Sometimes we hit issues with SourceKit that cause this rule to produce
false positives of some imports. While we would prefer to fix all of
these cases whenever possible, this gives us a temporary escape hatch to
tell the rule never to remove imports of specific modules until the
fixes land in SwiftLint or Swift itself.
Currently this is for us to opt out of https://bugs.swift.org/browse/SR-13120
For example, if `CGFloat` is used in a file where only `UIKit` is imported but not `CoreGraphics`, this will be a violation even if the file previously compiled.
This is because Swift allows referencing some declarations that are only transitively imported.
Enabling the `require_explicit_imports` configuration option will require that the module of every declaration referenced in a source file be explicitly imported.
This will add significant noise to the imports list, but has a few advantages:
1. It will be easier to understand all the dependencies explicitly referenced in a source file.
2. Correcting the `unused_import` rule will no longer introduce compilation errors in files that compiled prior to the correction.
If missing imports are added to a file when correcting it, the `sorted_imports` rule will be automatically run on that file.
If you with to allow some imports to be implicitly importable transitively, you may specify the `allowed_transitive_imports` configuration:
```yaml
unused_import:
require_explicit_imports: true
allowed_transitive_imports:
- module: Foundation
allowed_transitive_imports:
- CoreFoundation
- Darwin
- ObjectiveC
```
JP Simard
Keith Smiley