diff --git a/FSharp.sln b/FSharp.sln
index 0d41f990d73..9a3f8f5e6ff 100644
--- a/FSharp.sln
+++ b/FSharp.sln
@@ -31,7 +31,7 @@ Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Tests.FSharpSuite",
 EndProject
 Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Compiler.UnitTests", "tests\FSharp.Compiler.UnitTests\FSharp.Compiler.UnitTests.fsproj", "{A8D9641A-9170-4CF4-8FE0-6DB8C134E1B5}"
 EndProject
-Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Core.UnitTests", "tests\FSharp.Core.UnitTests\FSharp.Core.UnitTests.fsproj", "{88E2D422-6852-46E3-A740-83E391DC7973}"
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "FSharp.Core.UnitTests", "tests\FSharp.Core.UnitTests\FSharp.Core.Unittests.fsproj", "{88E2D422-6852-46E3-A740-83E391DC7973}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Compiler", "Compiler", "{3881429D-A97A-49EB-B7AE-A82BA5FE9C77}"
 EndProject
diff --git a/Makefile b/Makefile
index d955b9e7580..b392dfe356f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 include $(topsrcdir)mono/config.make
 
-.PHONY: restore
+.PHONY: restore build
 
 restore:
 	MONO_ENV_OPTIONS=$(monoopts) mono .nuget/NuGet.exe restore packages.config -PackagesDirectory packages -ConfigFile .nuget/NuGet.Config
@@ -27,7 +27,7 @@ build:
 	MONO_ENV_OPTIONS=$(monoopts) $(MSBUILD) /p:Configuration=$(Configuration) /p:TargetDotnetProfile=net40 src/fsharp/FSharp.Compiler.Server.Shared/FSharp.Compiler.Server.Shared.fsproj
 	MONO_ENV_OPTIONS=$(monoopts) $(MSBUILD) /p:Configuration=$(Configuration) /p:TargetDotnetProfile=net40 src/fsharp/fsi/Fsi.fsproj
 	MONO_ENV_OPTIONS=$(monoopts) $(MSBUILD) /p:Configuration=$(Configuration) /p:TargetDotnetProfile=net40 src/fsharp/fsiAnyCpu/FsiAnyCPU.fsproj
-	MONO_ENV_OPTIONS=$(monoopts) $(MSBUILD) /p:Configuration=$(Configuration) /p:TargetDotnetProfile=net40 tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj
+	MONO_ENV_OPTIONS=$(monoopts) $(MSBUILD) /p:Configuration=$(Configuration) /p:TargetDotnetProfile=net40 tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj
 	mkdir -p $(Configuration)/fsharp30/net40/bin
 	mkdir -p $(Configuration)/fsharp31/net40/bin
 	mkdir -p $(Configuration)/fsharp40/net40/bin
diff --git a/before_install.sh b/before_install.sh
index d1498a55e64..10f623a6b0d 100755
--- a/before_install.sh
+++ b/before_install.sh
@@ -32,7 +32,7 @@ fi
 # We need to run the command twice -- on some systems (e.g. macOS) the certs are installed in the user store,
 # and on other systems (e.g., Ubuntu) they're installed to the machine store. certmgr only shows what's in
 # the selected store, which is why we need to check both.
-if [ "$(certmgr -list -c Trust | grep -c -F "X.509")" -le 1 ] && [ "$(certmgr -list -c -m Trust | grep -c -F "X.509")" -le 1 ]; then
+if [ $OS = 'Linux' ] && [ "$(certmgr -list -c Trust | grep -c -F "X.509")" -le 1 ] && [ "$(certmgr -list -c -m Trust | grep -c -F "X.509")" -le 1 ]; then
   echo "No SSL certificates installed so unable to restore NuGet packages." >&2;
   echo "Run 'mozroots --sync --import' to install certificates to Mono's certificate store." >&2;
   exit 1
diff --git a/build-everything.proj b/build-everything.proj
index f236cde62cb..0d0cdea76c2 100644
--- a/build-everything.proj
+++ b/build-everything.proj
@@ -54,12 +54,12 @@
   <!-- +++++++++++++++++++++++ Project selection for testing +++++++++++++++++++++++++++++++ -->
 
   <ItemGroup Condition="'$(TEST_NET40_COREUNIT_SUITE)'=='1'" >
-    <ProjectsWithNet40 Include="tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj"/>
+    <ProjectsWithNet40 Include="tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj"/>
     <ProjectsWithNet40 Include="tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj"/>
   </ItemGroup>
 
   <ItemGroup Condition="'$(TEST_CORECLR_COREUNIT_SUITE)'=='1'">
-    <ProjectsWithCoreClr Include="tests/FSharp.Core.UnitTests/FSharp.Core.UnitTests.fsproj"/>
+    <ProjectsWithCoreClr Include="tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj"/>
     <ProjectsWithCoreClr Include="tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj"/>
   </ItemGroup>
 
diff --git a/build.sh b/build.sh
index 2d15c1a934e..7c4c450c838 100755
--- a/build.sh
+++ b/build.sh
@@ -24,12 +24,11 @@ Build and run a subset of test suites
 
 Usage:
 
-build.sh ^<all^|net40^|coreclr^|pcls^|vs^>
+build.sh ^<all^|net40^|coreclr^>
          ^<proto^|protofx^>
-         ^<ci^|ci_part1^|ci_part2^|ci_part3^|microbuild^>
          ^<debug^|release^>
          ^<diag^|publicsign^>
-         ^<test^|no-test^|test-net40-coreunit^|test-coreclr-coreunit^|test-compiler-unit^|test-pcl-coreunit^|test-net40-fsharp^|test-coreclr-fsharp^|test-net40-fsharpqa^>
+         ^<test^|no-test^|test-net40-coreunit^|test-coreclr-coreunit^|test-compiler-unit^|test-net40-fsharp^|test-coreclr-fsharp^>
          ^<include tag^>
          ^<init^>
 
@@ -41,15 +40,11 @@ Other examples:
 
     build.sh net40            (build compiler for .NET Framework)
     build.sh coreclr          (build compiler for .NET Core)
-    build.sh vs               (build Visual Studio IDE Tools)
     build.sh all              (build everything)
     build.sh test             (build and test default targets)
     build.sh net40 test       (build and test net40)
     build.sh coreclr test     (build and test net40)
-    build.sh vs test          (build and test net40)
     build.sh all test         (build and test net40)
-    build.sh nobuild test include Conformance (run only tests marked with Conformance category)
-    build.sh nobuild test include Expensive (run only tests marked with Expensive category)
 
 "
 
@@ -84,8 +79,6 @@ export BUILD_PHASE=1
 export BUILD_NET40_FSHARP_CORE=0
 export BUILD_NET40=0
 export BUILD_CORECLR=0
-export BUILD_PORTABLE=0
-export BUILD_VS=0
 export BUILD_CONFIG=release
 export BUILD_CONFIG_LOWERCASE=release
 export BUILD_DIAG=
@@ -94,11 +87,8 @@ export BUILD_PUBLICSIGN=0
 export TEST_NET40_COMPILERUNIT_SUITE=0
 export TEST_NET40_COREUNIT_SUITE=0
 export TEST_NET40_FSHARP_SUITE=0
-export TEST_NET40_FSHARPQA_SUITE=0
 export TEST_CORECLR_COREUNIT_SUITE=0
 export TEST_CORECLR_FSHARP_SUITE=0
-export TEST_PORTABLE_COREUNIT_SUITE=0
-export TEST_VS_IDEUNIT_SUITE=0
 export INCLUDE_TEST_SPEC_NUNIT=
 export INCLUDE_TEST_TAGS=
 
@@ -123,19 +113,6 @@ do
             export BUILD_PROTO_WITH_CORECLR_LKG=1
             export BUILD_CORECLR=1
             ;;
-        "pcls")
-            _autoselect=0
-            export BUILD_PORTABLE=1
-            ;;
-        "vs")
-            _autoselect=0
-            export BUILD_NET40=1
-            export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_VS=1
-            ;;
-        "vstest")
-            export TEST_VS_IDEUNIT_SUITE=1
-            ;;
         "nobuild")
             export BUILD_PHASE=0
             ;;
@@ -151,88 +128,11 @@ do
             export BUILD_NET40=1
             export BUILD_NET40_FSHARP_CORE=1
             export BUILD_CORECLR=1
-            export BUILD_PORTABLE=1
-            export BUILD_VS=1
-            export BUILD_SETUP=$FSC_BUILD_SETUP
-            export CI=1
-            ;;
-        "microbuild")
-            _autoselect=0
-            export BUILD_PROTO=1
-            export BUILD_NET40=1
-            export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_PROTO_WITH_CORECLR_LKG=1
-            export BUILD_CORECLR=1
-            export BUILD_PORTABLE=1
             export BUILD_VS=1
             export BUILD_SETUP=$FSC_BUILD_SETUP
-
-            export TEST_NET40_COMPILERUNIT_SUITE=1
-            export TEST_NET40_COREUNIT_SUITE=1
-            export TEST_NET40_FSHARP_SUITE=1
-            export TEST_NET40_FSHARPQA_SUITE=1
-            export TEST_CORECLR_COREUNIT_SUITE=0
-            export TEST_CORECLR_FSHARP_SUITE=0
-            export TEST_PORTABLE_COREUNIT_SUITE=1
-            export TEST_VS_IDEUNIT_SUITE=1
-            export CI=1
-            ;;
-
-        # These divide 'ci' into multiple chunks which can be done in parallel
-        "ci_part1")
-            _autoselect=0
-
-            # what we do
-            export BUILD_PROTO=1
-            export BUILD_NET40=1
-            export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_PORTABLE=1
-            export BUILD_VS=1
-            export BUILD_SETUP=$FSC_BUILD_SETUP
-            export TEST_NET40_COMPILERUNIT_SUITE=1
-            export TEST_NET40_FSHARPQA_SUITE=1
-            export TEST_VS_IDEUNIT_SUITE=1
-            export CI=1
-            ;;
-        "ci_part2")
-            _autoselect=0
-
-            # what we do
-            export BUILD_PROTO_WITH_CORECLR_LKG=1
-            export BUILD_PROTO=1
-            export BUILD_NET40=1
-            export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_PORTABLE=1
-
-            export TEST_NET40_COREUNIT_SUITE=1
-            export TEST_NET40_FSHARP_SUITE=1
-            export TEST_PORTABLE_COREUNIT_SUITE=1
-            export CI=1
-            ;;
-        "ci_part3")
-            _autoselect=0
-
-            # what we do
-            export BUILD_PROTO_WITH_CORECLR_LKG=1
-            export BUILD_PROTO=1
-            export BUILD_NET40=1
-            export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_CORECLR=1
-
-            export TEST_CORECLR_FSHARP_SUITE=1
-            export TEST_CORECLR_COREUNIT_SUITE=1
             export CI=1
             ;;
 
