General

• Dark mode! (big thank you to @tom-englert in #2347)
• Building ILSpy for .NET 5 is now possible (see multitargeting.props.template)
• Added inline display of CustomDebugInformation table entries in metadata
• Add metadata tree nodes for blob, guid, string and user string heap

Contributions

• Performance improvements in DataGrid filter (thanks to @tom-englert)
• Adjust fitness calculation for destructors (by @MikeFH in #2344)
• Refactored insertion of search results (by @MikeFH in #2335)
• Use correct URL format in Search MSDN command (by @yyjdelete in #2343)
• Warning fixes (by @riQQ in #2345)
• Fixed ConnectionIdRewritePass (by @wwh1004 in #2327)

Bug fixes

• PDBGen: Ignore duplicated ILFunctions (see 5a8b488)
• #2314: ILSpy incorrectly resolves a runtime dependency when dll is present in both WindowsDesktop.App and NETCore.App
• #1648 and #2133: Use simple assembly names for KnownThings to allow the resolver to use the relative framework version.
• #2349: Use proper ExpressionType with DynamicCompoundAssign.
• #1512: XmlDocumentationProvider Unable to load some XML files to have special characters
• #2342: Do not generate empty names for foreach loop variables.
• #2340: Do not traverse assemblies with load errors in AssemblyList.GetAllAssemblies()
• #2356: Can't navigate if switch language in Analyze panel.
• Improved decompilation of rethrow/throw and finally blocks in async methods. (see #1749, #2339 and #2353)
• And many other fixes, for a full list click here.

General

• Detect use of csc /deterministic switch
• Update Ready2Run (see #2279 by @cshung)
• #2286: Enable server-mode GC in ILSpy
• Improve assembly resolver API to allow async usage

UI Improvements

• Search enabled in NuGet packages
• Enable theming for message boxes (see #2276 by @AustinWise)

Bug fixes

• #2278: Implement support for CSharpBinderFlags.InvokeSimpleName
• #2280: Add additional checks to GenerateVariableName
• #2275: Fix exception when assembly does not contain proper MetadataVersion.
• #2260: Fix switch(string) transform: handle empty cases where the C# compiler optimizes out the if
• #2288: Fix decompilation of nullable lifting in expression trees (by @wwh1004)
• And many other fixes, for a full list click here.

New Language Features

• C# 9.0: record classes
• C# 9.0: with expressions
• C# 9.0: primary constructors

General

• Removed the dependency on Humanizer (see #2232 and #2235)
• Updated ReadyToRun (see #2238, by @cshung)

UI Improvements

• Added setting highlight the current line in the code view (see #2224, by @DickvdBrink)
• Fix #2205: About page should always be opened in a new tab.

Bug fixes

• Fix #1079: CSharpFormattingOptions.AutoPropertyFormatting has no effect
• Fix #2222: switch-expression does not support implicit conversions.
• #2241: Fix possible NRE in TypeProvider.GetTypeFromReference
• Fix #2233: ResourcesFileTreeNode no longer creates child nodes for BAML files
• Fix #2230: do not emit directly consecutive null propagation operators.
• Fix #603: Single element arrays should not span multiple lines
• Fixed crash when loading DLLs with invalid sections in their .deps.json (see #2227, by @bernd5)
• And many other fixes, for a full list click here.

Important note for consumers of our ICSharpCode.Decompiler NuGet package: we have aligned our dependencies with Roslyn 3.8.0, see #2173

New Language Features

• Add support for .NET 5 custom calling conventions.
• Improved support for Unsafe-intrinsics

UI Improvements

• .NET bundles and Nuget packages are now directly embedded in the tree view.

General

• Improved project/solution decompilation (see #2186, by @wwh1004)
• Support for .NET bundles (see #2191)
• Supports code generated by Roslyn 3.8.0

Bug fixes

• Fix #2192: Add support for VB.NET delegate construction
• Fix #2195: foreach loop conversion accidentally removes end container labels
• Fix #2197: .NET 5 RC2: "Analyze/Used By" throws BadImageFormatException
• Fix #2196: Add support for extern local functions.
• And many other fixes, for a full list click here.

This is a bugfix release.

• #2177: PDB Generation is confused by enhanced using statements
• #2183: Incorrect version in binding redirect for AvalonEdit
• #2174: Some compilers produce display class ctors with unused local variables
• #2182: Do not inline switch value, in case variable is reused.
• #2180: Restrict the (uint?)-1 special case to casts to integer types.
• #2185: Fix MemberIsHidden-check for local function display structs

New Language Features

• C# 7.0: Deconstruction
• C# 8.0: await foreach
• C# 8.0: Disposable ref structs
• C# 8.0: Enhanced using statements
• C# 8.0: switch expressions
• C# 9.0: init accessors
• C# 9.0: function pointers (see #2150)
• C# 9.0: foreach with GetEnumerator extension methods
• C# 9.0: Lambda parameter discards

