Getting "Unreachable code detected warning" when using #if preprocessor directive

[mattstewart1189]

Environment data

dotnet --info output:
.NET Command Line Tools (2.1.200)

Product Information:
Version: 2.1.200
Commit SHA-1 hash: 2edba8d7f1

_Runtime Environment:
OS Name: Windows
OS Version: 10.0.15063
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\2.1.200_

Microsoft .NET Core Shared Framework Host
Version : 2.0.7
Build : 2d61d0b043915bc948ebf98836fefe9ba942be11

VS Code version:
1.23.1
d0182c3417d225529c6d5ad24b7572815d0de9ac
x64

C# Extension version:
1.15.2

Steps to reproduce

Rethrow an exception in a catch block wrapped in an if preprocessor directive.

            catch (Exception ex)
            {
#if DEBUG
                throw ex;
#endif
               //this line gives "Unreachable code detected" warning
                Console.WriteLine($"An unhandeled exception has occured. {ex.Message}");
                Console.ReadKey();
            }

Expected behavior

I would think that no "Unreachable code detected" warning should be given in this case. But the compiler seems to give this error as well?

Actual behavior

Code after the rethrow will give an "Unreachable code detected" warning.

[DustinCampbell]

This is likely by design. Your project will be loaded with its default configuration, which is usually "Debug". So, the "throw ex;" statement would be included, which means that the code afterward is unreachable.