-        # TEMP: The Jenkins builds currently call this script with the 'ci' target,
-        #       but that doesn't exist even in build.cmd. It wasn't doing anything
-        #       before anyway, so accept 'ci' but ignore it for now because the test
-        #       suites don't build correctly on Linux/macOS yet anyway.
-        "ci")
-            # TODO: Do everything from ci_part1-3 here.
-            printf "The 'ci' target is currently ignored, until the test suite builds can be fixed for Linux/macOS.\n"
-            ;;
-
         "proto")
             export BUILD_PROTO=1            
             ;;
@@ -254,12 +154,6 @@ do
         "no-test")
             no_test=1
             ;;
-        "include")
-            failwith "The 'include' option is not (yet) supported by this script."
-            #export /a counter=!counter!+1
-            #if '$INCLUDE_TEST_SPEC_NUNIT' == '' ( export INCLUDE_TEST_SPEC_NUNIT=cat == $ARG2 ) else (set INCLUDE_TEST_SPEC_NUNIT=cat == $ARG2 or $INCLUDE_TEST_SPEC_NUNIT )
-            #if '$INCLUDE_TEST_TAGS' == '' ( export INCLUDE_TEST_TAGS=$ARG2 ) else (set INCLUDE_TEST_TAGS=$ARG2;$INCLUDE_TEST_TAGS )
-            ;;
         "test-all")
             _autoselect=0
             export BUILD_PROTO=1
@@ -267,23 +161,12 @@ do
             export BUILD_NET40=1
             export BUILD_NET40_FSHARP_CORE=1
             export BUILD_CORECLR=1
-            export BUILD_PORTABLE=1
-            export BUILD_VS=1
             export BUILD_SETUP=$FSC_BUILD_SETUP
 
             export TEST_NET40_COMPILERUNIT_SUITE=1
             export TEST_NET40_COREUNIT_SUITE=1
             export TEST_NET40_FSHARP_SUITE=1
-            export TEST_NET40_FSHARPQA_SUITE=1
-            export TEST_PORTABLE_COREUNIT_SUITE=1
             export TEST_CORECLR_COREUNIT_SUITE=1
-            export TEST_VS_IDEUNIT_SUITE=1
-            ;;
-        "test-net40-fsharpqa")
-            export BUILD_NET40=1
-            export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_PORTABLE=1
-            export TEST_NET40_FSHARPQA_SUITE=1
             ;;
         "test-compiler-unit")
             export BUILD_NET40=1
@@ -299,14 +182,9 @@ do
             export BUILD_CORECLR=1
             export TEST_CORECLR_COREUNIT_SUITE=1
             ;;
-        "test-pcl-coreunit")
-            export BUILD_PORTABLE=1
-            export TEST_PORTABLE_COREUNIT_SUITE=1
-            ;;
         "test-net40-fsharp")
             export BUILD_NET40=1
             export BUILD_NET40_FSHARP_CORE=1
-            export BUILD_PORTABLE=1
             export TEST_NET40_FSHARP_SUITE=1
             ;;
         "test-coreclr-fsharp")
@@ -329,50 +207,43 @@ do
     esac
 done
 
-if [ $_buildexit -eq 1 ]; then
+if [ "$_buildexit" = "1" ]; then
     exit $_buildexitvalue
 fi
 
 # Apply defaults, if necessary.
-if [ $_autoselect -eq 1 ]; then
+if [ "$_autoselect" = "1" ]; then
     export BUILD_NET40=1
     export BUILD_NET40_FSHARP_CORE=1
 fi
 
-if [ $_autoselect_tests -eq 1 ]; then
-    if [ $BUILD_NET40 -eq 1 ]; then
+if [ "$_autoselect_tests" = "1" ]; then
+    if [ "$BUILD_NET40" = "1" ]; then
         export TEST_NET40_COMPILERUNIT_SUITE=1
-        export TEST_NET40_COREUNIT_SUITE=1
-        export TEST_NET40_FSHARP_SUITE=1
-        export TEST_NET40_FSHARPQA_SUITE=1
+        
+        # This requires a build of FSharp.Core.dll?
+        # export TEST_NET40_COREUNIT_SUITE=1
+        
+        # This requires a lot more work to get running on OSX/Linux
+        # export TEST_NET40_FSHARP_SUITE=1
     fi
 
-    if [ $BUILD_CORECLR -eq 1 ]; then
+    if [ "$BUILD_CORECLR" = "1" ]; then
         export BUILD_NET40=1
         export BUILD_NET40_FSHARP_CORE=1
         export TEST_CORECLR_FSHARP_SUITE=1
         export TEST_CORECLR_COREUNIT_SUITE=1
     fi
 
-    if [ $BUILD_PORTABLE -eq 1 ]; then
-        export TEST_PORTABLE_COREUNIT_SUITE=1
-    fi
-
-    if [ $BUILD_VS -eq 1 ]; then
-        export TEST_VS_IDEUNIT_SUITE=1
-    fi
 fi
 
 # If the `PB_SKIPTESTS` variable is set to 'true' then no tests should be built or run, even if explicitly specified
-if [ $PB_SKIPTESTS -eq "true" ]; then
+if [ "$PB_SKIPTESTS" = "true" ]; then
     export TEST_NET40_COMPILERUNIT_SUITE=0
     export TEST_NET40_COREUNIT_SUITE=0
     export TEST_NET40_FSHARP_SUITE=0
-    export TEST_NET40_FSHARPQA_SUITE=0
     export TEST_CORECLR_COREUNIT_SUITE=0
     export TEST_CORECLR_FSHARP_SUITE=0
-    export TEST_PORTABLE_COREUNIT_SUITE=0
-    export TEST_VS_IDEUNIT_SUITE=0
 fi
 
 #
@@ -386,8 +257,6 @@ printf "BUILD_PROTO_WITH_CORECLR_LKG=%s\n" "$BUILD_PROTO_WITH_CORECLR_LKG"
 printf "BUILD_NET40=%s\n" "$BUILD_NET40"
 printf "BUILD_NET40_FSHARP_CORE=%s\n" "$BUILD_NET40_FSHARP_CORE"
 printf "BUILD_CORECLR=%s\n" "$BUILD_CORECLR"
-printf "BUILD_PORTABLE=%s\n" "$BUILD_PORTABLE"
-printf "BUILD_VS=%s\n" "$BUILD_VS"
 printf "BUILD_SETUP=%s\n" "$BUILD_SETUP"
 printf "BUILD_CONFIG=%s\n" "$BUILD_CONFIG"
 printf "BUILD_PUBLICSIGN=%s\n" "$BUILD_PUBLICSIGN"
@@ -398,21 +267,12 @@ printf "\n"
 printf "TEST_NET40_COMPILERUNIT_SUITE=%s\n" "$TEST_NET40_COMPILERUNIT_SUITE"
 printf "TEST_NET40_COREUNIT_SUITE=%s\n" "$TEST_NET40_COREUNIT_SUITE"
 printf "TEST_NET40_FSHARP_SUITE=%s\n" "$TEST_NET40_FSHARP_SUITE"
-printf "TEST_NET40_FSHARPQA_SUITE=%s\n" "$TEST_NET40_FSHARPQA_SUITE"
 printf "TEST_CORECLR_COREUNIT_SUITE=%s\n" "$TEST_CORECLR_COREUNIT_SUITE"
 printf "TEST_CORECLR_FSHARP_SUITE=%s\n" "$TEST_CORECLR_FSHARP_SUITE"
-printf "TEST_PORTABLE_COREUNIT_SUITE=%s\n" "$TEST_PORTABLE_COREUNIT_SUITE"
-printf "TEST_VS_IDEUNIT_SUITE=%s\n" "$TEST_VS_IDEUNIT_SUITE"
 printf "INCLUDE_TEST_SPEC_NUNIT=%s\n" "$INCLUDE_TEST_SPEC_NUNIT"
 printf "INCLUDE_TEST_TAGS=%s\n" "$INCLUDE_TEST_TAGS"
 printf "\n"
 
-# TODO: Print out environment variables?
-printf "Environment\n"
-printf "\n"
-printf "(TODO)\n"
-printf "\n"
-printf "\n"
 
 build_status "Done with arguments, starting preparation"
 
@@ -422,7 +282,7 @@ msbuildflags=""
 # Perform any necessary setup and system configuration prior to running builds.
 ./before_install.sh
 rc=$?;
-if [ $rc -ne 0 ]; then
+if [ "$rc" != "0" ]; then
     printf "before_install script failed.\n"
     exit $rc
 fi
@@ -458,23 +318,10 @@ if [ "${RestorePackages:-true}" = 'true' ]; then
         failwith "Nuget restore failed"
     fi
 
-    if [ "$BUILD_VS" = '1' ]; then
-        eval "$_nugetexe restore vsintegration/packages.config $_nugetoptions"
-        if [ $? -ne 0 ]; then
-            failwith "Nuget restore failed"
-        fi
-    fi
-
-    if [ "$BUILD_SETUP" = '1' ]; then
-        eval "$_nugetexe restore setup/packages.config $_nugetoptions"
-        if [ $? -ne 0 ]; then
-            failwith "Nuget restore failed"
-        fi
-    fi
 fi
 
 # If building for CoreCLR, restore the Tools directory.
-if [ "$BUILD_PROTO_WITH_CORECLR_LKG" = '1' ]; then
+if [ "$BUILD_PROTO_WITH_CORECLR_LKG" = "1" ]; then
     # Restore the Tools directory
     ./init-tools.sh
     rc=$?;
@@ -497,10 +344,10 @@ _dotnetexe=dotnet
 _architecture=win7-x64
 
 # Build Proto
-if [ "$BUILD_PROTO" = '1' ]; then
+if [ "$BUILD_PROTO" = "1" ]; then
     rm -rfd Proto
 
-    if [ "$BUILD_PROTO_WITH_CORECLR_LKG" = '1' ]; then
+    if [ "$BUILD_PROTO_WITH_CORECLR_LKG" = "1" ]; then
         { pushd ./lkg/fsc && eval "$_dotnetexe restore" && popd; } || failwith "dotnet restore failed"
         { pushd ./lkg/fsi && eval "$_dotnetexe restore" && popd; } || failwith "dotnet restore failed"
         
