I started getting this immediately upon installing vs2015 due to a licensing disagreement w/ MS , which I lost. :-(
Freshly back to work, i encounter this issue.
I tried doing the NUGET suggested by Brien King. Problem persisted.
I tried doing the KN suggested by Teodor Constantinescu. Problem persisted.
I tried a new trivial web app and things were fine, so I did not uninstall vs2013 or vs2015.
I chose to back up my project (3 times, once on a usb stick i put in the other room) and delete groups of files and compile after each group was pulled out.
Ultimately, when I got close to the end (nearly an empty project) it compiled.
By adding groups of files back, I identified the single file that causes this issue. I can recreate the issue by uncommenting a single line.
Further commenting out code, I isolated the problem to 4 lines of code. Beautiful.
Explanation is this...
I have 2 web references that reference ssrs
THese are currently defined in my project as
SSRS_reportservice2010
and SSRS_ReportExecution2005
I struggled getting these to work, so over time i had different names as i deleted and readded the web references. (Padawan)
For whatever reason, a file that was EXCLUDED, got INCLUDED today (2013--> 2015 issue, or greg mouse farting issue? we will never know)
In that (mistakenly included) file, there was a pair of old references
'1 Imports SSRS_ReportingService2010
'2 Imports SSRS = SSRS_ReportingService2010
'3 Imports SSRS_ReportExecution
'4 Imports SSRS_E = SSRS_ReportExecution
Line 1 used to reference the WS now named in my app as SSRS_reportservice2010
You can unComment that and things compile and run. Note that you do get a warning that you are referencing an empty namespace.
Line 2 is of course an alias to the long name, because I am an extremely lazy typer, plus I insist my code be readable and long names stink IMHO.
Line 2, if uncommented , cause vbc error -2146232797
Note that uncommenting 2 , or 1 & 2 cause the error. Its something about the bad alias that causes compiler upchuck.
Repeat the above discussion with lines 3 and 4 which have to do with the webservice currenlty named SSRS_ReportExecution2005
So there you have it.
This took me 8 hours to debug. hope it helps someone.
Many of the other posts, comments, etc also mention Import/Using Statements. The root bug probably lies somewhere in there.... (yes, this is a bug in the compiler)
PS - one thing that was interesting is that the offending file's name started w/ a W so was one of the first to come out.
Nothing improved when I took that file out of the project all together.
I can not explain why the app did not compile as soon as I took the offending file out.
I can offer that I took the webservices out very late in the process, I just didnt think they were the issue.
It baffles me that the file could be gone and I was still getting the issue when I can now simply comment out 4 lines and things work perfectly.