Visual Studio 2015 or 2017 shows IntelliSense errors but solution compiles

Question

We are currently evaluating the new Visual Studio 2015 and encountered a strange problem with IntelliSense. When I compiled our main solution with the new studio the build succeeds, but nevertheless 6 errors are shown.

I discovered that it's not a real error, but only an intellisense error. The code is definitely correct and everything compiled successfully. The code however is marked red and errors show up in the error list.

All 6 errors have the same origin. It's a simple constructor call. Strange enough, but there are also some occurrences of the exact same constructor without any errors.

The error message:

Code: CS1729
Message: '<the class>' does not contain a constructor that takes that many arguments.
Project: <the project name>
File: <the path to the file>

The new studio was installed on a freshly installed Windows 7 without any legacy software (no VS13).

I've already tried to clear the caches, deleted the suo file, deleted bin and obj directories, cleaned and rebuilt the solution etc. But nothing worked.

Can anyone explain that behavior to me?

Solution 1

Also had this problem with a migrated project, so I referenced the Microsoft.CSharp dll. In some projects I needed to remove and add again the Reference in the project.

Solution 2

I had thousands of intellisense errors and 0 build errors. After deleting .suo file and restarting VS intellisense errors are gone.

Suo file is located relatively to source in: .vs\SolutionName\v14\.suo

According to comment: Beware that *.suo is a hidden file.

Edit: According to comments, VS2017 has the same issue, so you can use similar solution: Delete .vs\SolutionName\v15\.suo

Solution 3

Ran into similar issue in Visual Studio 2017 ASP.Net Core Project. Following steps did the trick for me

1. Perform Clean Solution
2. Close VS
3. Delete .suo file & Delete bin/obj directories
4. Reopen VS

Solution 4

Similar problem as others, but different resolution. Posting in case I can help someone else.

Running Visual Studio 2017 15.5.2. I use Git and frequently switch branches. Several weeks ago, I started having editors show me errors (all related to types it could not find even though references were valid). Compile worked great. I confirmed the same issue in VS 2017 15.6 Preview (Jan 6, 2018). I would try to delete cache, SUO files, or bin/obj folders and no impact. At first it would appear to work. Reopen Visual Studio and everything would look good. Use "Rebuild Solution" and the IntelliSense errors would returns. I even tried uninstall/reinstall of Visual Studio.

I had the same issue on two machines, both with same version of Visual Studio.

By looking at the errors about missing types, they all appeared to come from two referenced projects. One of those references was a shared project used by just about every other project in the solution, but one of them was a small project without many references. It just so happens that the small project was also referenced by my larger shared project. In Visual Studio, I unloaded the small project and reloaded it. The errors went away! They errors did not come back on Rebuild Solution.

I then switched Git branches and the errors all came back. Fortunately I repeated the above steps of unloading/reloading the small project and the errors went away.

Every time I switch Git branches, the errors come back until I repeat that process. There are zero changes between the Git branches for the smaller project that I unload/reload. Unclear why that sequence is fixing my issue.

Solution 5

Also had this problem (the title, not the specific error message), as well as squiggly lines in the editor. The first squiggly line is under the first #include statement, which names a precompiled header. Intellisense fails to include the precompiled header, but doesn't list that as an error; instead it lists errors further down the file, on code that (very rightfully) relies on declarations in the precompiled header.

The reason Intellisense doesn't find the precompiled header in my environment is that the header named is not an actual file. It doesn't have to be in any other VC or gcc version I used, nor in the 2015 compiler, as long as the precompiled header settings are correctly configured. Apparently not any more for Intellisense. I'm not entirely sure it was different in 2013, maybe I just never noticed.

In the unlikely case that this would be the problem reported here, the solution is simple: create a small file with the pretend-name of the precompiled header, as specified in #include directives, and let that file include the actual name of the precompiled header.

If you wonder... why this distinction between the precompiled header name in the '#include' statement and the actual filename of the precompiled header? Precisely because it guarantees that precompiled header settings are correctly configured. Wherever a precompiled header is "#included", there is no file around that could be included. Either an actually precompiled (binary) version of the actual header is read, or the compilation fails. Obviously, a disadvantage is that it confuses people reading the code, not just Intellisense.

View more solutions

Comments

[Athafoud]

Just a note: *.suo files may be hidden in some cases. So you need to enable the View Hidden files option from windows explorer.

[Bill]

I had to do this when a team member added a new project to the solution and migrated some cs files from an existing project to the new one. When I got latest, I saw many errors but I could compile and run. Dropping and re-adding the reference to the new project from the offended project worked for me.

[Peter Macej]

Exactly the same situation that Bill described happened to us. Some classes were moved to a new project. It seems like Visual Studio didn't update it's Intellisense cache when new project reference was imported from the source control. Re-entering the reference manually forced VS to do so.

[Holger Böhnke]

Killing the .suo had no effect for me, but deleting the bin and obj dir and then rebuilding the solution did it.

[Tim]

Deleting the .suo file did not solve the problem for me (in VS2015) I am getting the spurious red squiggly in javascript that references properties from code-behind: <%=Foo%> saying the variable is not declared, but everything works at runtime.

[Geordie]

I'm not 100% sure, but this could also have fixed invalid markup errors I was getting with XAML

[nawfal]

This works but such a tedious thing to do time to time. I always have this problem when building in release mode. Strange VS cant figure it out by itself.

[Derek Greer]

find . -name "*suo" -exec rm -rf {} \;

[Michael]

Solution compiles, but shows squiggly errors in some files. No errors where shown in "Release", just in Debug. Removed Microsoft.CSharp, and the errors are gone, thanks!

[user2061057]

@Michael Thanks for that tip. I have exactly the same issue. No errors in Release but a lot of errors in Debug.

[David S.]

If the class mentioned is your own code, you can just exclude then include the file that contains the class. It should trigger VS to update IntelliSense. #awfulbug

[themightylc]

Worth mentioning imo: I had this exact problem in VS 2017 with a Visual Basic Project. I had to add the CSharp Reference, recompiled and Intellisense errors were gone. After that I could remove the reference again.

[monty]

I had a similar issue due to Resharper which needed its cache cleared.

[Erik Simonic]

Sorry to add a comment but I had same problem on vs 2017 (15.8.3 ), problem solved after delting .vs dir..

[Karel Kral]

@ErikSimonic Yes, VS 2017 is reflected in answer text also.

[Steven_BDawg]

Based off of this, I unloaded three "Test" or "Architecture" related projects, then unloaded and reloaded the Intellisense error-filled project (WPF). 0 of 0 errors :) +1 for the discrete details that led me to try something similar to you HgCoder!

[dthal]

Using VS 2017 15.9.9. Using Git. Using R#. I regularly switch branches as well. My errors are indeed all IntelliSense. I notice the unloading of the project causes the "Project" column (in the Error List tab) to go to <Unknown>. So, it does appear to be kicking it a bit. Unloading projects seems to have worked for me as well. A Clean Solution + Rebuild Solution finally yielded 0 errors.

[OpMt]

Deleting obj directory made the difference and got it to work(as bin was already empty).

[The incredible Jan]

If you have to remove and add the reference you could do it with any reference, I think. It seems to triger the rebuild of the .suo file. So deleting it is the better solution I think. Just more logical.