@@ -512,58 +359,26 @@ if [ "$BUILD_PROTO" = '1' ]; then
 #        { printeval "$_ngenexe install Proto/net40/bin/fsc-proto.exe /nologo"; } || failwith "NGen of proto failed"
     else
         # Build proto-compiler and libs
-        { printeval "$_msbuildexe $msbuildflags src/fsharp-proto-build.proj /p:UseMonoPackaging=true /p:Configuration=Proto /p:DisableLocalization=true"; } || failwith "compiler proto build failed"
+        { printeval "$_msbuildexe $msbuildflags src/fsharp-proto-build.proj /p:Configuration=Proto /p:DisableLocalization=true"; } || failwith "compiler proto build failed"
     fi
 fi
 
 
 build_status "Done with proto, starting build"
 
-if [ "$BUILD_PHASE" = '1' ]; then
-    cmd="$_msbuildexe $msbuildflags build-everything.proj /p:UseMonoPackaging=true /p:Configuration=$BUILD_CONFIG $BUILD_DIAG /p:BUILD_PUBLICSIGN=$BUILD_PUBLICSIGN"
+if [ "$BUILD_PHASE" = "1" ]; then
+    cmd="$_msbuildexe $msbuildflags build-everything.proj /p:Configuration=$BUILD_CONFIG $BUILD_DIAG /p:BUILD_PUBLICSIGN=$BUILD_PUBLICSIGN"
     { printeval "$cmd"; } || failwith "'$cmd' failed"
 fi
 
-build_status "Main part of build finished, completing parts of build needed for Mono setup"
-
-if [ "$BUILD_NET40" = '1' ]; then
-    { printeval "./autogen.sh --prefix=/usr"; } || failwith "./autogen.sh failed"
-
-    { printeval "make"; } || failwith "make failed"
-fi
-
-build_status "Done with build, starting update/prepare"
-
-if [ "$BUILD_NET40" = '1' ]; then
-
-    { printeval "sudo make install"; } || failwith "sudo make install failed"
-
-# WINDOWS:
-#    src/update.sh $BUILD_CONFIG
-#    rc=$?;
-#    if [ $rc -ne 0 ]; then
-#        printf "src/update script failed.\n"
-#        exit $rc
-#    fi
-fi
-
-NUNITPATH="packages/NUnit.Console.3.0.0/tools/"
-printf "set NUNITPATH=%s\n" "$NUNITPATH"
-if [ ! -d "$NUNITPATH" ]; then
-    failwith "Could not find $NUNITPATH"
-fi
-
-{ printeval "cp -R $NUNITPATH ${_scriptdir}tests/fsharpqa/testenv/bin/nunit"; } || failwith "unable to copy nunit binaries to fsharpqa"
-{ printeval "cp -R ${_scriptdir}tests/fsharpqa/testenv/src/nunit ${_scriptdir}tests/fsharpqa/testenv/bin/nunit"; } || failwith "unable to copy nunit binaries to fsharpqa"
-
-# TODO: Define location of ildasm/monodis and sn
-
-if [ "$TEST_NET40_COMPILERUNIT_SUITE" = '0' ] && [ "$TEST_PORTABLE_COREUNIT_SUITE" = '0' ] && [ "$TEST_CORECLR_COREUNIT_SUITE" = '0' ] && [ "$TEST_VS_IDEUNIT_SUITE" = '0' ] && [ "$TEST_NET40_FSHARP_SUITE" = '0' ] && [ "$TEST_NET40_FSHARPQA_SUITE" = '0' ]; then
+if [ "$TEST_NET40_COMPILERUNIT_SUITE" != "1" ] && [ "$TEST_CORECLR_COREUNIT_SUITE" != "1" ] && [ "$TEST_NET40_FSHARP_SUITE" != "1" ]; then
     # Successful build; not running tests so exit now.
     exit 0
 fi
 
-if [ $no_test -eq 1 ]; then
+NUNITPATH="packages/NUnit.Console.3.0.0/tools/"
+
+if [ "$no_test" = "1" ]; then
     # Successful build; not running tests so exit now.
     exit 0
 fi
@@ -580,15 +395,7 @@ fi
 
 printf "WHERE_ARG_NUNIT=%s\n" "$WHERE_ARG_NUNIT"
 
-export NUNITPATH="tests/fsharpqa/testenv/bin/nunit/"
 export NUNIT3_CONSOLE="${NUNITPATH}nunit3-console.exe"
-export link_exe="${_scriptdir}packages/VisualCppTools.14.0.24519-Pre/lib/native/bin/link.exe"
-if [ ! -f "$link_exe" ]; then
-    failwith "failed to find '$link_exe' use nuget to restore the VisualCppTools package"
-fi
-
-#if /I not '$single_threaded' == 'true' (set PARALLEL_ARG=-procs:$NUMBER_OF_PROCESSORS) else set PARALLEL_ARG=-procs:0
-
 export FSCBINPATH="${_scriptdir}$BUILD_CONFIG/net40/bin"
 export RESULTSDIR="${_scriptdir}tests/TestResults"
 if [ ! -d "$RESULTSDIR" ]; then
@@ -597,19 +404,18 @@ fi
 
 printf "FSCBINPATH=%s\n" "$FSCBINPATH"
 printf "RESULTSDIR=%s\n" "$RESULTSDIR"
-printf "link_exe=%s\n" "$link_exe"
 printf "NUNIT3_CONSOLE=%s\n" "$NUNIT3_CONSOLE"
 printf "NUNITPATH=%s\n" "$NUNITPATH"
 
 # ---------------- net40-fsharp  -----------------------
 
-if [ "$TEST_NET40_FSHARP_SUITE" = '1' ]; then
+if [ "$TEST_NET40_FSHARP_SUITE" = "1" ]; then
     OUTPUTARG=""
     ERRORARG=""
     OUTPUTFILE=""
     ERRORFILE=""
     XMLFILE="$RESULTSDIR/test-net40-fsharp-results.xml"
-    if [ "$CI" = '1' ]; then
+    if [ "$CI" = "1" ]; then
         OUTPUTFILE="$RESULTSDIR/test-net40-fsharp-output.log"
         OUTPUTARG="--output:\"$OUTPUTFILE\""
         ERRORFILE="$RESULTSDIR/test-net40-fsharp-errors.log"
@@ -630,14 +436,14 @@ fi
 
 # ---------------- net40-compilerunit  -----------------------
 
-if [ "$TEST_NET40_COMPILERUNIT_SUITE" = '1' ]; then
+if [ "$TEST_NET40_COMPILERUNIT_SUITE" = "1" ]; then
 
     OUTPUTARG=""
     ERRORARG=""
     OUTPUTFILE=""
     ERRORFILE="$RESULTSDIR/test-net40-compilerunit-errors.log"
     XMLFILE="$RESULTSDIR/test-net40-compilerunit-results.xml"
-    if [ "$CI" = '1' ]; then
+    if [ "$CI" = "1" ]; then
         OUTPUTFILE="$RESULTSDIR/test-net40-compilerunit-output.log"
 	    ERRORARG="--err:\"$ERRORFILE\""
 	    OUTPUTARG="--output:\"$OUTPUTFILE\""
@@ -661,14 +467,14 @@ fi
 
 # ---------------- net40-coreunit  -----------------------
 
-if [ "$TEST_NET40_COREUNIT_SUITE" = '1' ]; then
+if [ "$TEST_NET40_COREUNIT_SUITE" = "1" ]; then
 
     OUTPUTARG=""
     ERRORARG=""
     OUTPUTFILE=""
     ERRORFILE=""
     XMLFILE="$RESULTSDIR/test-net40-coreunit-results.xml"
-    if [ "$CI" = '1' ]; then
+    if [ "$CI" = "1" ]; then
         ERRORFILE="$RESULTSDIR/test-net40-coreunit-errors.log"
         OUTPUTFILE="$RESULTSDIR/test-net40-coreunit-output.log"
 	    ERRORARG="--err:\"$ERRORFILE\""
@@ -691,42 +497,10 @@ if [ "$TEST_NET40_COREUNIT_SUITE" = '1' ]; then
     fi
 fi
 
-#  ---------------- portable-coreunit  -----------------------
-
-if [ "$TEST_PORTABLE_COREUNIT_SUITE" = '1' ]; then
-
-    OUTPUTARG=""
-    ERRORARG=""
-    OUTPUTFILE=""
-    ERRORFILE=""
-    XMLFILE="$RESULTSDIR/test-portable-coreunit-results.xml"
-
-    if [ "$CI" = '1' ]; then
-    	OUTPUTFILE="$RESULTSDIR/test-portable-coreunit-output.log"
-	    ERRORFILE="$RESULTSDIR/test-portable-coreunit-errors.log"
-        ERRORARG="--err:\"$ERRORFILE\""
-        OUTPUTARG="--output:\"$OUTPUTFILE\""
-	fi
-
-    if ! printeval "mono $NUNIT3_CONSOLE /framework:V4.0 /result=\"$XMLFILE;format=nunit3\" $OUTPUTARG $ERRORARG /work=\"$FSCBINPATH\" \"$FSCBINPATH/../../portable7/bin/FSharp.Core.UnitTests.dll\" \"$FSCBINPATH/../../portable47/bin/FSharp.Core.UnitTests.dll\" \"$FSCBINPATH/../../portable78/bin/FSharp.Core.UnitTests.dll\" \"$FSCBINPATH/../../portable259/bin/FSharp.Core.UnitTests.dll\" $WHERE_ARG_NUNIT"; then
-        if [ -f "$OUTPUTFILE" ]; then
-            echo -----------------------------------------------------------------
-            cat "$OUTPUTFILE"
-        fi
-        if [ -f "$ERRORFILE" ]; then
-            echo -----------------------------------------------------------------
-            cat "$ERRORFILE"
-        fi
-        echo -----------------------------------------------------------------
-        echo Error: Running tests portable-coreunit failed, see logs above -- FAILED
-        echo -----------------------------------------------------------------
-        exit 1
-    fi
-fi
 
