Dealing with Different Language Versions
As programming languages evolve, it is only natural to improve your code with new language features. On the other hand, there may be factors that prevent you from upgrading to the newest language version.
ReSharper is aware of different language versions. It analyzes code and applies its own features according to the current language version. Language version is detected automatically for each language, but you can set version manually for some of the languages as described below.
ReSharper 2017.3 fully supports all C# versions up to C# 6.0 and partially C# 7.0. By default, ReSharper automatically detects C# version based on the associated compiler. However, you can specify the target C# version explicitly by selecting the project in the Solution Explorer and using the C# Language Level property in the Visual Studio's Properties window (choose in the menu).
ReSharper 2017.3 fully supports all VB.NET versions up to VB 14 and partially VB 15. By default, ReSharper automatically detects VB.NET version based on the associated compiler. However, you can specify the target VB.NET version explicitly by selecting the project in the Solution Explorer and using the VB.NET Language Level property in the Visual Studio's Properties window (choose in the menu).
ReSharper 2017.3 fully supports all TypeScript versions up to 2.0. ReSharper automatically detects TypeScript version by the
<TypeScriptToolsVersion> property in the Visual Studio project file. But you can specify the target TypeScript version explicitly using the TypeScript language level selector on the page of ReSharper options.
ReSharper 2017.3 supports C, C++03, and partially C++11, C++14, C++17. ReSharper detects C++ version automatically based on the platform toolset (/std switch.in the project properties) and/or on the
ReSharper supports CSS up to version 4.0. In practical terms, CSS version is by far less important than CSS feature set supported by different web browsers. Therefore, ReSharper lets you tune its CSS code inspection for specific versions of particular web browsers. You can configure it on the options page.