ILSpy 6.0

Major Changes of Note

• ILSpy 6.0 sports a multi-tab docking interface
• ILSpy 6.0 comes with a new Metadata Explorer
• ILSpy 6.0 has new icons for high-DPI support
• ILSpy 6.0 requires at least .NET 4.7.2 (v5.0 required .NET 4.6.2)

New Language Features

• C# 8.0: Indexing and Slices (Ranges)
• C# 7.0: Changes to syntactic disambiguation of generic identifiers
• C# 7.3 pattern-based fixed statement
• C# 8.0 Default Interface Methods
• C# 8.0 Async streams (currently not covering await foreach)
• C# 8.0 await using
• C# 8.0 Readonly members
• Decompile calli instructions using C# 9.0 function pointer syntax
• Improved support for Unsafe intrinsics
• Support for generic and static local functions

UI Improvements

• Docking and multi tab support (see #1725 and #1801)
• Metadata Explorer (see https://github.com/icsharpcode/ILSpy/wiki/Metadata-Explorer)
• Assembly list dropdown in toolbar, enhanced assembly list management
• Show target frameworks next to the assembly version in the tree-view
• Using the middle mouse button to click on tree nodes and links will open the decompilation result in a new tab.
• "Select PDB" context menu: allows to change the PDB file resolved by ILSpy or pick one from a different location
• Added a "Debug Metadata Explorer" node for portable PDBs
• Use XAML for icons (high DPI)
• New icons (based on VS 2017 icon pack) (#1704 thanks to @Rpinski)
• RichText Tooltips (#1654)
• Add "Open with ILSpy" entry to the Windows Explorer context menu on exe and dll files (via Options/Misc)
• Empty metadata tables can now be hidden from the tree view
• Folding for XAML output (thanks to @jogibear9988)
• Add "Reset to defaults" in Options dialog
• Dynamic assembly list generation for target framework

Improvements & Bugfixes

• Project export: Added an option to allow SDK-style format for project files. (#2031 by @dymanoid)
• Solution and project decompilation: Add missing ProjectTypeGuids
• Add search features (thanks to @miloush and @sailro)
• #1498: Remove Fusion API usage: Use standard file enumeration instead. This should enable us to use the GAC even with restricted access, as only the LIST permission is required.
• Fix DotNetCorePathFinder to properly support netstandard2.1
• Fix multi-module support
• Updated links to MS Docs (#2030 by @AustinWise)
• Improve ReduceNestingTransform by considering nested containers (#1880 by @Chicken-Bones)
• Analyzers: Added "Implements interface"-Analyzer (#2028 by @dymanoid)
• Analyzer follow type forwarders (#1846 by @yyjdelete)
• The decompiler now supports Scalar Replacement Of Aggregates, which by default only works on display-classes and display-structs. There is an option to make it affect all instances and uses of plain types containing fields only. NOTE: It is still in preview stage. You can activate it when using a debug build.
• Added support for null-propagation on unconstrained generic expressions
• Added support for [module: NullablePublicOnly]
• Enhanced assembly resolution to distinguish target frameworks and use the correct references in case there are multiple versions of framework assemblies loaded.
• Better decompilation of local functions, pinned regions and display-classes
• Disassembler: actually make use of the cancellation token
• Support VB Select Case on string
• Display System.Void as struct (#1835 by @yyjdelete)
• Properly decompile auto events with tuples
• Do not change accessibility of non-transformed local functions
• Improve drag&drop support (#1860)
• Fix bug in stackalloc initializer detection involving Span<decimal> (see #1855 by @yyjdelete)
• Added struct constructor initializer pattern
• DotNetCorePathFinder: Various bug fixes when working with .net core assemblies
• Transform post-increment on float/double (#1769 thanks to @Chicken-Bones)
• Fix extra minus sign when formatting -0 on .NET Core 3.0 (#1790 thanks to @Chicken-Bones)
• Fix sealed modifier on interface methods with no body (#1792 thanks to @Chicken-Bones)
• Fix NullReferenceException when foreach decompilation is turned off (#1754 thanks to @davidwengier)
• Fixed performance problem when using an assembly from a MemoryStream (#1763 thanks to @yyjdelete)