 #  ---------------- coreclr-coreunit  -----------------------
 
-if [ "$TEST_CORECLR_COREUNIT_SUITE" = '1' ]; then
+if [ "$TEST_CORECLR_COREUNIT_SUITE" = "1" ]; then
 
     XMLFILE="$RESULTSDIR/test-coreclr-coreunit-results.xml"
     OUTPUTFILE="$RESULTSDIR/test-coreclr-coreunit-output.log"
@@ -742,7 +516,7 @@ fi
 
 # ---------------- coreclr-fsharp  -----------------------
 
-if [ "$TEST_CORECLR_FSHARP_SUITE" = '1' ]; then
+if [ "$TEST_CORECLR_FSHARP_SUITE" = "1" ]; then
 
     export single_threaded=true
     export permutations=FSC_CORECLR
@@ -760,43 +534,3 @@ if [ "$TEST_CORECLR_FSHARP_SUITE" = '1' ]; then
     fi
 fi
 
-# ---------------- net40-fsharpqa  -----------------------
-
-OSARCH="${PROCESSOR_ARCHITECTURE:-x64}"
-
-# Set this to 1 in order to use an external compiler host process
-#    This only has an effect when running the FSHARPQA tests, but can
-#    greatly speed up execution since fsc.exe does not need to be spawned thousands of times
-HOSTED_COMPILER=1
-
-if [ "$TEST_NET40_FSHARPQA_SUITE" = '1' ]; then
-
-	export FSC="$FSCBINPATH/fsc.exe"
-	export FSCOREDLLPATH="$FSCBINPATH/FSharp.Core.dll"
-	export PATH="$FSCBINPATH;$PATH"
-
-    if ! command -v perl > /dev/null; then
-		failwith "perl is not in the PATH, it is required for the net40-fsharpqa test suite"
-	fi
-
-	OUTPUTFILE=test-net40-fsharpqa-results.log
-	ERRORFILE=test-net40-fsharpqa-errors.log
-	FAILENV=test-net40-fsharpqa-errors
-
-	{ pushd "${_scriptdir}tests/fsharpqa/source" && \
-      printeval "perl tests/fsharpqa/testenv/bin/runall.pl -resultsroot $RESULTSDIR -results $OUTPUTFILE -log $ERRORFILE -fail $FAILENV -cleanup:no $TTAGS_ARG_RUNALL $PARALLEL_ARG" && \
-      popd; } || {
-        if [ -f "$RESULTSDIR/$OUTPUTFILE" ]; then
-            echo -----------------------------------------------------------------
-            cat "$RESULTSDIR/$OUTPUTFILE"
-        fi
-        if [ -f "$RESULTSDIR/$ERRORFILE" ]; then
-            echo -----------------------------------------------------------------
-            cat "$RESULTSDIR/$ERRORFILE"
-        fi
-        echo -----------------------------------------------------------------
-        echo Error: Running tests net40-fsharpqa failed, see logs above -- FAILED
-        echo -----------------------------------------------------------------
-        exit 1
-      }
-fi
diff --git a/build/targets/GitHash.props b/build/targets/GitHash.props
index 817240dbcab..e03e736e512 100644
--- a/build/targets/GitHash.props
+++ b/build/targets/GitHash.props
@@ -5,7 +5,7 @@
 Copied from RepoToolset. Might be slightly modified to adjust for the current F# build system specifics if necessary.
 -->
 
-<Project>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <!--
 
   Defines the following properties:
diff --git a/mono/appveyor.ps1 b/mono/appveyor.ps1
index b26a52d32f9..30445b98db0 100644
--- a/mono/appveyor.ps1
+++ b/mono/appveyor.ps1
@@ -1,6 +1,6 @@
 
 # the version under development, update after a release
-$version = '4.1.28'
+$version = '4.1.31'
 
 function isVersionTag($tag){
     $v = New-Object Version
diff --git a/netci.groovy b/netci.groovy
index cc7956a9834..7bb90e6b745 100644
--- a/netci.groovy
+++ b/netci.groovy
@@ -14,12 +14,14 @@ def static getBuildJobName(def configuration, def os) {
     osList.each { os ->
         def configurations = [];
         if (os == 'Windows_NT') {
-            configurations = ['Debug', 'Release_ci_part1', 'Release_ci_part2', 'Release_ci_part3', 'Release_net40_no_vs', 'Release_fcs' ];
+            configurations = ['Debug_default', 'Release_ci_part1', 'Release_ci_part2', 'Release_ci_part3', 'Release_net40_no_vs', 'Release_fcs' ];
         }
         else
         {
             // Linux
-            configurations = ['Release', 'Release_fcs' ];
+            // TODO: It should be possible to enable these configurations immediately subsequent to the PR containing this line
+            //configurations = ['Debug_default', 'Release_net40_test', 'Release_fcs' ];
+            configurations = [ 'Release_default', 'Release_fcs' ];
         }
         
         configurations.each { configuration ->
@@ -50,27 +52,37 @@ def static getBuildJobName(def configuration, def os) {
                     build_args = "Build"
                 }
             }
-            else if (configuration == "Debug") {
+            else if (configuration == "Debug_default") {
                 buildFlavor = "debug"
                 build_args = ""
             }
+            else if (configuration == "Release_default") {
+                buildFlavor = "release"
+                build_args = ""
+            }
+            else if (configuration == "Release_net40_test") {
+                buildFlavor = "release"
+                build_args = "net40 test"
+            }
+            else if (configuration == "Release_ci_part1") {
+                buildFlavor = "release"
+                build_args = "ci_part1"
+            }
+            else if (configuration == "Release_ci_part2") {
+                buildFlavor = "release"
+                build_args = "ci_part2"
+            }
+            else if (configuration == "Release_ci_part3") {
+                buildFlavor = "release"
+                build_args = "ci_part3"
+            }
+            else if (configuration == "Release_net40_no_vs") {
+                buildFlavor = "release"
+                build_args = "net40"
+            }
             else {
                 buildFlavor = "release"
-                if (configuration == "Release_ci_part1") {
-                    build_args = "ci_part1"
-                }
-                else if (configuration == "Release_ci_part2") {
-                    build_args = "ci_part2"
-                }
-                else if (configuration == "Release_ci_part3") {
-                    build_args = "ci_part3"
-                }
-                else if (configuration == "Release_net40_no_vs") {
-                    build_args = "net40"
-                }
-                else {
-                    build_args = "none"
-                }
+                build_args = "none"
             }
 
             if (os == 'Windows_NT') {
diff --git a/packages.config b/packages.config
index 8ef434167ea..48b6de3726b 100644
--- a/packages.config
+++ b/packages.config
@@ -21,6 +21,10 @@
   <package id="Microsoft.DiaSymReader" version="1.1.0" />
   <package id="System.ValueTuple" version="4.3.1" />
   <package id="Microsoft.VisualFSharp.Msbuild.15.0" version="1.0.1" />
+  <package id="Microsoft.Build" version="14.3.0" />
+  <package id="Microsoft.Build.Framework" version="14.3.0" />
+  <package id="Microsoft.Build.Utilities.Core" version="14.3.0" />
+  <package id="Microsoft.Build.Tasks.Core" version="14.3.0" />
 
   <!-- Testing -->
   <package id="FsCheck" version="2.6.2" />
diff --git a/scripts/dotnet-install.sh b/scripts/dotnet-install.sh
old mode 100644
new mode 100755
diff --git a/src/FSharpSource.Profiles.targets b/src/FSharpSource.Profiles.targets
index 274cbf5108d..8bcc8aa5f24 100644
--- a/src/FSharpSource.Profiles.targets
+++ b/src/FSharpSource.Profiles.targets
@@ -3,6 +3,7 @@
 <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
   <PropertyGroup Condition="'$(TargetDotnetProfile)'=='net40'">
+    <DefineConstants Condition="'$(MonoPackaging)' == 'true'">$(DefineConstants);CROSS_PLATFORM_COMPILER</DefineConstants>
     <DefineConstants>$(DefineConstants);ENABLE_MONO_SUPPORT</DefineConstants>
     <DefineConstants>$(DefineConstants);BE_SECURITY_TRANSPARENT</DefineConstants>
     <DefineConstants>$(DefineConstants);FX_LCIDFROMCODEPAGE</DefineConstants>
diff --git a/src/FSharpSource.Settings.targets b/src/FSharpSource.Settings.targets
index 35086a642f7..ee3810db644 100644
--- a/src/FSharpSource.Settings.targets
+++ b/src/FSharpSource.Settings.targets
@@ -98,19 +98,27 @@
     <NUnitLibDir>$(FSharpSourcesRoot)\..\packages\NUnit.$(NUnitVersion)\lib\net45</NUnitLibDir>
     <NUnitToolsLibDir>$(FSharpSourcesRoot)\..\packages\NUnit.ConsoleRunner\$(NUnitVersion)\tools\</NUnitToolsLibDir>
 
+    <MonoPackaging Condition="'$(TargetDotnetProfile)' != 'coreclr' AND '$(OS)' == 'Unix'">true</MonoPackaging>
+
     <!-- Localization -->
+    <DisableLocalization Condition="'$(MonoPackaging)' == 'true'">true</DisableLocalization>
     <UpdateXlfOnBuild Condition="'$(CI)' != '1'">true</UpdateXlfOnBuild>
     <XliffTasksVersion>0.2.0-beta-000076</XliffTasksVersion>
+
   </PropertyGroup>
 
+  <!-- Default setting. Some get modified later in FSharpSource.targets -->
   <PropertyGroup>
+    <SkipSigning>false</SkipSigning>
+    <UseOpenSourceSign>true</UseOpenSourceSign>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>$(FSharpSourcesRoot)\fsharp\msft.pubkey</AssemblyOriginatorKeyFile>
     <StrongNames>true</StrongNames>
     <DelaySign>true</DelaySign>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(OS)' != 'Unix'">
+  <!-- On windows, VS packaging -->
+  <PropertyGroup Condition="'$(MonoPackaging)' != 'true' AND '$(OS)' != 'Unix'">
     <UseMicroBuild>true</UseMicroBuild> 
     <UseSourceLink Condition = " '$(UseSourceLink)' == '' AND '$(Configuration)'=='Release' ">false</UseSourceLink>
     <UseGatherBinaries>true</UseGatherBinaries>
@@ -130,6 +138,7 @@
   <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
     <!-- Settings for Debug mode        -->
     <DebugType>full</DebugType>
+    <DebugType Condition="'$(OS)' == 'Unix'">portable</DebugType> <!-- no longer use MDB on Mono --> 
 
