midl : error MIDL9008: internal compiler problem

[Noemata]

When I upgraded this solution to the latest C++/winrt, I get an internal compiler problem. Initially all was fine moving over to VS2019. After using the Nuget package manager to upgrage Microsoft.Windows.CppWinRT to version 2.0.200203.5, the Dynamic lib build produces:

midl : error MIDL9008: internal compiler problem

Any ideas?

[johanlindfors]

@Noemata Please try to use the mentioned PR and see if it fixes the issue. I had to make some manual post-build events as well as upgrading to later version of Windows 10 SDK. Please let me know how it goes!

[Noemata]

Thank you very much for your help. Your adjustments mostly worked. I did find it more than a little distressful to have to make the changes below to your solution. I have no idea how mere mortals are supposed to figure this out. Without your input I would have been lost.

[ Changes for VS2019 v16.4.4 ]

IF "$(PlatformTarget)" NEQ "x86" copy /Y "$(ProjectDir)$(PlatformTarget)$(Configuration)\Merged$(AppxPriInitialPath).winmd" "$(TargetDir)$(AppxPriInitialPath).winmd"
IF "$(PlatformTarget)" EQU "x86" copy /Y "$(ProjectDir)$(Configuration)\Merged$(AppxPriInitialPath).winmd" "$(TargetDir)$(AppxPriInitialPath).winmd"

I'm using the latest VS2019 release. I was very surprised by the need to have the special handling for x86. I was even more surprised by the fact that this is clearly some form of regression, since this hoop jumping was previously not required.

It's been a challenge to keep C++/WinRT projects working. I love the premise of C++/WinRT, however the execution is becoming daunting with respect to backward compatibility.

I did try this on a couple different installations of VS2019. I'm quite curious why your setup seems to be different.

[Psychlist1972]

Just got this error today in my C++/WinRT project. It's possible it was caused by the BSOD I had earlier today (first in a very long time) from something unrelated. No upgrades of tools or anything. Not sure who owns the compiler, but the link from the error brings you to a page which doesn't actually include that error. Solutions I'm seeing around vary from the above to using a different Windows SDK version, to repaving your machine.

I'm guessing this is a catch-all error and there's no obvious way to get insight into what caused it?

[Psychlist1972]

Documenting for other:

Uninstalling and reinstalling all the Windows SDKs didn't fix it.
Resetting Visual Studio to see if that will do it. (Edit: it did not fix it)

Edit: I should have tried this first. In my case, it's a problem in the IDL itself. I need to sort out what, but it's not an issue with tools, SDKs, or anything. Just updating this in case others run across it.

In the end: the project file had two conflicting versions of the CPPWinRT package referenced for some strange reason, and some of the IDL had syntax errors. Some combo of that was lethal to the compiler. All working now.