When I build my first project it seems that Unreal Engine starts building UnrealBuildTool and at that time I got some error messages:
Android/UEBuildAndroid.cs(58,10): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Android/UEBuildAndroid.cs(63,10): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Android/AndroidToolChain.cs(17,11): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Android/AndroidToolChain.cs(18,11): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Android/AndroidToolChain.cs(86,75): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Android/AndroidToolChain.cs(86,117): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Configuration/TargetRules.cs(1929,10): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
Configuration/TargetRules.cs(1939,10): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/RulesAssembly.cs(25,11): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/RulesAssembly.cs(61,24): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/Plugins.cs(152,17): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/Plugins.cs(163,17): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/Plugins.cs(174,23): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/Plugins.cs(191,23): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/RulesCompiler.cs(172,18): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
System/RulesCompiler.cs(393,49): error CS0246: The type or namespace name `IReadOnlyList' could not be found. Are you missing an assembly reference?
But everything seems ok and project is built successfully. Do that will affect to anything later?
I use Ubuntu 16.04 and UE 4.17.1.