A tool to update the Roslyn compiler and C# language versions for a Unity installation.

Installation

NOTE: This will modify your Unity installation folder, administrative privileges are required!

Interactive Mode

Launch the tool directly to interactively select a Unity editor version to patch.

Command Line (Advanced) Mode

Pass the Unity editor path to UnityRoslynUpdater.exe:

UnityRoslynUpdater.exe <path to Unity Editor folder>

For example: UnityRoslynUpdater.exe "C:\Program Files\Unity\Hub\Editor\2022.3.8f1\Editor"

Usage

After updating the Roslyn compiler, newer C# language versions are available but not enabled by default. To enable them, you must explicitly opt in for each assembly definition in your project.

Create a csc.rsp file in the same directory as your assembly definition (.asmdef) file with the following content (replace 14 with your desired language version):

-langversion:14

NOTE: Version 2.0.24 or later of the com.unity.ide.visualstudio package is required for the language version specified in csc.rsp to be reflected in the generated .csproj files.

Language Support

• Working
  • Feature works exactly as expected.
• PolySharp
  • Feature works when using PolySharp and/or manually implementing missing APIs.
• Not Supported
  • Requires runtime features or BCL changes that Unity does not have. Attempting to use the feature may result in compiler errors.
• Crash
  • Requires runtime features that Unity does not have. Attempting to use the feature may compile, but will result in crashes.

C# 14

Feature	Status
Extension members	Working
Null-conditional assignment	Working
nameof supports unbound generic types	Working
More implicit conversions for Span<T> and ReadOnlySpan<T>	Working
Modifiers on simple lambda parameters	Working
field backed properties	Working
partial events and constructors	Working

C# 13

Feature	Status
params collections	Working
New lock type and semantics	Not Supported
New escape sequence - \e	Working
Method group natural type improvements	Working
Implicit indexer access in object initializers	Working
Enable ref locals and unsafe contexts in iterators and async methods	Working
Enable ref struct types to implement interfaces	Not Supported
Allow ref struct types as arguments for type parameters in generics	Not Supported
Partial properties and indexers	Working
Overload resolution priority	PolySharp
field backed properties	Working

C# 12

Feature	Status
Primary constructors	Working
Optional parameters in lambda expressions	Working
Alias any type	Working
Inline arrays	Not Supported
Collection expressions	Working
Interceptors	Not Supported

C# 11

Feature	Status
Raw string literals	Working
static abstract/static virtual members in interfaces	Not Supported
Checked user defined operators	Working
Relaxed shift operators	Working
Unsigned right-shift operator	Working
Generic attributes	Crash
UTF-8 string literals	Working
Newlines in string interpolations	Working
List patterns	Working
File-local types	Working
Required members	PolySharp
Auto-default structs	Working
Pattern match Span<char> or ReadOnlySpan<char> on a constant string	Working
Extended nameof scope	Working
Numeric IntPtr and UIntPtr	Working
ref fields	Not Supported
ref scoped variables	PolySharp
Improved method group conversion to delegate	Working

C# 10

Feature	Status
Record structs	Working
Improvements of structure types	Working
Interpolated string handler	PolySharp
Global using directives	Working
File-scoped namespace declaration	Working1
Extended property patterns	Working
Lambda expression improvements	Working
Constant interpolated strings	Working
Record types can seal ToString	Working
Assignment and declaration in same deconstruction	Working
Improved definite assignment	Working
Allow AsyncMethodBuilder attribute on methods	Not Supported2
CallerArgumentExpression attribute	PolySharp
Enhanced #line pragma	Working

1. Unity 2021 and earlier require UnityNamespacePatch to be installed.
2. AsyncMethodBuilderAttribute requires changes to its [AttributeUsage] attribute for this to work.