streamlined saving of package entries. Fixed issue #3655 (ExtractPackageEntryContextMenuEntry) to restore reliable context-menu behavior. Result: more robust package entry management, improved UX for file handling, and clearer code paths across the package-entry workflow.
December 2025
18 Commits • 4 Features
Dec 1, 2025December 2025 (ILSpy) delivered substantial improvements in decompiler accuracy across platforms, clearer API change reporting, enhanced UX and localization, and stronger code quality and maintenance processes. These updates reduce debugging time, improve compatibility signals for downstream users, and streamline contributor workflows.
18 Commits • 4 Features
Dec 1, 2025December 2025 (ILSpy) delivered substantial improvements in decompiler accuracy across platforms, clearer API change reporting, enhanced UX and localization, and stronger code quality and maintenance processes. These updates reduce debugging time, improve compatibility signals for downstream users, and streamline contributor workflows.
December 2025
November 2025
18 Commits • 1 Features
Nov 1, 2025November 2025 focused on delivering a robust ILSpy decompiler experience with deeper support for modern language features, cross-assembly type resolution, and stability improvements. The team pushed a comprehensive feature set around records, constructors, and type handling, while also hardening the codebase against edge cases and improving developer tooling feedback.
November 2025
18 Commits • 1 Features
Nov 1, 2025November 2025 focused on delivering a robust ILSpy decompiler experience with deeper support for modern language features, cross-assembly type resolution, and stability improvements. The team pushed a comprehensive feature set around records, constructors, and type handling, while also hardening the codebase against edge cases and improving developer tooling feedback.
October 2025
9 Commits • 1 Features
Oct 1, 2025October 2025 monthly summary for icsharpcode/ILSpy focusing on delivering user-centric UI improvements and strengthening decompiler accuracy, with clear business value in usability and reliability.
9 Commits • 1 Features
Oct 1, 2025October 2025 monthly summary for icsharpcode/ILSpy focusing on delivering user-centric UI improvements and strengthening decompiler accuracy, with clear business value in usability and reliability.
October 2025
September 2025
14 Commits • 6 Features
Sep 1, 2025September 2025 performance summary for icsharpcode/ILSpy: Delivered core feature enhancements, stability fixes, and foundational work for future language features. Key outcomes include improved reliability through nullability annotations across SharpTreeNode and analyzer-related nodes; decompiler robustness with guards against nil tokens, improved folding, and correct handling of list initializers and closures; UI and error handling improvements in DebugDirectoryTreeNode with hex-formatted address displays; alignment with C# language features and attribute naming, plus groundwork for extension encoding; enhanced IL inspection by enabling custom attribute blob decoding in the IL disassembler and user-friendly SaveToDisk filename derivation. These changes reduce runtime errors, improve developer and user experience, and lay the groundwork for future IL extension features.
September 2025
14 Commits • 6 Features
Sep 1, 2025September 2025 performance summary for icsharpcode/ILSpy: Delivered core feature enhancements, stability fixes, and foundational work for future language features. Key outcomes include improved reliability through nullability annotations across SharpTreeNode and analyzer-related nodes; decompiler robustness with guards against nil tokens, improved folding, and correct handling of list initializers and closures; UI and error handling improvements in DebugDirectoryTreeNode with hex-formatted address displays; alignment with C# language features and attribute naming, plus groundwork for extension encoding; enhanced IL inspection by enabling custom attribute blob decoding in the IL disassembler and user-friendly SaveToDisk filename derivation. These changes reduce runtime errors, improve developer and user experience, and lay the groundwork for future IL extension features.
August 2025
24 Commits • 6 Features
Aug 1, 2025Month: 2025-08 — Focused on advancing language support, extension architecture, and reliability to accelerate developer workflows and ensure compatibility with the latest C# features. Key outcomes include updated C# language version support with tests, a refactored extension infrastructure, metadata table consolidation, expanded decompiler extension support, and targeted quality improvements with tooling upgrades.
