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).