Upgrade language version fixer fails to update the correct program configuration

[gafter]

I have a project with the following source in it

public class Program
{
    public static void Main()
    {
        int x = default;
    }
}

The compiler complains

error CS8107: Feature 'default literal' is not available in C# 7.0. Please use language version 7.1 or greater.

control-. offers to update to language version 7.1 or latest. I accept its update to latest, but the error remains.

Looking at the project file, it updated the wrong section. My program configuration is "Debug|x86". But the updated project file is as it appears below. As you can see the language version has not been updated in the active configuration.

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="14.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
    <ProjectGuid>{F314717E-88C4-4B6D-B173-04E2F331C217}</ProjectGuid>
    <OutputType>Exe</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>CSharpSample1</RootNamespace>
    <AssemblyName>CSharpSample1</AssemblyName>
    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
    <FileAlignment>512</FileAlignment>
    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
    <TargetFrameworkProfile />
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
    <PlatformTarget>AnyCPU</PlatformTarget>
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DefineConstants>TRACE;__DEMO__</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <LangVersion>latest</LangVersion>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'">
    <DebugSymbols>true</DebugSymbols>
    <OutputPath>bin\x64\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <DebugType>full</DebugType>
    <PlatformTarget>x64</PlatformTarget>
    <ErrorReport>prompt</ErrorReport>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
    <Prefer32Bit>true</Prefer32Bit>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x64'">
    <OutputPath>bin\x64\Release\</OutputPath>
    <DefineConstants>TRACE;__DEMO__</DefineConstants>
    <Optimize>true</Optimize>
    <DebugType>pdbonly</DebugType>
    <PlatformTarget>x64</PlatformTarget>
    <ErrorReport>prompt</ErrorReport>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
    <Prefer32Bit>true</Prefer32Bit>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'">
    <DebugSymbols>true</DebugSymbols>
    <OutputPath>bin\x86\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <DebugType>full</DebugType>
    <PlatformTarget>x86</PlatformTarget>
    <ErrorReport>prompt</ErrorReport>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
    <Prefer32Bit>true</Prefer32Bit>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
    <OutputPath>bin\x86\Release\</OutputPath>
    <DefineConstants>TRACE;__DEMO__</DefineConstants>
    <Optimize>true</Optimize>
    <DebugType>pdbonly</DebugType>
    <PlatformTarget>x86</PlatformTarget>
    <ErrorReport>prompt</ErrorReport>
    <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
    <Prefer32Bit>true</Prefer32Bit>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Core" />
    <Reference Include="System.ValueTuple, Version=4.0.1.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51, processorArchitecture=MSIL">
      <HintPath>..\packages\System.ValueTuple.4.3.0\lib\netstandard1.0\System.ValueTuple.dll</HintPath>
      <Private>True</Private>
    </Reference>
    <Reference Include="System.Xml.Linq" />
    <Reference Include="System.Data.DataSetExtensions" />
    <Reference Include="Microsoft.CSharp" />
    <Reference Include="System.Data" />
    <Reference Include="System.Net.Http" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Benchmark.cs" />
    <Compile Include="Program.cs" />
    <Compile Include="Properties\AssemblyInfo.cs" />
    <Compile Include="ValueTuple.cs" />
  </ItemGroup>
  <ItemGroup>
    <None Include="App.config" />
    <None Include="packages.config" />
  </ItemGroup>
  <ItemGroup>
    <ProjectReference Include="..\VBLibrary\VBLibrary.vbproj">
      <Project>{549eefc8-a5e1-4366-a5d4-51910db84c32}</Project>
      <Name>VBLibrary</Name>
    </ProjectReference>
  </ItemGroup>
  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>

/cc @jcouv

[jcouv]

This is likely a problem in the project system layer. The code fix just sets CSharpProjectConfigurationProperties3.LanguageVersion.

The strange thing is I thought that API had the opposite problem, namely it would make too many insertions (producing verbose project XML files).

@gafter What version of VS are you using?

Tagging @davkean

[gafter]

This is using the daily preview

[davkean]

The project system should update whatever configuration you set CSharpProjectConfigurationProperties.LanguageVersion on @jcouv. Point me to the fixer?

[jcouv]

Here's the fixer: https://github.com/dotnet/roslyn/blob/master/src/Features/CSharp/Portable/UpgradeProject/CSharpUpgradeProjectCodeFixProvider.cs

The PR, for related files: #17435

[davkean]

I can reproduce this. Not an expert in DTE usage but usage looks correct; https://github.com/dotnet/roslyn/pull/17435/files#diff-cbb8610d7833d8bed4af13328decbaebR308.

I'll move it over to us.

[davkean]

This issue was moved to dotnet/project-system#2985

[Neme12]

This should be reopened because it was incorrectly moved, the problem is indeed on our side. See #25875 (comment)

[jcouv]

@Neme12 fixed this for dev16.1 preview1. Thanks!