     <Optimize Condition=" '$(Optimize)' == '' ">false</Optimize>
     <ErrorReport Condition=" '$(ErrorReport)' == '' ">prompt</ErrorReport>
@@ -142,6 +151,7 @@
   <PropertyGroup Condition=" '$(Configuration)' == 'Release' ">
     <!-- Flags used for Release mode.		-->
     <DebugType>pdbonly</DebugType>
+    <DebugType Condition="'$(OS)' == 'Unix'">portable</DebugType> <!-- no longer use MDB on Mono --> 
 
     <Optimize Condition=" '$(Optimize)' == '' ">true</Optimize>
     <EmbedAllSource>false</EmbedAllSource>
@@ -153,6 +163,7 @@
   <PropertyGroup Condition="'$(Configuration)'=='Proto'">
     <!-- Flags used when running the Proto compiler.		-->
     <DebugType Condition=" '$(DebugType)' == '' ">full</DebugType>
+    <DebugType Condition="'$(OS)' == 'Unix'">portable</DebugType> <!-- no longer use MDB on Mono --> 
     <Optimize>true</Optimize>
     <DefineConstants>DEBUG;NO_STRONG_NAMES;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
@@ -196,6 +207,11 @@
     <!-- FSharp.Compiler.Tools is currently only used to get a working FSI.EXE to execute some scripts during the build -->
     <!-- The LKG FSI.EXE requires MSBuild 15 to be installed, which is painful -->
     <FsiToolPath>$(FSharpSourcesRoot)\..\packages\FSharp.Compiler.Tools.4.1.27\tools</FsiToolPath>
+
+
+    <!-- The version of MSBuild assumed byt the F# compiler in the Mono packaging of F# -->
+    <MonoPackagingMSBuildVersionFull>14.0.0.0</MonoPackagingMSBuildVersionFull>	  
+
   </PropertyGroup>
 
   <Import Project="$(MSBuildThisFileDirectory)..\packages\XliffTasks.$(XliffTasksVersion)\build\XliffTasks.props" Condition="'$(DisableLocalization)' != 'true'" />
diff --git a/src/FSharpSource.targets b/src/FSharpSource.targets
index c3f6de55051..206259ae082 100644
--- a/src/FSharpSource.targets
+++ b/src/FSharpSource.targets
@@ -8,74 +8,43 @@
 
   <Import Project="..\build\targets\GitHash.props" />
 
-  <Choose>
-    <When Condition="'$(Configuration)' == 'Debug' or '$(Configuration)' == 'Release' ">
-      <PropertyGroup>
-        <SkipSigning>false</SkipSigning><!-- Skip using the ,net toolset to generate signing . -->
-        <UseOpenSourceSign>true</UseOpenSourceSign>
-      </PropertyGroup>
-      <Choose>
-        <When Condition="'$(ProjectLanguage)' == 'FSharp'">
-          <Choose>
-            <!-- Some unit test assemblies must not have strong names since they reference other assemblies that don't have strong names -->
-            <!-- These unit test assemblies can't use InternalsVisibleTo into assemblies with strong names. -->
-            <When Condition="'$(StrongNames)' == 'false'" >
-              <PropertyGroup>
-                <SkipSigning>true</SkipSigning>
-                <UseOpenSourceSign>false</UseOpenSourceSign>
-                <MicroBuildAssemblyFileLanguage>fs</MicroBuildAssemblyFileLanguage>
-              </PropertyGroup>
-            </When>
-            <!-- In the Microsoft build we just delay-sign everything with the MSFT key -->
-            <!-- We have to do unit test DLLs well because they can see the internals of other strong-named DLLs -->
-            <Otherwise>
-              <PropertyGroup>
-                <DelaySign>true</DelaySign>
-                <StrongNames>true</StrongNames>
-                <MicroBuildAssemblyFileLanguage>fs</MicroBuildAssemblyFileLanguage>
-              </PropertyGroup>
-            </Otherwise>
-          </Choose>
-        </When>
-        <Otherwise>
-          <!-- Not F# code -->
-          <PropertyGroup>
-            <SignAssembly>true</SignAssembly>
-            <AssemblyOriginatorKeyFile>$(FSharpSourcesRoot)\fsharp\msft.pubkey</AssemblyOriginatorKeyFile>
-            <StrongNames>true</StrongNames>
-            <DelaySign>true</DelaySign>
-            <MicroBuildAssemblyFileLanguage>fs</MicroBuildAssemblyFileLanguage>
-          </PropertyGroup>
-        </Otherwise>
-      </Choose>
-    </When>
-    <Otherwise>
-      <PropertyGroup Condition="'$(StrongNames)' != 'true'">
-        <!-- For the proto build we don't use strong names. -->
-        <DefineConstants>NO_STRONG_NAMES;$(DefineConstants)</DefineConstants>
-        <MicroBuildAssemblyFileLanguage>fs</MicroBuildAssemblyFileLanguage>
-      </PropertyGroup>
-    </Otherwise>
-  </Choose>
+  <PropertyGroup>
+    <MicroBuildAssemblyFileLanguage>fs</MicroBuildAssemblyFileLanguage>
+  </PropertyGroup>
 
-  <PropertyGroup Condition="'$(UseMicroBuild)' != 'true'">
-    <OtherFlags >$(OtherFlags) --version:"$(MicroBuildAssemblyVersion)"</OtherFlags>
+  <!-- Some unit test assemblies must not have strong names since they reference other assemblies that don't have strong names -->
+  <!-- These unit test assemblies can't use InternalsVisibleTo into assemblies with strong names. -->
+  <PropertyGroup Condition="'$(StrongNames)' == 'false'">
+    <SkipSigning>true</SkipSigning>
+    <UseOpenSourceSign>false</UseOpenSourceSign>
+    <SignAssembly>false</SignAssembly>
+    <DefineConstants>NO_STRONG_NAMES;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(UseSourceLink)' == 'true'">
-    <SourceLink>$(IntermediateOutputPath)source_link.json</SourceLink>
+  <!-- On mono, use test.snk to sign private compiler binaries -->
+  <PropertyGroup Condition="'$(StrongNames)' != 'false' AND '$(MonoPackaging)' == 'true' AND '$(AssemblyName)' != 'FSharp.Core' AND '$(AssemblyName)' != 'FSharp.Compiler.Interactive.Settings'" >
+    <AssemblyOriginatorKeyFile>$(FSharpSourcesRoot)\fsharp\test.snk</AssemblyOriginatorKeyFile>
+    <DelaySign>false</DelaySign>
+    <DefineConstants>STRONG_NAME_FSHARP_COMPILER_WITH_TEST_KEY;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
 
-  <PropertyGroup Condition="'$(StrongNames)' != 'true'">
-    <DefineConstants>NO_STRONG_NAMES;$(DefineConstants)</DefineConstants>
+  <!-- On proto, use the FSharp.Core assembly version for everything (it only matters we get it right for FSharp.Core), and pass the version flag explicitly if not using MicroBuild -->
+  <PropertyGroup Condition="'$(Configuration)' == 'Proto'">
+    <MicroBuildAssemblyVersion>$(FSCoreVersion)</MicroBuildAssemblyVersion>
+    <OtherFlags>$(OtherFlags) --version:"$(MicroBuildAssemblyVersion)"</OtherFlags>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(UseSourceLink)' == 'true'">
+    <SourceLink>$(IntermediateOutputPath)source_link.json</SourceLink>
   </PropertyGroup>
 
+  <!-- We assume MSBuild 15.0 or greater. Note the Mono packaging doesn't actually rely on any specific version of MSBuild any longer except to build the MSBuild task-->
   <PropertyGroup>
     <DefineConstants>MSBUILD_AT_LEAST_14;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
 
+  <!-- Disable uwa toolchain nuget package resolve logic. -->
   <PropertyGroup>
-    <!-- Disable uwa toolchain nuget package resolve logic. -->
     <NuGetTargets  Condition="'$(NuGetTargets)' == ''">false</NuGetTargets>
   </PropertyGroup>  
 
@@ -126,7 +95,8 @@
     <TargetFrameworkOutputDirectory Condition="'$(FSharpCoreBackVersion)' == '3.0'">fsharp30\$(TargetDotnetProfile)</TargetFrameworkOutputDirectory>
     <TargetFrameworkOutputDirectory Condition="'$(FSharpCoreBackVersion)' == '3.1'">fsharp31\$(TargetDotnetProfile)</TargetFrameworkOutputDirectory>
     <TargetFrameworkOutputDirectory Condition="'$(FSharpCoreBackVersion)' == '4.0'">fsharp40\$(TargetDotnetProfile)</TargetFrameworkOutputDirectory>
-    <IntermediateOutputPath>obj\$(TargetFrameworkOutputDirectory)\</IntermediateOutputPath>
+    <TargetFrameworkOutputDirectory>$(TargetDotnetProfile)</TargetFrameworkOutputDirectory>
+    <IntermediateOutputPath>obj\$(Configuration)\$(TargetFrameworkOutputDirectory)\</IntermediateOutputPath>
   </PropertyGroup>
 
