C# 7.3–13 + .NET Framework 4.8.1 + Roslyn

[Kiquenet]

stack: solution sln + NET Frk 4.8.1 + few csproj NET Frk 4.5 + Visual Studio 202 + Azure Devops
C# 7.3–12 in .NET Framework 4.8.1 use Roslyn ?

Can a .NET Framework 4.8 website use C# 7 features without bundling Roslyn?
https://stackoverflow.com/questions/76093222/can-a-net-framework-4-8-website-use-c-sharp-7-features-without-bundling-roslyn

.NET compiler platform package version reference
4.14.0 Visual Studio 2022 version 17.14
https://learn.microsoft.com/en-us/visualstudio/extensibility/roslyn-version-support?view=visualstudio

Does C# 8 Support .NET Framework? Exploring Visual Studio 2019 Build Settings Compatibility
https://www.codestudy.net/blog/does-c-8-support-the-net-framework/

Questions about the roslyn version
https://github.com/dotnet/roslyn/discussions/50395

<LangVersion>7.3</LangVersion>
or
<LangVersion>latest</LangVersion>

<PackageReference Include=“Microsoft.Net.Compilers” Version=“4.12.0” PrivateAssets=“all” />

.editorconfig o Directory.Build.props
dotnet_language_version = 7.3

❌ **C# 8.0

• using var (Using declarations)
• await using
• Switch expressions
• ?? = null‑coalescing assignment
• Pattern matching avanzado
• static local functions
• Nullable Reference Types (string?)

runtime (NO .NET Framework)

• Default Interface Methods
• Ranges & Indices (^1, 1..3)
• Async Streams (await foreach)

❌ C# 9.0

• Records
• Init‑only properties (init;)
• Top‑level statements
• Target‑typed new()

❌ C# 10.0

• File‑scoped namespaces
• Global usings
• Record structs
• sealed + ToString improvements de records
• λ

❌ C# 11 (VS2022 / .NET 7)

• required members
• Generic attributes
• Raw string literals (""" ... """)
• List patterns ([a, .., b])

❌ C# 12 (.NET 8/9)

• Primary constructors en clases
• Collection expressions ([1, 2, 3])
• Alias de operadores (operator "add")

❌ C# 13 (VS2026 / .NET 10)