Merge pull request swiftlang#74398 from xymus/cross-import-public-api-use

Sema: track use in API of declaring and bystanders modules for cross-import overlays

Author: xymus

lib/AST/Module.cpp

@@ -2716,6 +2716,26 @@ void SourceFile::registerAccessLevelUsingImport(
     ImportsUseAccessLevel[mod] = accessLevel;
   else
     ImportsUseAccessLevel[mod] = std::max(accessLevel, known->second);
+
+  // Also register modules triggering the import of cross-import overlays.
+  auto declaringMod = mod->getDeclaringModuleIfCrossImportOverlay();
+  if (!declaringMod)
+    return;
+
+  SmallVector<Identifier, 1> bystanders;
+  auto bystandersValid =
+    mod->getRequiredBystandersIfCrossImportOverlay(declaringMod, bystanders);
+  if (!bystandersValid)
+    return;
+
+  for (auto &otherImport : *Imports) {
+    auto otherImportMod = otherImport.module.importedModule;
+    auto otherImportModName = otherImportMod->getName();
+    if (otherImportMod == declaringMod ||
+        llvm::find(bystanders, otherImportModName) != bystanders.end()) {
+      registerAccessLevelUsingImport(otherImport, accessLevel);
+    }
+  }
 }
 
 bool HasImportsMatchingFlagRequest::evaluate(Evaluator &evaluator,

test/CrossImport/access-level-imports-errors.swift

@@ -4,11 +4,15 @@
 // RUN: cp -r %S/Inputs/lib-templates/* %t/
 // RUN: split-file --leading-lines %s %t
 
+//--- SomeUnrelatedModule.swift
+// RUN: %target-swift-emit-module-interface(%t/lib/swift/SomeUnrelatedModule.swiftinterface) %t/SomeUnrelatedModule.swift -module-name SomeUnrelatedModule
+
 //--- BothPublic.swift
-// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/BothPublic.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/BothPublic.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
 
 public import DeclaringLibrary
 public import BystandingLibrary
+public import SomeUnrelatedModule // expected-warning {{public import of 'SomeUnrelatedModule' was not used in public declarations or inlinable code}}
 
 public func fn(_: OverlayLibraryTy) {}
 
@@ -28,7 +32,7 @@ public func fn(_: OverlayLibraryTy) {}
 // RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/FirstHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
 
 internal import DeclaringLibrary
-public import BystandingLibrary // expected-warning {{public import of 'BystandingLibrary' was not used in public declarations or inlinable code}}
+public import BystandingLibrary
 
 public func fn(_: OverlayLibraryTy) {}
 // expected-error @-1 {{function cannot be declared public because its parameter uses an internal type}}
@@ -38,7 +42,7 @@ public func fn(_: OverlayLibraryTy) {}
 //--- SecondHidden.swift
 // RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/SecondHidden.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
 
-public import DeclaringLibrary // expected-warning {{public import of 'DeclaringLibrary' was not used in public declarations or inlinable code}}
+public import DeclaringLibrary
 internal import BystandingLibrary
 
 public func fn(_: OverlayLibraryTy) {}
@@ -66,3 +70,11 @@ private import BystandingLibrary
 internal func fn(_: OverlayLibraryTy) {}
 // expected-error @-1 {{function cannot be declared internal because its parameter uses a private type}}
 // expected-note @-2 {{struct 'OverlayLibraryTy' is imported by this file as 'private' from '_OverlayLibrary'}}
+
+
+//--- UnusedOverlay.swift
+// RUN: %target-swift-emit-module-interface(%t.swiftinterface) %t/UnusedOverlay.swift -enable-cross-import-overlays -I %t/lib/swift -module-name ClientLibrary -verify
+
+public import DeclaringLibrary // expected-warning {{public import of 'DeclaringLibrary' was not used in public declarations or inlinable code}}
+public import BystandingLibrary // expected-warning {{public import of 'BystandingLibrary' was not used in public declarations or inlinable code}}
+public import SomeUnrelatedModule // expected-warning {{public import of 'SomeUnrelatedModule' was not used in public declarations or inlinable code}}