   <Choose>
@@ -380,9 +350,14 @@
 
   <Target Name="PrepareFSharpGenerateInternalsVisibleToFile"
           Condition="'$(Configuration)' != 'Proto' and '@(InternalsVisibleTo)' != ''">
-    <PropertyGroup>
+    <PropertyGroup Condition="'$(MonoPackaging)' != 'true'">
+      <!-- msft.pubkey delay signing of compiler binaries -->
       <_PublicKey>002400000480000094000000060200000024000052534131000400000100010007D1FA57C4AED9F0A32E84AA0FAEFD0DE9E8FD6AEC8F87FB03766C834C99921EB23BE79AD9D5DCC1DD9AD236132102900B723CF980957FC4E177108FC607774F29E8320E92EA05ECE4E821C0A5EFE8F1645C4C0C93C1AB99285D622CAA652C1DFAD63D745D6F2DE5F17E5EAF0FC4963D261C8A12436518206DC093344D5AD293</_PublicKey>
     </PropertyGroup>
+    <PropertyGroup Condition="'$(MonoPackaging)' == 'true'">
+      <!-- test.snk delay signing of compiler binaries -->
+      <_PublicKey>002400000480000094000000060200000024000052534131000400000100010077d32e043d184cf8cebf177201ec6fad091581a3a639a0534f1c4ebb3ab847a6b6636990224a04cf4bd1aec51ecec44cf0c8922eb5bb2ee65ec3fb9baa87e141042c96ce414f98af33508c7e24dab5b068aa802f6693881537ee0efcb5d3f1c9aaf8215ac42e92ba9a5a02574d6890d07464cb2f338b043b1c4ffe98efe069ee</_PublicKey>
+    </PropertyGroup>
     <ItemGroup>
       <_InternalsVisibleToAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
         <_Parameter1 Condition="'%(InternalsVisibleTo.Key)' != ''">%(InternalsVisibleTo.Identity), PublicKey=%(InternalsVisibleTo.Key)</_Parameter1>
diff --git a/src/buildfromsource/FSharp.Build/FSharp.Build.fsproj b/src/buildfromsource/FSharp.Build/FSharp.Build.fsproj
index 4fe08c815b5..f49ecb73381 100644
--- a/src/buildfromsource/FSharp.Build/FSharp.Build.fsproj
+++ b/src/buildfromsource/FSharp.Build/FSharp.Build.fsproj
@@ -17,7 +17,6 @@
       <Link>FSBuild.resx</Link>
     </EmbeddedResource>
     <Compile Include="FSBuild.fs" />
-    <Compile Include="$(FSharpSourcesRoot)\fsharp\FSharp.Build\InternalsVisibleTo.fs" />
     <Compile Include="AssemblyInfo.fs" />
     <Compile Include="..\..\utils\CompilerLocationUtils.fs" />
     <Compile Include="..\..\utils\reshapedreflection.fs" />
diff --git a/src/buildfromsource/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj b/src/buildfromsource/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
index 7cea584c57f..406efaf8a03 100644
--- a/src/buildfromsource/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
+++ b/src/buildfromsource/FSharp.Compiler.Interactive.Settings/FSharp.Compiler.Interactive.Settings.fsproj
@@ -18,7 +18,6 @@
       <Link>FSInteractiveSettings.resx</Link>
     </EmbeddedResource>
     <Compile Include="FSInteractiveSettings.fs" />
-    <Compile Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Interactive.Settings\InternalsVisibleTo.fs" />
     <Compile Include="AssemblyInfo.fs" />
     <Compile Include="InternalsVisibleTo.fs" />
     <Compile Include="..\..\utils\reshapedreflection.fs" />
diff --git a/src/buildfromsource/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj b/src/buildfromsource/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
index ef26074ad54..655cfa81140 100644
--- a/src/buildfromsource/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
+++ b/src/buildfromsource/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
@@ -608,9 +608,6 @@
       <Link>InteractiveSession\fsi.fs</Link>
     </Compile>
 
-    <Compile Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Private\InternalsVisibleTo.fs" Condition="'$(TargetDotnetProfile)' != 'coreclr'">
-      <Link>Misc/InternalsVisibleTo.fs</Link>
-    </Compile>
     <Compile Include="$(FSharpSourcesRoot)\fsharp\MSBuildReferenceResolver.fs">
       <Link>Misc/MSBuildReferenceResolver.fs</Link>
     </Compile>
diff --git a/src/buildfromsource/Fsc/Fsc.fsproj b/src/buildfromsource/Fsc/Fsc.fsproj
index 5ee390de338..58b44242fd4 100644
--- a/src/buildfromsource/Fsc/Fsc.fsproj
+++ b/src/buildfromsource/Fsc/Fsc.fsproj
@@ -15,7 +15,6 @@
 
   <Import Project="..\BuildFromSource.targets" />
   <ItemGroup>
-    <Compile Include="$(FSharpSourcesRoot)\fsharp\Fsc\InternalsVisibleTo.fs" />
     <Compile Include="AssemblyInfo.fs">
       <Link>Resources/AssemblyInfo.fs</Link>
     </Compile>
diff --git a/src/fsharp/FSharp.Build-proto/FSharp.Build-proto.fsproj b/src/fsharp/FSharp.Build-proto/FSharp.Build-proto.fsproj
index 8aba433807d..8ab9e33c93f 100644
--- a/src/fsharp/FSharp.Build-proto/FSharp.Build-proto.fsproj
+++ b/src/fsharp/FSharp.Build-proto/FSharp.Build-proto.fsproj
@@ -72,7 +72,7 @@
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
-  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr'">
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' != 'true' ">
     <Reference Include="Microsoft.Build.Framework, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Framework.dll</HintPath>
     </Reference>
@@ -90,5 +90,19 @@
       <Name>FSharp.Core</Name>
     </ProjectReference>
   </ItemGroup>
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' == 'true' ">
+    <Reference Include="Microsoft.Build.Framework, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Framework.14.3.0\lib\net45\Microsoft.Build.Framework.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.14.3.0\lib\net45\Microsoft.Build.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build.Utilities.Core, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Utilities.Core.14.3.0\lib\net45\Microsoft.Build.Utilities.Core.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build.Tasks.Core, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Tasks.Core.14.3.0\lib\net45\Microsoft.Build.Tasks.Core.dll</HintPath>
+    </Reference>
+  </ItemGroup>
   <Import Project="$(FSharpSourcesRoot)\FSharpSource.targets" />
 </Project>
diff --git a/src/fsharp/FSharp.Build/FSharp.Build.fsproj b/src/fsharp/FSharp.Build/FSharp.Build.fsproj
index e432279f749..a24d03a6ac3 100644
--- a/src/fsharp/FSharp.Build/FSharp.Build.fsproj
+++ b/src/fsharp/FSharp.Build/FSharp.Build.fsproj
@@ -53,13 +53,13 @@
     </CopyAndSubstituteText>
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' ">
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr'">
     <Reference Include="mscorlib" />
     <Reference Include="System" />
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq" />
   </ItemGroup>
-  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr'">
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' != 'true' ">
     <Reference Include="Microsoft.Build.Framework, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Framework.dll</HintPath>
     </Reference>
@@ -73,6 +73,20 @@
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Tasks.Core.dll</HintPath>
     </Reference>
   </ItemGroup>
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' == 'true' ">
+    <Reference Include="Microsoft.Build.Framework, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Framework.14.3.0\lib\net45\Microsoft.Build.Framework.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.14.3.0\lib\net45\Microsoft.Build.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build.Utilities.Core, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Utilities.Core.14.3.0\lib\net45\Microsoft.Build.Utilities.Core.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build.Tasks.Core, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Tasks.Core.14.3.0\lib\net45\Microsoft.Build.Tasks.Core.dll</HintPath>
+    </Reference>
+  </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Core\FSharp.Core.fsproj">
       <Project>{DED3BBD7-53F4-428A-8C9F-27968E768605}</Project>
diff --git a/src/fsharp/FSharp.Compiler.Interactive.Settings/InternalsVisibleTo.fs b/src/fsharp/FSharp.Compiler.Interactive.Settings/InternalsVisibleTo.fs
deleted file mode 100644
index 3071a74b616..00000000000
--- a/src/fsharp/FSharp.Compiler.Interactive.Settings/InternalsVisibleTo.fs
+++ /dev/null
@@ -1,10 +0,0 @@
-// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
-
-namespace Microsoft.FSharp
-open System.Reflection
-[<assembly:System.Runtime.CompilerServices.InternalsVisibleTo("fsi, PublicKey=002400000480000094000000060200000024000052534131000400000100010007D1FA57C4AED9F0A32E84AA0FAEFD0DE9E8FD6AEC8F87FB03766C834C99921EB23BE79AD9D5DCC1DD9AD236132102900B723CF980957FC4E177108FC607774F29E8320E92EA05ECE4E821C0A5EFE8F1645C4C0C93C1AB99285D622CAA652C1DFAD63D745D6F2DE5F17E5EAF0FC4963D261C8A12436518206DC093344D5AD293")>]
-[<assembly:System.Runtime.CompilerServices.InternalsVisibleTo("fsiAnyCpu, PublicKey=002400000480000094000000060200000024000052534131000400000100010007D1FA57C4AED9F0A32E84AA0FAEFD0DE9E8FD6AEC8F87FB03766C834C99921EB23BE79AD9D5DCC1DD9AD236132102900B723CF980957FC4E177108FC607774F29E8320E92EA05ECE4E821C0A5EFE8F1645C4C0C93C1AB99285D622CAA652C1DFAD63D745D6F2DE5F17E5EAF0FC4963D261C8A12436518206DC093344D5AD293")>]
-[<assembly:System.Runtime.CompilerServices.InternalsVisibleTo("FSharp.Compiler, PublicKey=002400000480000094000000060200000024000052534131000400000100010007D1FA57C4AED9F0A32E84AA0FAEFD0DE9E8FD6AEC8F87FB03766C834C99921EB23BE79AD9D5DCC1DD9AD236132102900B723CF980957FC4E177108FC607774F29E8320E92EA05ECE4E821C0A5EFE8F1645C4C0C93C1AB99285D622CAA652C1DFAD63D745D6F2DE5F17E5EAF0FC4963D261C8A12436518206DC093344D5AD293")>]
-
-do()
-
diff --git a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
index e871d61d4c7..0d135f2ee15 100644
--- a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
+++ b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
@@ -642,17 +642,17 @@
       <Link>FSIstrings.txt</Link>
     </EmbeddedText>
     <Compile Include="..\fsi\fsi.fsi">
-      <Link>InteractiveSession\fsi.fsi</Link>
+      <Link>InteractiveSession/fsi.fsi</Link>
     </Compile>
     <Compile Include="..\fsi\fsi.fs">
-      <Link>InteractiveSession\fsi.fs</Link>
+      <Link>InteractiveSession/fsi.fs</Link>
     </Compile>
 
