Issue persists in Xcode 11.5 and 11.6 as well.
Only solution that seems to work is to move the current file into the main folder from any of the sub-folders.
Auto code completion will work fine only for files in the main folder of the app.
Once the changes are complete in the current file, it can be moved back into the sub-folder, if needed.
Very annoying sometimes.
Amardeep_Bhatia
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