Ready2Run (R2R)

• Ready2Run (by @cshung see https://github.com/icsharpcode/ILSpy/wiki/ILSpy.ReadyToRun)
• IL/IL with C#/ReadyToRun: Add metadata token hyperlinks to type, field, property and event declarations.
• IL/IL with C#/ReadyToRun: Add rich-text tooltips
• ReadyToRun: Optional output of UnwindInfo (#2043 by @edkazcarlson)
• ReadyToRun: Using import cell name to describe callees (#1991 by @cshung)
• ReadyToRun: Decorate the ready to run disassembly with DebugInfoBounds (#1987 by @cshung)

PDB Generation

• Improved sequence points of try-catch statements
• Improved generation of sequence points (#1967 by @jacdavis)
• PDB generation: Use correct sequence points in LINQ expressions and many smallish bug fixes

dotnet ilspycmd Tool

• New option: usepdb (for improved variable naming)
• Breaking change: option debuginfo renamed to genpdb
• #1740: Add LanguageVersion, RemoveDeadCode and RemoveDeadStores switches

ILSpy pwsh cmdlets

• Show a progress bar during decompilation

ILSpy 6.0 RC1

New Language Features

• Decompile calli instructions using C# 9.0 function pointer syntax
• Improved support for Unsafe intrinsics

Enhancements

• ReadyToRun: Optional output of UnwindInfo (#2043 by @edkazcarlson)

Bug fixes

• And many other fixes, for a full list click here

ILSpy 6.0 Preview 4

New Language Features

• C# 8.0: Indexing and Slices (Ranges)

New Features

• TEMPORARILY REMOVED #2013 (comment): Added the capability to extract self-contained executables (PublishSingleFile)
• Project export: Added an option to allow SDK-style format for project files. (#2031 by @dymanoid)
• Dynamic assembly list generation for target framework
• Analyzers: Added "Implements interface"-Analyzer (#2028 by @dymanoid)

UI Improvements

• Using the middle mouse button to click on tree nodes and links will open the decompilation result in a new tab.
• IL/IL with C#/ReadyToRun: Add metadata token hyperlinks to type, field, property and event declarations.
• IL/IL with C#/ReadyToRun: Add rich-text tooltips
• Show target frameworks next to the assembly version in the tree-view

Enhancements

• ReadyToRun: Using import cell name to describe callees (#1991 by @cshung)
• ReadyToRun: Decorate the ready to run disassembly with DebugInfoBounds (#1987 by @cshung)
• Improve ReduceNestingTransform by considering nested containers (#1880 by @Chicken-Bones)
• The decompiler now supports Scalar Replacement Of Aggregates, which by default only works on display-classes and display-structs. There is an option to make it affect all instances and uses of plain types containing fields only. NOTE: It is still in preview stage. You can activate it when using a debug build.
• Added support for null-propagation on unconstrained generic expressions
• Added support for [module: NullablePublicOnly]
• Enhanced assembly resolution to distinguish target frameworks and use the correct references in case there are multiple versions of framework assemblies loaded.
• Updated links to MS Docs (#2030 by @AustinWise)
• #1498: Remove Fusion API usage: Use standard file enumeration instead. This should enable us to use the GAC even with restricted access, as only the LIST permission is required.

PDB generation

• Improved sequence points of try-catch statements

Bug fixes

• Fix #1946: Don't move return into try block when doing so changes the semantics of a finally block.
• Fix #1992: Analyzer fails to find usages of a type when it is used as a type argument
• Workaround dotnet/roslyn#43659 in decompiled code.
• And many other fixes, for a full list click here.

ILSpy 6.0 Preview 3

An administrative note first: we re-licensed the last part that came from SharpDevelop - the tree view component. It happened more for consistency in the repository than any other reason. You can find the discussions at #1904.