-    <Compile Include="..\MSBuildReferenceResolver.fs">
+    <Compile Include="..\MSBuildReferenceResolver.fs"  Condition="'$(MonoPackaging)' != 'true'">
       <Link>Misc/MSBuildReferenceResolver.fs</Link>
     </Compile>
     <!-- an old API for testing the compiler and gathering diagnostics in-memory -->
-    <Compile Include="..\LegacyHostedCompilerForTesting.fs">
+    <Compile Include="..\LegacyHostedCompilerForTesting.fs" Condition="'$(MonoPackaging)' != 'true'">
       <Link>Misc/LegacyHostedCompilerForTesting.fs</Link>
     </Compile>
   </ItemGroup>
@@ -684,6 +684,8 @@
       <HintPath>..\..\..\packages\System.ValueTuple.4.3.1\lib\netstandard1.0\System.ValueTuple.dll</HintPath>
       <Private>true</Private>
     </Reference>
+  </ItemGroup>
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' != 'true' ">
     <Reference Include="Microsoft.Build.Framework, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Framework.dll</HintPath>
     </Reference>
diff --git a/src/fsharp/FSharp.Core/FSharp.Core.fsproj b/src/fsharp/FSharp.Core/FSharp.Core.fsproj
index f24ede9f1b2..32c5f015302 100644
--- a/src/fsharp/FSharp.Core/FSharp.Core.fsproj
+++ b/src/fsharp/FSharp.Core/FSharp.Core.fsproj
@@ -34,7 +34,7 @@
     <None Include="FSharp.Core.runtimeconfig.json"      Condition="'$(TargetDotnetProfile)' == 'coreclr'" ><CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory></None>
   </ItemGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(Configuration)' != 'Proto'">
     <CustomAdditionalCompileInputs Include="$(FSharpSourcesRoot)\..\Proto\$(ProtoFlavour)\bin\fsc-proto.exe">
       <Visible>false</Visible>
     </CustomAdditionalCompileInputs>
diff --git a/src/fsharp/Fsc-proto/Fsc-proto.fsproj b/src/fsharp/Fsc-proto/Fsc-proto.fsproj
index fd3d209e512..8c49f5fcf6a 100644
--- a/src/fsharp/Fsc-proto/Fsc-proto.fsproj
+++ b/src/fsharp/Fsc-proto/Fsc-proto.fsproj
@@ -438,7 +438,10 @@
     <Compile Include="..\fsc.fs">
       <Link>fsc.fs</Link>
     </Compile>
-    <Compile Include="..\MSBuildReferenceResolver.fs">
+    <Compile Include="..\SimulatedMSBuildReferenceResolver.fs" Condition="'$(MonoPackaging)' == 'true'">
+      <Link>Service/SimulatedMSBuildReferenceResolver.fs</Link>
+    </Compile>
+    <Compile Include="..\MSBuildReferenceResolver.fs"  Condition="'$(MonoPackaging)' != 'true'">
       <Link>MSBuildReferenceResolver.fs</Link>
     </Compile>
     <Compile Include="..\fscmain.fs">
@@ -473,7 +476,7 @@
       <Name>FSharp.Core</Name>
     </ProjectReference>
   </ItemGroup>
-  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr'">
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' != 'true' AND '$(OS)' != 'Unix' ">
     <Reference Include="Microsoft.Build.Framework, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Framework.dll</HintPath>
     </Reference>
diff --git a/src/fsharp/fscmain.fs b/src/fsharp/fscmain.fs
index 9405af123bb..344656d6b52 100644
--- a/src/fsharp/fscmain.fs
+++ b/src/fsharp/fscmain.fs
@@ -48,7 +48,14 @@ module Driver =
                     failwithf "%s" <| FSComp.SR.elSysEnvExitDidntExit() 
             }
 
-        mainCompile (ctok, argv, MSBuildReferenceResolver.Resolver, (*bannerAlreadyPrinted*)false, (*openBinariesInMemory*)false, (*defaultCopyFSharpCore*)true, quitProcessExiter, ConsoleLoggerProvider(), None, None)
+        let legacyReferenceResolver = 
+#if CROSS_PLATFORM_COMPILER
+            SimulatedMSBuildReferenceResolver.SimulatedMSBuildResolver
+#else
+            MSBuildReferenceResolver.Resolver
+#endif
+
+        mainCompile (ctok, argv, legacyReferenceResolver, (*bannerAlreadyPrinted*)false, (*openBinariesInMemory*)false, (*defaultCopyFSharpCore*)true, quitProcessExiter, ConsoleLoggerProvider(), None, None)
         0 
 
 [<EntryPoint>]
diff --git a/src/fsharp/fsi/fsimain.fs b/src/fsharp/fsi/fsimain.fs
index b87c795a605..002cfa54a4f 100644
--- a/src/fsharp/fsi/fsimain.fs
+++ b/src/fsharp/fsi/fsimain.fs
@@ -235,6 +235,12 @@ let evaluateSession(argv: string[]) =
                 None
 #endif
 
+        let legacyReferenceResolver = 
+#if CROSS_PLATFORM_COMPILER
+            SimulatedMSBuildReferenceResolver.SimulatedMSBuildResolver
+#else
+            MSBuildReferenceResolver.Resolver
+#endif
         // Update the configuration to include 'StartServer', WinFormsEventLoop and 'GetOptionalConsoleReadLine()'
         let rec fsiConfig = 
             { new FsiEvaluationSessionHostConfig () with 
@@ -251,21 +257,21 @@ let evaluateSession(argv: string[]) =
                 member __.ReportUserCommandLineArgs args = fsiConfig0.ReportUserCommandLineArgs args
                 member __.EventLoopRun() = 
 #if !FX_NO_WINFORMS
-                    match fsiWinFormsLoop.Value with 
+                    match (if fsiSession.IsGui then fsiWinFormsLoop.Value else None) with 
                     | Some l -> (l :> IEventLoop).Run()
                     | _ -> 
 #endif
                     fsiConfig0.EventLoopRun()
                 member __.EventLoopInvoke(f) = 
 #if !FX_NO_WINFORMS
-                    match fsiWinFormsLoop.Value with 
+                    match (if fsiSession.IsGui then fsiWinFormsLoop.Value else None) with 
                     | Some l -> (l :> IEventLoop).Invoke(f)
                     | _ -> 
 #endif
                     fsiConfig0.EventLoopInvoke(f)
                 member __.EventLoopScheduleRestart() = 
 #if !FX_NO_WINFORMS
-                    match fsiWinFormsLoop.Value with 
+                    match (if fsiSession.IsGui then fsiWinFormsLoop.Value else None) with 
                     | Some l -> (l :> IEventLoop).ScheduleRestart()
                     | _ -> 
 #endif
@@ -279,7 +285,7 @@ let evaluateSession(argv: string[]) =
                 member __.GetOptionalConsoleReadLine(probe) = getConsoleReadLine(probe) }
 
         // Create the console
-        and fsiSession = FsiEvaluationSession.Create (fsiConfig, argv, Console.In, Console.Out, Console.Error, collectible=false, legacyReferenceResolver=MSBuildReferenceResolver.Resolver)
+        and fsiSession : FsiEvaluationSession = FsiEvaluationSession.Create (fsiConfig, argv, Console.In, Console.Out, Console.Error, collectible=false, legacyReferenceResolver=legacyReferenceResolver)
 
 
 #if !FX_NO_WINFORMS
diff --git a/src/fsharp/test.snk b/src/fsharp/test.snk
new file mode 100644
index 00000000000..c16543bdc48
Binary files /dev/null and b/src/fsharp/test.snk differ
diff --git a/src/utils/HashMultiMap.fs b/src/utils/HashMultiMap.fs
index 134597efc6a..89f3a4fc2a4 100644
--- a/src/utils/HashMultiMap.fs
+++ b/src/utils/HashMultiMap.fs
@@ -10,10 +10,13 @@ open Microsoft.FSharp.Collections
 // one entry. So use two hash tables: one for the main entries and one for the overflow.
 [<Sealed>]
 type internal HashMultiMap<'Key,'Value>(n: int, hasheq: IEqualityComparer<'Key>) = 
+
     let firstEntries = Dictionary<_,_>(n,hasheq)
+
     let rest = Dictionary<_,_>(3,hasheq)
  
     new (hasheq : IEqualityComparer<'Key>) = HashMultiMap<'Key,'Value>(11, hasheq)
+
     new (seq : seq<'Key * 'Value>, hasheq : IEqualityComparer<'Key>) as x = 
         new HashMultiMap<'Key,'Value>(11, hasheq)
         then seq |> Seq.iter (fun (k,v) -> x.Add(k,v))
@@ -35,7 +38,9 @@ type internal HashMultiMap<'Key,'Value>(n: int, hasheq: IEqualityComparer<'Key>)
          rest.Clear()
 
     member x.FirstEntries = firstEntries
+
     member x.Rest = rest
+
     member x.Copy() = 
         let res = HashMultiMap<'Key,'Value>(firstEntries.Count,firstEntries.Comparer)
         for kvp in firstEntries do 
@@ -114,6 +119,7 @@ type internal HashMultiMap<'Key,'Value>(n: int, hasheq: IEqualityComparer<'Key>)
     member x.Count = firstEntries.Count
 
     interface IEnumerable<KeyValuePair<'Key, 'Value>> with
+
         member s.GetEnumerator() = 
             let elems = List<_>(firstEntries.Count + rest.Count)
             for kvp in firstEntries do
@@ -123,34 +129,48 @@ type internal HashMultiMap<'Key,'Value>(n: int, hasheq: IEqualityComparer<'Key>)
             (elems.GetEnumerator() :> IEnumerator<_>)
 
     interface System.Collections.IEnumerable with
+
         member s.GetEnumerator() = ((s :> seq<_>).GetEnumerator() :> System.Collections.IEnumerator)
 
     interface IDictionary<'Key, 'Value> with 
+
         member s.Item 
             with get x = s.[x]            
             and  set x v = s.[x] <- v
             
         member s.Keys = ([| for kvp in s -> kvp.Key |] :> ICollection<'Key>)
+
         member s.Values = ([| for kvp in s -> kvp.Value |] :> ICollection<'Value>)
+
         member s.Add(k,v) = s.[k] <- v
+
         member s.ContainsKey(k) = s.ContainsKey(k)
+
         member s.TryGetValue(k,r) = if s.ContainsKey(k) then (r <- s.[k]; true) else false
+
         member s.Remove(k:'Key) = 
             let res = s.ContainsKey(k) in 
             s.Remove(k); res
 
     interface ICollection<KeyValuePair<'Key, 'Value>> with 
+
         member s.Add(x) = s.[x.Key] <- x.Value
+
         member s.Clear() = s.Clear()            
+
         member s.Remove(x) = 
             let res = s.ContainsKey(x.Key) 
             if res && Unchecked.equals s.[x.Key] x.Value then 
                 s.Remove(x.Key); 
             res
+
         member s.Contains(x) = 
             s.ContainsKey(x.Key) && 
             Unchecked.equals s.[x.Key] x.Value
+
         member s.CopyTo(arr,arrIndex) = s |> Seq.iteri (fun j x -> arr.[arrIndex+j] <- x)
+
         member s.IsReadOnly = false
+
         member s.Count = s.Count
 
