Indexing Unreal Engine code
You can start typing or navigating through your Unreal Engine project seconds after you open it because by default, indexing of the engine code (which constitutes the major part of a project) is performed in the background after non-engine code is parsed.
You can configure how the engine code is indexed on the Alt+R, O): you can disable the background indexing in case you want to have all engine code indexed before you start, or if you notice any performance degradation, you can disable the indexing altogether by clearing the Index Unreal Engine source files.page of ReSharper options(
When the indexing is enabled, you will have a number of features. For example, use any symbols from the engine and ReSharper will automatically add missing #includes, or find usages of engine classes — for example,
TArray<T> — in the engine's code and study how they are used there.
If the indexing is disabled, ReSharper will still index header file names, which is very fast but it will let you have code completion for includes, for example,
#include <unreal/SomeClassFromUnreal.h>. Once you include a header, its code will be indexed automatically, so you will have code completion and analysis for symbols from the included header.
ReSharper runs UnrealHeaderTool only on the file that is currently open, and the process is optimized to have a minimal impact on overall performance. You can still disable the UnrealHeaderTool integration via the Enable UnrealHeaderTool inspections option on the page of ReSharper options(Alt+R, O).