[gh-139] Potential fix for value tuples.

source/Server/Compilation/Internal/NetFrameworkRuntime.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Reflection;
+
+namespace SharpLab.Server.Compilation.Internal {
+    public static class NetFrameworkRuntime {
+        private static readonly Assembly Mscorlib = typeof(object).Assembly;
+
+        public static Assembly AssemblyOfValueTuple { get; }
+            = Mscorlib.GetType(typeof(ValueTuple).FullName) != null ? Mscorlib : typeof(ValueTuple).Assembly;
+    }
+}

source/Server/Compilation/Setups/CSharpSetup.cs

@@ -28,7 +28,7 @@ namespace SharpLab.Server.Compilation.Setups {
             _references = referenceCollector.SlowGetMetadataReferencesRecursive(
                 // Essential
                 typeof(Binder).Assembly,
-                typeof(ValueTuple<>).Assembly,
+                NetFrameworkRuntime.AssemblyOfValueTuple,
 
                 // Runtime
                 typeof(JitGenericAttribute).Assembly,

source/Server/Compilation/Setups/VisualBasicSetup.cs

@@ -32,7 +32,7 @@ namespace SharpLab.Server.Compilation.Setups {
                 o.ParseOptions = new VisualBasicParseOptions(maxLanguageVersion).WithFeatures(features);
                 o.MetadataReferences = _referenceCollector.SlowGetMetadataReferencesRecursive(
                     typeof(StandardModuleAttribute).Assembly,
-                    typeof(ValueTuple<>).Assembly,
+                    NetFrameworkRuntime.AssemblyOfValueTuple,
                     typeof(JitGenericAttribute).Assembly
                 ).ToImmutableList();
             });

source/Tests/DecompilationTests.cs

@@ -23,6 +23,18 @@ namespace SharpLab.Tests {
             _output = output;
         }
 
+        [Theory]
+        // Tuples, https://github.com/ashmind/SharpLab/issues/139
+        [InlineData("class C { void M((int, string) t) {} }")]
+        public async Task SlowUpdate_DecompilesSimpleCodeWithoutErrors(string code) {
+            var driver = MirrorSharpTestDriver.New().SetText(code);
+
+            var result = await driver.SendSlowUpdateAsync<string>();
+            var errors = result.JoinErrors();
+
+            Assert.True(errors.IsNullOrEmpty(), errors);
+        }
+
         [Theory]
         [InlineData("Constructor.BaseCall.cs2cs")]
         [InlineData("NullPropagation.ToTernary.cs2cs")]