Enable SE-0409 (access-level on imports) upcoming feature (#1183)

Author: d-ronnqvist

Package.swift

@@ -17,6 +17,7 @@ let swiftSettings: [SwiftSetting] = [
 
     .enableUpcomingFeature("ConciseMagicFile"), // SE-0274: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0274-magic-file.md
     .enableUpcomingFeature("ExistentialAny"), // SE-0335: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0335-existential-any.md
+    .enableUpcomingFeature("InternalImportsByDefault"), // SE-0409: https://github.com/swiftlang/swift-evolution/blob/main/proposals/0409-access-level-on-imports.md
 ]
 
 let package = Package(

Sources/SwiftDocC/Benchmark/Benchmark.swift

@@ -8,7 +8,7 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
+public import Foundation
 
 /// A logger that runs benchmarks and stores the results.
 public class Benchmark: Encodable {

Sources/SwiftDocC/Benchmark/BenchmarkResults.swift

@@ -8,7 +8,7 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
+public import Foundation
 
 /// The results of a single benchmark run.
 public struct BenchmarkResults: Codable {

Sources/SwiftDocC/Benchmark/Metrics/Duration.swift

@@ -8,7 +8,7 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
+public import Foundation
 
 extension Benchmark {
     /// A duration metric in milliseconds.

Sources/SwiftDocC/Benchmark/Metrics/OutputSize.swift

@@ -8,7 +8,7 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
+public import Foundation
 
 extension Benchmark {
     /// Measures the total output size of a DocC archive.

Sources/SwiftDocC/Catalog Processing/GeneratedCurationWriter.swift

@@ -8,7 +8,7 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
+public import Foundation
 import SymbolKit
 
 /// A type that writes the auto-generated curation into documentation extension files.

Sources/SwiftDocC/Checker/Checker.swift

@@ -8,7 +8,7 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Markdown
+public import Markdown
 
 /**
  A markup checker.

Sources/SwiftDocC/Checker/Checkers/AbstractContainsFormattedTextOnly.swift

@@ -8,8 +8,8 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-import Markdown
+public import Foundation
+public import Markdown
 
 /**
  A document's abstract may only contain formatted text. Images and links are not allowed.

Sources/SwiftDocC/Checker/Checkers/DuplicateTopicsSection.swift

@@ -8,8 +8,8 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-import Markdown
+public import Foundation
+public import Markdown
 
 /**
  A `Document` may only have one level-2 "Topics" heading at the top level, since it serves as structured data for a documentation bundle's hierarchy.

Sources/SwiftDocC/Checker/Checkers/InvalidAdditionalTitle.swift

@@ -8,8 +8,8 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-import Markdown
+public import Foundation
+public import Markdown
 
 /**
  A document should have a single title, i.e. a single first-level heading.