[Fact]
        public void NonNullTypesAttribute_Injected_InCSharp7()
        {
            var comp = CreateCompilation(NonNullTypesTrue, parseOptions: TestOptions.Regular7);
         
            // PROTOTYPE(NullableReferenceTypes): CSharpCompilation.AbstractSymbolSearcher needs to inject namespaces and types too
            //Assert.True(comp.ContainsSymbolsWithName("NonNullTypesAttribute", SymbolFilter.Type));
            //Assert.Equal("System.Runtime.CompilerServices.NonNullTypesAttribute", comp.GetSymbolsWithName("NonNullTypesAttribute", SymbolFilter.Type).Single().ToTestDisplayString());
            //Assert.Equal("System.Runtime.CompilerServices.NonNullTypesAttribute", comp.GetSymbolsWithName(n => n == "NonNullTypesAttribute", SymbolFilter.Type).Single().ToTestDisplayString());

            //Assert.True(comp.ContainsSymbolsWithName("EmbeddedAttribute", SymbolFilter.Type));
            //Assert.Equal("Microsoft.CodeAnalysis.EmbeddedAttribute", comp.GetSymbolsWithName("EmbeddedAttribute", SymbolFilter.Type).Single().ToTestDisplayString());
            //Assert.Equal("Microsoft.CodeAnalysis.EmbeddedAttribute", comp.GetSymbolsWithName(n => n == "EmbeddedAttribute", SymbolFilter.Type).Single().ToTestDisplayString());

        }