24 Commits • 6 Features
Aug 1, 2025Month: 2025-08 — Focused on advancing language support, extension architecture, and reliability to accelerate developer workflows and ensure compatibility with the latest C# features. Key outcomes include updated C# language version support with tests, a refactored extension infrastructure, metadata table consolidation, expanded decompiler extension support, and targeted quality improvements with tooling upgrades.
August 2025
July 2025
19 Commits • 2 Features
Jul 1, 2025July 2025 monthly summary for icsharpcode/ILSpy focused on delivering tangible features, stabilizing the codebase, and enabling better tooling integration. Highlights include UI enhancements for code comparison navigation and diffs, centralized settings and CLI configuration for ILSpyX, and a broad set of stability and test improvements across TFMs and decompiler behavior. The work directly enhances developer productivity, reliability of decompilation, and expandability of configuration in automated pipelines.
July 2025
19 Commits • 2 Features
Jul 1, 2025July 2025 monthly summary for icsharpcode/ILSpy focused on delivering tangible features, stabilizing the codebase, and enabling better tooling integration. Highlights include UI enhancements for code comparison navigation and diffs, centralized settings and CLI configuration for ILSpyX, and a broad set of stability and test improvements across TFMs and decompiler behavior. The work directly enhances developer productivity, reliability of decompilation, and expandability of configuration in automated pipelines.
June 2025
15 Commits • 9 Features
Jun 1, 2025June 2025 monthly summary for icsharpcode/ILSpy: Delivered architectural, safety, and performance improvements to the decompiler and transformation pipeline. Highlights include simplification of DecompilerSettings with XML serialization removal and a virtual Clone(), InlineArrayTransform enhancements with constant slice support and post-order execution plus bounds checks, increased extensibility of the decompilation pipeline via a protected virtual CreateDecompiler, and advances in ReadOnlySpan/T-related ILInlining and overload resolution. Also fixed thread-safety in test scaffolding, contributing to more reliable automated tests. These changes improve extensibility, correctness, and runtime efficiency, delivering clearer decompiled output and faster property/isHidden checks with lower risk of regressions.
15 Commits • 9 Features
Jun 1, 2025June 2025 monthly summary for icsharpcode/ILSpy: Delivered architectural, safety, and performance improvements to the decompiler and transformation pipeline. Highlights include simplification of DecompilerSettings with XML serialization removal and a virtual Clone(), InlineArrayTransform enhancements with constant slice support and post-order execution plus bounds checks, increased extensibility of the decompilation pipeline via a protected virtual CreateDecompiler, and advances in ReadOnlySpan/T-related ILInlining and overload resolution. Also fixed thread-safety in test scaffolding, contributing to more reliable automated tests. These changes improve extensibility, correctness, and runtime efficiency, delivering clearer decompiled output and faster property/isHidden checks with lower risk of regressions.
June 2025
May 2025
7 Commits • 2 Features
May 1, 2025Month: 2025-05 — This period delivered core language feature support and stability improvements in ILSpy, focusing on expanding C# language compatibility, correctness around temporaries and spans, and UI reliability, while strengthening the test framework for broader platform coverage. The work drives stronger language support for users and more robust releases through improved test reliability and CI stability.
May 2025
7 Commits • 2 Features
May 1, 2025Month: 2025-05 — This period delivered core language feature support and stability improvements in ILSpy, focusing on expanding C# language compatibility, correctness around temporaries and spans, and UI reliability, while strengthening the test framework for broader platform coverage. The work drives stronger language support for users and more robust releases through improved test reliability and CI stability.
April 2025
12 Commits • 3 Features
Apr 1, 2025April 2025: Focused on stability, reliability, and platform readiness for ILSpy. Delivered new user-facing features with robust error handling, tightened UI behavior, and platform upgrades to support longer-term maintenance. Major bugs fixed improved diagram tooling, parameter handling, and state persistence, contributing to reduced support incidents and faster iteration cycles.
