Unresolved external symbols (engine)

I’m trying to add a new class to my project, but the editor and vs2017 both through the same linker errors. I don’t know how to fix unresolved external symbols for the engine itself. I can compile by removing my classes though.

Is this a known problem? I couldn’t find anything specific to the engine having unresolved symbols.

1>UBrushTexture.cpp.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl FTextureReference::~FTextureReference(void)" (__imp_??1FTextureReference@@UEAA@XZ) referenced in function "public: virtual __cdecl UTexture2DDynamic::~UTexture2DDynamic(void)" (??1UTexture2DDynamic@@UEAA@XZ)

1>UBrushTexture.gen.cpp.obj : error LNK2001: unresolved external symbol "__declspec(dllimport) public: virtual __cdecl FTextureReference::~FTextureReference(void)" (__imp_??1FTextureReference@@UEAA@XZ)

Then the same thing but for symbol "__declspec(dllimport) public: __cdecl FRenderCommandFence::~FRenderCommandFence(void)"

where you able to create C++ classes in the past or is this your first attempt?

I used to be able to build, but somewhere between removing classes and adding new ones it stopped working.

Finally found the following question, but I don’t know how to mark this as a duplicate.
https://answers.unrealengine.com/questions/400832/problems-compiling-classes-that-inherit-from-textu.html

Basically some classes are marked as MinimalAPI and won’t export their symbols, and thus their symbols cannot be linked against?? I might be missing something, because that doesn’t quite make sense.