Mono.CSharp uses the MSFT Reflection.Emit namespace to write its asse…

…mblies, whereas the compiler in the Mono distro uses the IKVM reimplementations. There is a difference in behaviour in that the module MVId read from the Builder into the .mdb file is not the one written to the assembly in the Reflection.Emit case, leading to a symbol read failure due to mismatched GUID values.

Fix by updating the GUID in the .mdb from the .exe we generated, so we can have a sort-of Mono test in the CI build

Build/build.fsx

@@ -264,6 +264,13 @@ Target "BuildMonoSamples" (fun _ ->
                                           info.WorkingDirectory <- "."
                                           info.Arguments <- (@"-debug -out:./_Mono/Sample1/Sample1.exe  .\Sample1\Program.cs")) (TimeSpan.FromMinutes 5.0)
     if result <> 0 then failwith "Mono compilation failed"
+
+    // Fix up symbol file to have the MVId emitted by the System.Reflection.Emit code
+    let assembly = System.Reflection.Assembly.ReflectionOnlyLoadFrom (FullName "./_Mono/Sample1/Sample1.exe")
+    let mvid = assembly.ManifestModule.ModuleVersionId.ToByteArray();
+    let symbols = System.IO.File.ReadAllBytes("./_Mono/Sample1/Sample1.exe.mdb")
+    mvid|> Array.iteri (fun i x -> symbols.[i+16] <- x)
+    System.IO.File.WriteAllBytes("./_Mono/Sample1/Sample1.exe.mdb", symbols)
 )
 
 let SimpleInstrumentingRun (samplePath:string) (binaryPath:string) (reportSigil:string) =

MCS/MCS.fsproj

@@ -1,6 +1,5 @@
 <?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>
@@ -56,7 +55,7 @@
       </PropertyGroup>
     </Otherwise>
   </Choose>
-  <Import Project="$(FSharpTargetsPath)" />
+  <Import Project="$(FSharpTargetsPath)" Condition="Exists('$(FSharpTargetsPath)')" />
   <ItemGroup>
     <Compile Include="AssemblyInfo.fs" />
     <Compile Include="..\_Generated\AssemblyVersion.fs">