New Language Features

• C# 7.0: Changes to syntactic disambiguation of generic identifiers

UI Improvements

• Add "Open with ILSpy" entry to the Windows Explorer context menu on exe and dll files (via Options/Misc)
• Added a "Debug Metadata Explorer" node for portable PDBs
• Empty metadata tables can now be hidden from the tree view
• "Select PDB" context menu: allows to change the PDB file resolved by ILSpy or pick one from a different location
• Various stability fixes

Enhancements

• ReadyToRun: Fix #1889 Indexing the methods
• ReadyToRun: Avoid eager parsing (#1934 by @cshung)
• Better decompilation of local functions, pinned regions and display-classes
• Solution and project decompilation: Add missing ProjectTypeGuids

PDB generation

• Improved generation of sequence points (#1967 by @jacdavis)
• PDB generation: Use correct sequence points in LINQ expressions and many smallish bug fixes

Bug fixes

• Fix multi-module support
• Disassembler: actually make use of the cancellation token
• And many other fixes, for a full list click here.

ILSpy pwsh cmdlets

• Show a progress bar during decompilation

Fixes and improvements for SharpLab

• Do not run ProxyCallReplacer if async state machines are not transformed.
• Do not show readonly modifier on structs, if the IsReadonlyAttribute is preserved.
• Provide a setting to desugar X? into Nullable for value types.

ILSpy 6.0 Preview 2

UI Improvements

• Ready2Run (by @cshung see https://github.com/icsharpcode/ILSpy/wiki/ILSpy.ReadyToRun)
• Metadata Explorer (see https://github.com/icsharpcode/ILSpy/wiki/Metadata-Explorer)
• Assembly list dropdown in toolbar, enhanced assembly list management
• Add "Reset to defaults" in Options dialog

New Language Features

• Support for generic and static local functions
• C# 7.3 pattern-based fixed statement

Enhancements

• Support VB Select Case on string
• Analyzer follow type forwarders (#1846 by @yyjdelete)

Bug fixes

• Display System.Void as struct (#1835 by @yyjdelete)
• Properly decompile auto events with tuples
• Do not change accessibility of non-transformed local functions
• Improve drag&drop support (#1860)
• Fix bug in stackalloc initializer detection involving Span<decimal> (see #1855 by @yyjdelete)
• Fix DotNetCorePathFinder to properly support netstandard2.1

dotnet ilspycmd Tool

• New option: usepdb (for improved variable naming)
• Breaking change: option debuginfo renamed to genpdb

ILSpy 6.0 Preview 1

BREAKING CHANGES / IN DEVELOPMENT

• The main new UI feature is a multi-tab docking interface. Please put it to the test and report bugs!
• ILSpy 6.0 will require at least .NET 4.7.2 (v5.0 required .NET 4.6.2)

New Language Features

• C# 8.0 Default Interface Methods
• C# 8.0 Async streams (currently not covering await foreach)
• C# 8.0 await using
• C# 8.0 Readonly members

New Features

• Add search features (thanks to @miloush and @sailro)
  • resources (#1707)
  • assemblies (#1708)
  • namespaces (#1736)
  • Add assembly column to search pane (#1690)

Decompiler Engine Improvements & Bugfixes

• Added struct constructor initializer pattern
• DotNetCorePathFinder: Various bug fixes when working with .net core assemblies
• Transform post-increment on float/double (#1769 thanks to @Chicken-Bones)
• Fix extra minus sign when formatting -0 on .NET Core 3.0 (#1790 thanks to @Chicken-Bones)
• Fix sealed modifier on interface methods with no body (#1792 thanks to @Chicken-Bones)
• Fix NullReferenceException when foreach decompilation is turned off (#1754 thanks to @davidwengier)
• Fixed performance problem when using an assembly from a MemoryStream (#1763 thanks to @yyjdelete)

UI Improvements

• New icons (based on VS 2017 icon pack) (#1704 thanks to @Rpinski)
• Use XAML for icons (high DPI)
• Docking and multi tab support (see #1725 and #1801)
• RichText Tooltips (#1654)
• Folding for XAML output (thanks to @jogibear9988)

dotnet ilspycmd Tool

• #1740: Add LanguageVersion, RemoveDeadCode and RemoveDeadStores switches

ILSpy 5.0.2

This is a bug fix release.

