Language Feature Roadmap

Current language feature status of the master branch is detailed in #829. The following list shows all completed language versions.

C# 1

• XmlDoc (see also #163)
• switch(string) (see Switch tag as well)
• goto case -> #316
• params
• unsafe -> #924

C# 2 (VS 2005)

• Generics
• Partial types: These are not applicable in decompiled code, as the code is decompiled into exactly one part.
• Anonymous methods
• Iterators
• Nullable types -> Nullable<T>
• Getter/setter separate accessibility
• Method group conversions (delegates)
• Co- and Contra-variance for delegates and interfaces
• Static classes
• Delegate inference

C# 3 (VS 2008)

• Implicitly typed local variables
• Object and collection initializers
• Auto-Implemented properties
• Anonymous types
• Extension methods
• Query expressions
• Lambda expression
• Expression trees
• Partial methods: These are not applicable in decompiled code, as the code is decompiled into exactly one part.

C# 4 (VS 2010)

• Dynamic binding -> #154
• Named arguments -> #950
• Optional arguments -> #1083
• Generic co- and contravariance
• Embedded interop types ("NoPIA"): TODO

C# 5 (VS 2012)

• Asynchronous methods
• Caller info attributes: In general it's not possible to remove the compiler-generated values, because that would require us to produce the exact original source code, which is impossible.

C# 6 (VS 2015)

• Compiler-as-a-service (Roslyn)
• Import of static type members into namespace: Currently, there are no plans to emit using static declarations.
• Exception filters (see #761)
• Await in catch/finally blocks
• Auto property initializers
• Default values for getter-only properties
• Expression-bodied members
• Null propagator (null-conditional operator, succinct null checking)
• String interpolation (see #1012)
• nameof operator
• Dictionary initializer
• Allow 'Add' extension methods in collection initializers

C# 7.0 (Visual Studio 2017)

• Out variables
• Pattern matching --> #2048
• Tuples --> #1134
• Deconstruction --> #1832
• Discards
• Local Functions
• Binary Literals
• Digit Separators
• Ref returns and locals
• Generalized async return types
• More expression-bodied members
• Throw expressions

C# 7.1 (Visual Studio 2017 version 15.3)

• Async main --> #1023
• Default expressions
• Reference assemblies
• Inferred tuple element names
• Pattern-matching with generics

C# 7.2 (Visual Studio 2017 version 15.4)

• ref readonly
• interior pointer/Span/ref struct
• non-trailing named arguments
• private protected (see #1010)
• conditional ref operator
• Digit separator after base specifier

C# 7.3 (Visual Studio 2017 version 15.7)

• System.Enum, System.Delegate and unmanaged constraints.
• Ref local re-assignment: Ref locals and ref parameters can now be reassigned with the ref assignment operator (= ref).
• Stackalloc initializers: Stack-allocated arrays can now be initialized, for example Span<int> x = stackalloc[] { 1, 2, 3 };.
• Indexing movable fixed buffers: Fixed buffers can be indexed into without first being pinned.
• Custom fixed statement: Types that implement a suitable GetPinnableReference can be used in a fixed statement.
• Improved overload candidates: Some overload resolution candidates can be ruled out early, thus reducing ambiguities.
• Expression variables in initializers and queries: Expression variables like out var and pattern variables are allowed in field initializers, constructor initializers, and LINQ queries.
• Tuple comparison: Tuples can now be compared with == and !=. -> #1822
• Attributes on backing fields: Allows [field: …] attributes on an auto-implemented property to target its backing field.

C# 8.0 (Visual Studio 2019)

• Default Interface Methods
• Async streams
• await foreach
• Nullable reference type
• Readonly members
• Recursive patterns
• Switch expressions
• Enhanced using (using var ... = ...;)
• await using
• Disposable ref struct
• Ranges
• Null-coalescing Assignment
• Alternative interpolated verbatim strings
• stackalloc in nested contexts
• Unmanaged generic structs
• Static local functions

C# 9 (VS 2019 16.8)

• Target-typed new
• Skip locals init
• Lambda discard parameters
• Native ints
• Attributes on local functions
• Function pointers
• Pattern matching improvements
• Static lambdas
• Records -> #2217
• Target-typed conditional
• Covariant Returns --> #2470
• Extension GetEnumerator
• Module initializers
• Extending Partial
• Top-level statements

C# 10 (VS 2022 17.0)

• Record structs
• Global Using Directive
• Improved Definite Assignment
• Constant Interpolated Strings
• Extended property patterns
• Sealed record ToString
• Source Generator V2 APIs
• Mix declarations and variables in deconstruction
• Async method builder override
• Enhanced #line directive
• Lambda improvements
• Static Abstract Members In Interfaces C# 10 Preview
• Interpolated string improvements
• File-scoped namespace
• Parameterless struct constructors
• Caller expression attribute