Some syntax tree tests fail in Debug

[auduchinok]

#15343 introduced test failures when using Debug solution configuration:

System.AggregateException : One or more errors occurred. (One or more errors occurred. (Unknown exception seen in compiler: JetBrains.ReSharper.TestRunner.Logging.TraceListener+AssertionException: Unknown exception seen in compiler: JetBrains.ReSharper.TestRunner.Logging.TraceListener+AssertionException: Unexpected exception raised in compiler: value does not have a valid member type
FSharp.Compiler.DiagnosticsLogger+InternalError: value does not have a valid member type(5,8--5,9)

   at FSharp.Compiler.ParseAndCheckInputs.CheckOneInput@1276-2.Invoke(CancellationToken ct) in C:\Developer\fsharp-main-5\src\Compiler\Driver\ParseAndCheckInputs.fs:line 1346
   at FSharp.Compiler.ParseAndCheckInputs.CheckOneInput@1275-17.Invoke(CancellationToken ct)

   at FSharp.Compiler.CodeAnalysis.ParseAndCheckFile.CheckOneFile@2690-6.Invoke(CancellationToken ct) in C:\Developer\fsharp-main-5\src\Compiler\Service\FSharpCheckerResults.fs:line 2693
   at FSharp.Compiler.CodeAnalysis.ParseAndCheckFile.CheckOneFile@2680-8.Invoke(CancellationToken ct)
))

cc @T-Gro Could you please take a look?

I really wonder, why doesn't it fail in Release? Why doesn't it fail on CI?

[vzarytovskii]

I really wonder, why doesn't it fail in Release? Why doesn't it fail on CI?

It might be some sort of assert, which only fails in debug. Release is running in CI as well.

[T-Gro]

Will check it, thanks.

This errors is only thrown from 2 places during typechecking, not conditioned via DEBUG or anything.
Also wonder why it occurs in the ParseFile test...

[auduchinok]

Also wonder why it occurs in the ParseFile test...

I've added it in #15458 to ensure that trees produced by parser recovery don't break analysis, like in #15452.

[T-Gro]

Now I see, thanks.