Merge pull request #2001 from OmniSharp/feature/scripting-lang-version

C# scripting should use language version "latest" by default

src/OmniSharp.Script/ScriptProjectProvider.cs

@@ -43,7 +43,7 @@ public class ScriptProjectProvider
             "System.Threading.Tasks"
         };
 
-        private static readonly CSharpParseOptions ParseOptions = new CSharpParseOptions(LanguageVersion.CSharp8, DocumentationMode.Parse, SourceCodeKind.Script);
+        private static readonly CSharpParseOptions ParseOptions = new CSharpParseOptions(LanguageVersion.Latest, DocumentationMode.Parse, SourceCodeKind.Script);
 
         private readonly Lazy<CSharpCompilationOptions> _compilationOptions;
         private readonly Lazy<CSharpCommandLineArguments> _commandLineArgs;
@@ -103,7 +103,6 @@ private CSharpCompilationOptions CreateCompilationOptions()
 
             compilationOptions = compilationOptions
                 .WithAllowUnsafe(true)
-
                 .WithMetadataReferenceResolver(metadataReferenceResolver)
                 .WithSourceReferenceResolver(sourceResolver)
                 .WithAssemblyIdentityComparer(DesktopAssemblyIdentityComparer.Default)

tests/OmniSharp.Script.Tests/ScriptProjectProviderTests.cs

@@ -0,0 +1,23 @@
+using System.IO;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.Scripting.Hosting;
+using Microsoft.Extensions.Logging;
+using OmniSharp.Services;
+using Xunit;
+
+namespace OmniSharp.Script.Tests
+{
+    public class ScriptProjectProviderTests
+    {
+        [Fact]
+        public void DefaultLanguageVersionShouldBeLatest()
+        {
+            var scriptProjectProvider = new ScriptProjectProvider(new ScriptOptions(), new OmniSharpEnvironment(), new LoggerFactory(), true, false);
+            var scriptProjectInfo = scriptProjectProvider.CreateProject("test.csx", Enumerable.Empty<MetadataReference>(), Path.GetTempPath(), typeof(CommandLineScriptGlobals));
+            Assert.Equal(LanguageVersion.Latest, ((CSharpParseOptions)scriptProjectInfo.ParseOptions).SpecifiedLanguageVersion);
+            Assert.Equal(LanguageVersion.CSharp9, ((CSharpParseOptions)scriptProjectInfo.ParseOptions).LanguageVersion);
+        }
+    }
+}

tests/OmniSharp.Script.Tests/WorkspaceInformationTests.cs

@@ -4,6 +4,7 @@
 using System.Linq;
 using System.Reflection;
 using System.Threading.Tasks;
+using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Scripting.Hosting;
 using OmniSharp.Models.FilesChanged;
 using OmniSharp.Models.WorkspaceInformation;