12 Commits • 3 Features
Apr 1, 2025April 2025: Focused on stability, reliability, and platform readiness for ILSpy. Delivered new user-facing features with robust error handling, tightened UI behavior, and platform upgrades to support longer-term maintenance. Major bugs fixed improved diagram tooling, parameter handling, and state persistence, contributing to reduced support incidents and faster iteration cycles.
April 2025
March 2025
25 Commits • 5 Features
Mar 1, 2025March 2025 ILSpy monthly summary focusing on readability, reliability, and Roslyn compatibility. Delivered key features that enhance code comprehension and expand language support: variable naming improvements across nested scopes with refined known-type naming for keywords like EventArgs, and parameter/local renaming to avoid collisions; LINQ decompiler enhancements to merge lambda parameter names when they refer to the same range variable; Roslyn 4.13 compatibility update to keep ILSpy aligned with the latest compiler changes; and CI improvements through a custom-built test-summary GitHub Action to improve feedback and reporting. Added broad language feature coverage with Private Protected support for 7.2 decompiler options. Major fixes improved correctness and stability across the decompilation pipeline, including preserving evaluation order, excluding delegate constructions from scope analysis, and correcting LocalFunctionDecompiler behavior in constructors, among others. Overall impact: higher fidelity decompiled output, reduced manual cleanup, faster onboarding for contributors, and more stable releases. Technologies/skills demonstrated: Roslyn integration (4.13), LINQ decompiler enhancements, scope/capture analysis, decompiler robustness fixes, UI/version propagation, and automated test workflows.
March 2025
25 Commits • 5 Features
Mar 1, 2025March 2025 ILSpy monthly summary focusing on readability, reliability, and Roslyn compatibility. Delivered key features that enhance code comprehension and expand language support: variable naming improvements across nested scopes with refined known-type naming for keywords like EventArgs, and parameter/local renaming to avoid collisions; LINQ decompiler enhancements to merge lambda parameter names when they refer to the same range variable; Roslyn 4.13 compatibility update to keep ILSpy aligned with the latest compiler changes; and CI improvements through a custom-built test-summary GitHub Action to improve feedback and reporting. Added broad language feature coverage with Private Protected support for 7.2 decompiler options. Major fixes improved correctness and stability across the decompilation pipeline, including preserving evaluation order, excluding delegate constructions from scope analysis, and correcting LocalFunctionDecompiler behavior in constructors, among others. Overall impact: higher fidelity decompiled output, reduced manual cleanup, faster onboarding for contributors, and more stable releases. Technologies/skills demonstrated: Roslyn integration (4.13), LINQ decompiler enhancements, scope/capture analysis, decompiler robustness fixes, UI/version propagation, and automated test workflows.
February 2025
18 Commits • 5 Features
Feb 1, 2025February 2025 monthly summary for icsharpcode/ILSpy focused on delivering high-fidelity decompilation for modern C# features, broader framework compatibility, and a smoother developer experience. Key outcomes include upgrades to decompiler accuracy, safer cross-target builds, standardized file handling across platforms, enhanced UI/UX and error messaging, and robustness improvements in core analysis pipelines.
18 Commits • 5 Features
Feb 1, 2025February 2025 monthly summary for icsharpcode/ILSpy focused on delivering high-fidelity decompilation for modern C# features, broader framework compatibility, and a smoother developer experience. Key outcomes include upgrades to decompiler accuracy, safer cross-target builds, standardized file handling across platforms, enhanced UI/UX and error messaging, and robustness improvements in core analysis pipelines.
February 2025
January 2025
12 Commits • 1 Features
Jan 1, 2025January 2025 — ILSpy: Focused on improving decompiler accuracy for switch statements, strengthening Roslyn parity, and boosting stability and usability. Implemented switch-value target-type preservation, refined conversions, and switch-on-string handling; delivered stability fixes for nullable type resolution, constructors handling, obfuscated-assembly scenarios, and UI navigation, resulting in fewer crashes and a smoother developer experience.
