"Use of undeclared type" in Swift, even though type is internal, and exists in same module


I have a type in my module:

import Cocoa

class ColoredDotView : NSView {

It is used in a number of different classes with no issue:

class EditSubjectPopoverController : NSObject {

    @IBOutlet internal var subjectColorDotView : ColoredDotView!

But for some reason, when I use it in one specific class, I have compilation errors on the type:

class EditTaskPopoverController : NSObject {

    @IBOutlet internal var lowPriorityDotView : ColoredDotView! // Error here
    @IBOutlet internal var medPriorityDotView : ColoredDotView! // And here...
    @IBOutlet internal var highPriorityDotView : ColoredDotView! // And here...

The compilation error is:

EditTaskPopoverController.swift:15:49: Use of undeclared type 'ColoredDotView'

Which I don't understand. It's the first compilation error in the file, and the rest of the errors are all symptomatic of the first. Further, there are no other files with compilation errors. I don't understand why the type is undeclared, as the file is in the same module:

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I have tried cleaning the project, cleaning the build folder, and restarting Xcode, to no avail. What potential missteps can cause an undeclared type compiler error in Swift?

This question is tagged with xcode swift

~ Asked on 2014-08-22 00:22:41

The Best Answer is


For me, I encountered this error when my test target did not have some swift files that my app build target had in compile sources. It was very confusing because the 'undeclared type' was being used in so many other places with no problem, and the error seemed vague. So solution there was of course to add the file containing the 'undeclared type' to the test target.

~ Answered on 2014-11-19 23:15:40


This has already been answered by @Craig Otis, but the issue is caused when the classes in question do not belong to the same targets, usually the test target is missing. Just make sure the following check boxes are ticked.

target membership


To see the target membership. Select your file then open the file inspector (? + ? + 1) [option] + [command] + 1

detailed description

~ Answered on 2015-06-09 15:59:53

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