Specify C# 5 as the language version used in all projects.

Attempts to use features from a new version will generate compile errors (on Roslyn and possibly other compilers), preventing accidental adoption of new language features.

OpenRA.Game/OpenRA.Game.csproj

@@ -43,6 +43,7 @@
     <UseVSHostingProcess>false</UseVSHostingProcess>
     <StartArguments>Game.Mod=ra</StartArguments>
     <Commandlineparameters>Game.Mod=ra</Commandlineparameters>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>

OpenRA.Mods.Cnc/OpenRA.Mods.Cnc.csproj

@@ -41,6 +41,7 @@
     <OutputPath>bin\Debug\</OutputPath>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>
@@ -213,4 +214,4 @@
     <Message Text="DEBUG TargetName:             $(TargetName)"/>
     -->
   </Target>
-</Project>
+</Project>

OpenRA.Mods.Common/OpenRA.Mods.Common.csproj

@@ -24,6 +24,7 @@
     <PlatformTarget>x86</PlatformTarget>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>
@@ -859,4 +860,4 @@
     <Message Text="DEBUG TargetName:             $(TargetName)"/>
     -->
   </Target>
-</Project>
+</Project>

OpenRA.Mods.D2k/OpenRA.Mods.D2k.csproj

@@ -42,6 +42,7 @@
     <DefineConstants>TRACE;DEBUG;</DefineConstants>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>
@@ -144,4 +145,4 @@
     <Message Text="DEBUG TargetName:             $(TargetName)"/>
     -->
   </Target>
-</Project>
+</Project>

OpenRA.Platforms.Default/OpenRA.Platforms.Default.csproj

@@ -20,6 +20,7 @@
     <ErrorReport>prompt</ErrorReport>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>

OpenRA.Server/OpenRA.Server.csproj

@@ -42,6 +42,7 @@
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
     <PlatformTarget>x86</PlatformTarget>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>

OpenRA.StyleCheck/OpenRA.StyleCheck.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -19,6 +19,7 @@
     <WarningLevel>4</WarningLevel>
     <ExternalConsole>true</ExternalConsole>
     <PlatformTarget>x86</PlatformTarget>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x86' ">
     <Optimize>true</Optimize>

OpenRA.Test/OpenRA.Test.csproj

@@ -20,6 +20,7 @@
     <PlatformTarget>x86</PlatformTarget>
     <ErrorReport>prompt</ErrorReport>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>

OpenRA.Utility/OpenRA.Utility.csproj

@@ -42,6 +42,7 @@
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
     <PlatformTarget>x86</PlatformTarget>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <LangVersion>5</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <DebugSymbols>true</DebugSymbols>