diff --git a/src/utils/ResizeArray.fs b/src/utils/ResizeArray.fs
index b8720222dea..66613044349 100644
--- a/src/utils/ResizeArray.fs
+++ b/src/utils/ResizeArray.fs
@@ -10,9 +10,13 @@ open Microsoft.FSharp.Core.OptimizedClosures
 module internal ResizeArray =
 
     let length (arr: ResizeArray<'T>) =  arr.Count
+
     let get (arr: ResizeArray<'T>) (n: int) =  arr.[n]
+
     let set (arr: ResizeArray<'T>) (n: int) (x:'T) =  arr.[n] <- x
+
     let create  (n: int) x = new ResizeArray<_> (seq { for _ in 1 .. n -> x })
+
     let init (n: int) (f: int -> 'T) =  new ResizeArray<_> (seq { for i in 0 .. n-1 -> f i })
 
     let blit (arr1: ResizeArray<'T>) start1 (arr2: ResizeArray<'T>) start2 len =
@@ -25,6 +29,7 @@ module internal ResizeArray =
             arr2.[start2+i] <- arr1.[start1 + i]
 
     let concat (arrs: ResizeArray<'T> list) = new ResizeArray<_> (seq { for arr in arrs do for x in arr do yield x })
+
     let append (arr1: ResizeArray<'T>) (arr2: ResizeArray<'T>) = concat [arr1; arr2]
 
     let sub (arr: ResizeArray<'T>) start len =
@@ -176,10 +181,13 @@ module internal ResizeArray =
         res
 
     let toArray (arr: ResizeArray<'T>) = arr.ToArray()
+
     let ofArray (arr: 'T[]) = new ResizeArray<_>(arr)
+
     let toSeq (arr: ResizeArray<'T>) = Seq.readonly arr
 
     let sort f (arr: ResizeArray<'T>) = arr.Sort (System.Comparison(f))
+
     let sortBy f (arr: ResizeArray<'T>) = arr.Sort (System.Comparison(fun x y -> compare (f x) (f y)))
 
 
diff --git a/src/utils/TaggedCollections.fsi b/src/utils/TaggedCollections.fsi
index ba99df33762..c877cbe7eb5 100644
--- a/src/utils/TaggedCollections.fsi
+++ b/src/utils/TaggedCollections.fsi
@@ -107,10 +107,13 @@ namespace Internal.Utilities.Collections.Tagged
         member ToArray: unit -> 'T array 
 
         interface ICollection<'T> 
+
         interface IEnumerable<'T> 
+
         interface System.Collections.IEnumerable
 
         interface System.IComparable
+
         override Equals : obj -> bool
 
     type internal Set<'T> = Set<'T, IComparer<'T>>    
@@ -128,14 +131,13 @@ namespace Internal.Utilities.Collections.Tagged
     /// Immutable maps.  A constraint tag carries information about the class of key-comparers being used.  
     [<Sealed>]
     type internal Map<'Key,'Value,'ComparerTag>  when 'ComparerTag :> IComparer<'Key> =
+
         /// Return a new map with the binding added to the given map.
         member Add: 'Key * 'Value -> Map<'Key,'Value,'ComparerTag>
 
         /// Return True if there are no bindings in the map.
         member IsEmpty: bool
         
-        //member Comparer : 'ComparerTag
-
         /// The empty map, and use the given comparer comparison function for all operations associated
         /// with any maps built from this map.
         static member Empty: 'ComparerTag -> Map<'Key,'Value,'ComparerTag>
@@ -213,7 +215,9 @@ namespace Internal.Utilities.Collections.Tagged
         interface IEnumerable<KeyValuePair<'Key, 'Value>>
         
         interface System.Collections.IEnumerable 
+
         interface System.IComparable
+
         override Equals : obj -> bool
 
     type internal Map<'Key,'Value> = Map<'Key, 'Value, IComparer<'Key>>    
diff --git a/tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj b/tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj
index f0cc28128c1..0522cf51f50 100644
--- a/tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj
+++ b/tests/FSharp.Build.UnitTests/FSharp.Build.UnitTests.fsproj
@@ -41,6 +41,8 @@
       <Private>True</Private>
       <HintPath>$(NUnitLibDir)\nunit.framework.dll</HintPath>
     </Reference>
+  </ItemGroup>
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' != 'true' ">
     <Reference Include="Microsoft.Build.Framework, Version=$(VisualStudioVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Framework.dll</HintPath>
     </Reference>
@@ -54,6 +56,20 @@
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualFSharp.Msbuild.15.0.1.0.1\lib\net45\Microsoft.Build.Tasks.Core.dll</HintPath>
     </Reference>
   </ItemGroup>
+  <ItemGroup Condition=" '$(TargetDotnetProfile)' != 'coreclr' AND '$(MonoPackaging)' == 'true' ">
+    <Reference Include="Microsoft.Build.Framework, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Framework.14.3.0\lib\net45\Microsoft.Build.Framework.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.14.3.0\lib\net45\Microsoft.Build.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build.Utilities.Core, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Utilities.Core.14.3.0\lib\net45\Microsoft.Build.Utilities.Core.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.Build.Tasks.Core, Version=$(MonoPackagingMSBuildVersionFull), Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.Build.Tasks.Core.14.3.0\lib\net45\Microsoft.Build.Tasks.Core.dll</HintPath>
+    </Reference>
+  </ItemGroup>  
   <ItemGroup>
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Build\FSharp.Build.fsproj">
       <Project>{702A7979-BCF9-4C41-853E-3ADFC9897890}</Project>
diff --git a/tests/FSharp.Compiler.UnitTests/ProductVersion.fs b/tests/FSharp.Compiler.UnitTests/ProductVersion.fs
index db57334b730..94c87bf0e1a 100644
--- a/tests/FSharp.Compiler.UnitTests/ProductVersion.fs
+++ b/tests/FSharp.Compiler.UnitTests/ProductVersion.fs
@@ -1,6 +1,7 @@
 namespace FSharp.Compiler.UnitTests
 
 open System
+open System.IO
 open System.Text
 open NUnit.Framework
 
@@ -111,16 +112,19 @@ module TypeProviderDesignTimeComponentLoading =
 
     [<Test>]
     let ``check tooling paths for type provider design time component loading`` () =
-        let expected =
-          [ @"typeproviders\fsharp41\net461"
-            @"tools\fsharp41\net461"
-            @"typeproviders\fsharp41\net452"
-            @"tools\fsharp41\net452"
-            @"typeproviders\fsharp41\net451"
-            @"tools\fsharp41\net451"
-            @"typeproviders\fsharp41\net45"
-            @"tools\fsharp41\net45"
-            @"typeproviders\fsharp41\netstandard2.0"
-            @"tools\fsharp41\netstandard2.0" ]
+        let expected = 
+          [ Path.Combine("typeproviders", "fsharp41", "net461")
+            Path.Combine("tools", "fsharp41", "net461")
+            Path.Combine("typeproviders", "fsharp41", "net452")
+            Path.Combine("tools", "fsharp41", "net452")
+            Path.Combine("typeproviders", "fsharp41", "net451")
+            Path.Combine("tools", "fsharp41", "net451")
+            Path.Combine("typeproviders", "fsharp41", "net45")
+            Path.Combine("tools", "fsharp41", "net45")
+            Path.Combine("typeproviders", "fsharp41", "netstandard2.0")
+            Path.Combine("tools", "fsharp41", "netstandard2.0")
+          ]        
         let actual = Microsoft.FSharp.Compiler.ExtensionTyping.toolingCompatiblePaths()
-        Assert.areEqual expected actual
+        printfn "actual = %A" actual
+        printfn "expected = %A" expected
+        Assert.True((expected=actual))
diff --git a/tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj b/tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj
index f1e384f1d64..6dde86b7177 100644
--- a/tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj
+++ b/tests/FSharp.Core.UnitTests/FSharp.Core.Unittests.fsproj
@@ -118,8 +118,8 @@
     <Compile Include="StructTuples.fs" />
     <Compile Include="SurfaceArea.$(TargetDotnetProfile).fs" />
     <Compile Include="Program.fs" Condition="'$(TargetDotnetProfile)' == 'coreclr'" />
-    <CopyAndSubstituteText Include="FSharp.Core.UnitTests.dll.config">
-      <TargetFilename>FSharp.Core.UnitTests.dll.config</TargetFilename>
+    <CopyAndSubstituteText Include="FSharp.Core.Unittests.dll.config">
+      <TargetFilename>FSharp.Core.Unittests.dll.config</TargetFilename>
       <Pattern1>FSCoreVersion</Pattern1>
       <Replacement1>$(FSCoreVersion)</Replacement1>
     </CopyAndSubstituteText>
diff --git a/tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncModule.fs b/tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncModule.fs
index 0cc041bdfd9..252fa2913f0 100644
--- a/tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncModule.fs
+++ b/tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Control/AsyncModule.fs
@@ -612,24 +612,30 @@ type AsyncModule() =
             x := !x + 1 // Side effect!
             return "" }
 
-        let memFunc = Utils.memoizeAsync <| someSlowFunc
+        let memFunc : string -> Async<string> = Utils.memoizeAsync <| someSlowFunc
 
         async {
+            Console.WriteLine "Do the same memoized thing many ways...."
             do! memFunc "a" |> Async.Ignore
             do! memFunc "a" |> Async.Ignore
             do! memFunc "a" |> Async.Ignore
             do! [|1 .. 30|] |> Seq.map(fun _ -> (memFunc "a")) 
                 |> Async.Parallel |> Async.Ignore
+
+            Console.WriteLine "Still more ways...."
             for _i = 1 to 30 do
                 Async.Start( memFunc "a" |> Async.Ignore )
                 Async.Start( memFunc "a" |> Async.Ignore )
             do! Async.Sleep 500
             do! memFunc "a" |> Async.Ignore
             do! memFunc "a" |> Async.Ignore
+            Console.WriteLine "Still more ways again...."
             for _i = 1 to 30 do
                 Async.Start( memFunc "a" |> Async.Ignore )
 
+            Console.WriteLine "Still more ways again again...."
             do! [|1 .. 30|] |> Seq.map(fun _ -> (memFunc "a")) 
                 |> Async.Parallel |> Async.Ignore
         } |> Async.RunSynchronously
+        Console.WriteLine "Checking result...."
         Assert.AreEqual(1, !x)