Testable Import of Module Containing Internal Struct Results In Unresolved Identifier Error

I have a Unit Test Case class, as part of a Unit Test target, in which I am importing the module I wish to test with @testable.


I am unable to build and run the test because one of the structs I'm trying to create in my test function, an internally defined struct in the module under test, is reported as an unresolved identifier (when I try to instantiate one) or undeclared type (when I introduce a typealias).


Oddly, the type name appears in auto complete, but then autocomplete fails to show any initializers for the type.


Any suggestions as to what to look for?


Xcode 11.3, Swift 5