General

• Add an option to enable aggressive inlining of expressions
• Add option for string.Concat decompilation
• Add an option to always qualify member references (by @Pathoschild, see #2114)
• ReadyToRun: Variable tracking in output (by @edkazcarlson, see #2067)
• ReadyToRun: Optimized debug info output (by @cshung, see #2113)
• Work on unifying the code formatting (see #2128)
• Tests upgraded to Roslyn 3.8.0-3.final

UI Improvements

• Improve performance of Metadata DataGridCell (see #2151)
• Fix #2107: Add ScrollViewer around DisplaySettingsPanel
• Metadata: Improvements/fixes by @srutzky, see #2134, #2135, #2145, #2147 and #2153
• Updated Chinese translation

Bug fixes

• Fix #2129: be more flexible about the initialization order for the async state machine
• Fix #2140: ILSpy 6.2p1 no longer respects "use discards" setting
• Fix #2139: ArgumentOutOfRangeException for some xmldoc
• Fix #2039: Code generated by VB's On Error Resume Next causes "unassigned variable" compile errors
• Fix #2156: range syntax not being detected correctly in some cases
• BAML decompiler: #2109 and #2106
• Fix #2086: Check that window belongs to ILSpy before sending it a WM_COPYDATA message.
• Fix #2090: ignore mscorlib references without public key token, when trying to resolve mscorlib. This will automatically fallback to .NET 4.0's mscorlib.dll.
• #1292: Fix some more problems with pinned locals.
• Fix #1555: Eliminate value-type temporaries emitted by mcs on field reads.
• Fix #2056: "remove branch into body" must be executed before the clone cleanup
• Fix #2101: reset removeExtraLoad flag if keepAssignmentBefore is set; implement simple case-de-duplication: abort if there are any duplicate cases.
• Fix #2100: 'value'-named auto property could not be recognized correctly.
• Fix #1441: Decompose flags enum values starting from the value with the highest Hamming Weight (popcount).

New Language Features

• C# 9.0: function pointers (see #2150)
• C# 9.0: foreach with GetEnumerator extension methods

General

• Metadata: Improvements/fixes by @srutzky, see #2134, #2135, #2145, #2147 and #2153
• Improve performance of Metadata DataGridCell (see #2151)
• Updated Chinese translation (see #2160)
• Add option for string.Concat decompilation
• Tests upgraded to Roslyn 3.8.0-3.final

Bug fixes

• Fix #2129: be more flexible about the initialization order for the async state machine
• Fix #2140: ILSpy 6.2p1 no longer respects "use discards" setting
• Fix #2139: ArgumentOutOfRangeException for some xmldoc
• Fix #2039: Code generated by VB's On Error Resume Next causes "unassigned variable" compile errors
• Fix #2156: range syntax not being detected correctly in some cases
• BAML decompiler: #2109 and #2106

New Language Features

• C# 7.0: Deconstruction
• C# 8.0: await foreach
• C# 8.0: Disposable ref structs
• C# 8.0: Enhanced using statements
• C# 8.0: switch expressions
• C# 9.0: init accessors
• C# 9.0: Lambda parameter discards

General

• Add an option to enable aggressive inlining of expressions.
• Add an option to always qualify member references (by @Pathoschild, see #2114)
• ReadyToRun: Variable tracking in output (by @edkazcarlson, see #2067)
• ReadyToRun: Optimized debug info output (by @cshung, see #2113)
• Work on unifying the code formatting (see #2128)

UI Improvements

• Updated Chinese translation (by @maikebing, @Berrysoft, @yyjdelete, see #2066)
• Fix #2107: Add ScrollViewer around DisplaySettingsPanel

Bug fixes

• Fix #2086: Check that window belongs to ILSpy before sending it a WM_COPYDATA message.
• Fix #2090: ignore mscorlib references without public key token, when trying to resolve mscorlib. This will automatically fallback to .NET 4.0's mscorlib.dll.
• #1292: Fix some more problems with pinned locals.
• Fix #1555: Eliminate value-type temporaries emitted by mcs on field reads.
• Fix #2056: "remove branch into body" must be executed before the clone cleanup
• Fix #2101: reset removeExtraLoad flag if keepAssignmentBefore is set; implement simple case-de-duplication: abort if there are any duplicate cases.
• Fix #2100: 'value'-named auto property could not be recognized correctly.
• Fix #1441: Decompose flags enum values starting from the value with the highest Hamming Weight (popcount).
• And many other fixes, for a full list click here.

New Language Features

• C# 9.0: Native ints
• C# 9.0: Attributes on local functions

General

• ILSpy now uses System.Reflection.Metadata 1.8.1

UI Improvements

• Assembly List UX: double-click selects list and dismisses dialog
• Base types treenode: Create a flat list of nodes containing all base types instead of just the direct base types

Bug fixes

• Fix #2050: Ref local variable is inlined incorrectly, changing the exception behavior
• Fix #1903: un-inline argument of unsupported isinst instructions.
• Fix #2073: Ensure the startOffsetVar actually appears in the expected instruction, not somewhere else.
• Fix #2068: ILSpy can't find referenced library even though it's open
• And many other fixes, for a full list click here.

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