• Fix crash while resolving .NET core references
• Respect language settings in display class transformation
• Use specialized generic types if a specialized variable is captured
• Stack overflow when decompiling a bool -> bool? conversion
• Expand using declarations setting was not saved

ILSpy 5.0.1

This is a bug fix release.

• VSIX: Fixes for reference assemblies, type navigation
• PDBgen: Fix for sequence points generation
• Add support for null propagation on array access: arr?[i]
• Additional smaller fixes and improvements

ILSpy 5.0

ILSpy 5.0

New Language Features

• C# 8.0: Nullable Reference Types
• C# 7.3: unmanaged generic constraint
• C# 7.3 Indexing movable fixed buffers: Fixed buffers can be indexed into without first being pinned.
• Use Unsafe intrinsics to represent IL operations that cannot be expressed in C#.
• C# 7.0 Generalized async return types
• C# 7.0 Local functions (#1586)
• C# 7.0 Throw expressions (#1600)

New Features

• Decompile a set of assemblies to a solution (#1550 by @dymanoid)
• New BAML Decompiler
• MSIX for Microsoft Store: @onovotny added build support (including Azure Pipelines).
• Generate VS Windows Forms Designer-compliant code if a method is identified as Windows Forms InitializeComponent
• Added new RemoveDeadStores option.
• Added new AlwaysShowEnumMemberValues option.

Decompiler Engine Improvements & Bugfixes

• Improved stability of decompiler and disassembler on invalid metadata tokens.
• Improved decompilation in case not all types/references are available.
• Added switch-on-string pattern for empty string case.
• Add support for ReadOnlySpan<T> initialization pattern
• Improved decompilation of ref readonly delegates and return types.
• • Improved decompilation of ref typed expressions, in particular ref/in extension methods and in parameters.
• Improved support for Mono yield return state machines and closure types.
• Improved decompilation of LINQ queries
• PDB generator now can emit "method stepping information" for async #1422

Improvements & Bugfixes

• Many minor bug and stability fixes.
• Improved performance in ILInlining step
• VSIX: Fix issue of missing dependencies

UI Improvements

• Avoid blocking the UI when waiting on assembly load while restoring the saved position in the treeview
• Support obfuscated names in treeview and search #1359
• Escape non-printable characters in IL view
• Rework C# decompiler options dialog (unify language settings panel)
• Make indentation of decompiled code configurable.
• Chinese translation by @maikebing (#1299) screenshots
• Small improvements in search panel by @mcpiroman (#1476)
• Show error message if an entity cannot be analyzed instead of crashing.
• Improved linking in the decompiler view:
  • method group / delegate references
  • the constructor of an attribute is reachable, by clicking on the open/close parenthesis.
  • fixed fields are now properly linked
• Added matching bracket highlighting
• Updated to AvalonEdit 6.0 Preview

dotnet ilspycmd Tool

• Add -d|-debuginfo option See Demo app
• Add -r|-referencepath option

Architectural Changes

• We dropped support for all TFMs except netstandard2.0 #1416
• Reactivate many tests from old decompiler

Known issues & limitations

• C# 8.0 nullable reference types metadata only supports the latest format. Note that this is a breaking change and assemblies generated by older preview versions of C# 8 are not supported. (See #1619 (comment))
• Generic local functions are not yet supported (#1588)
• "Open assembly from GAC" may require administrator privileges (#1498)
• Matching bracket highlighting does not yet support all language features that introduce new syntax.

ILSpy 5.0 RC1

New Language Features

• C# 7.0 Generalized async return types

Improvements & Bugfixes

• Added new RemoveDeadStores option.
• Added switch-on-string pattern for empty string case.
• Improved decompilation in case not all types/references are available.
• Many minor bug and stability fixes.