January 2025
12 Commits • 1 Features
Jan 1, 2025January 2025 — ILSpy: Focused on improving decompiler accuracy for switch statements, strengthening Roslyn parity, and boosting stability and usability. Implemented switch-value target-type preservation, refined conversions, and switch-on-string handling; delivered stability fixes for nullable type resolution, constructors handling, obfuscated-assembly scenarios, and UI navigation, resulting in fewer crashes and a smoother developer experience.
December 2024
3 Commits • 1 Features
Dec 1, 2024December 2024 monthly summary for icsharpcode/ILSpy focused on robustness, startup performance, and UI stability. Delivered targeted fixes and performance improvements that enhance reliability across .NET versions, speed up user workflows, and stabilize the docking-based UI. The work reduces maintenance risk and positions ILSpy for smoother onboarding of users with diverse target frameworks.
3 Commits • 1 Features
Dec 1, 2024December 2024 monthly summary for icsharpcode/ILSpy focused on robustness, startup performance, and UI stability. Delivered targeted fixes and performance improvements that enhance reliability across .NET versions, speed up user workflows, and stabilize the docking-based UI. The work reduces maintenance risk and positions ILSpy for smoother onboarding of users with diverse target frameworks.
December 2024
November 2024
7 Commits • 2 Features
Nov 1, 2024November 2024 focused on stabilizing and refining ILSpy's core tooling, improving test reliability, decompilation accuracy, and maintainability. Delivered several feature enhancements and critical bug fixes across the ILSpy repository, with emphasis on reducing duplication, improving error handling, and enhancing tree view and decompiler outputs. These efforts strengthen product reliability, developer productivity, and provide clearer, more accurate code representations for end users.
November 2024
7 Commits • 2 Features
Nov 1, 2024November 2024 focused on stabilizing and refining ILSpy's core tooling, improving test reliability, decompilation accuracy, and maintainability. Delivered several feature enhancements and critical bug fixes across the ILSpy repository, with emphasis on reducing duplication, improving error handling, and enhancing tree view and decompiler outputs. These efforts strengthen product reliability, developer productivity, and provide clearer, more accurate code representations for end users.
October 2024
1 Commits • 1 Features
Oct 1, 2024Concise monthly summary for 2024-10 focusing on ILSpy work: delivered a targeted decompiler filtering improvement and ensured high accuracy in edge cases, with emphasis on business value and technical merit.
1 Commits • 1 Features
Oct 1, 2024Concise monthly summary for 2024-10 focusing on ILSpy work: delivered a targeted decompiler filtering improvement and ensured high accuracy in edge cases, with emphasis on business value and technical merit.
October 2024
October 2019
1 Commits
Oct 1, 2019For 2019-10, ILSpy continued to strengthen code-generation reliability by addressing a critical edge-case: ensuring that generated variable names do not collide with C# keywords. This fix reduces the risk of compile-time errors in downstream code that uses ILSpy-generated outputs and simplifies maintenance by preventing keyword-related naming issues.
October 2019
1 Commits
Oct 1, 2019For 2019-10, ILSpy continued to strengthen code-generation reliability by addressing a critical edge-case: ensuring that generated variable names do not collide with C# keywords. This fix reduces the risk of compile-time errors in downstream code that uses ILSpy-generated outputs and simplifies maintenance by preventing keyword-related naming issues.
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Quality Metrics
Correctness96.2%
Maintainability93.0%
Architecture91.8%
Performance86.8%
AI Usage51.0%
Skills & Technologies
Programming Languages
BatchC#ILIL AssemblyPowerShellSVGShellXAMLXMLYAML
Technical Skills
.NET Core .NET Framework C# NuGet Package Management Refactoring Test Automation Testing.NET.NET DevelopmentAPI DesignAPI DevelopmentAPI designASTAST AnalysisAST Generation
Repositories Contributed To
Overview of all repositories you've contributed to across your timeline