[5.1] Cherry-pick module interface fixes to 5.1

lib/Sema/TypeCheckAttr.cpp

@@ -415,8 +415,13 @@ void AttributeEarlyChecker::visitIBOutletAttr(IBOutletAttr *attr) {
   if (!VD->getDeclContext()->getSelfClassDecl() || VD->isStatic())
     diagnoseAndRemoveAttr(attr, diag::invalid_iboutlet);
 
-  if (!VD->isSettable(nullptr))
-    diagnoseAndRemoveAttr(attr, diag::iboutlet_only_mutable);
+  if (!VD->isSettable(nullptr)) {
+    // Allow non-mutable IBOutlet properties in module interfaces,
+    // as they may have been private(set)
+    SourceFile *Parent = VD->getDeclContext()->getParentSourceFile();
+    if (!Parent || Parent->Kind != SourceFileKind::Interface)
+      diagnoseAndRemoveAttr(attr, diag::iboutlet_only_mutable);
+  }
 
   // Verify that the field type is valid as an outlet.
   auto type = VD->getType();

lib/Serialization/Deserialization.cpp

@@ -2613,7 +2613,10 @@ class swift::DeclDeserializer {
     if (auto *overridden = ctor->getOverriddenDecl()) {
       if (!attributeChainContains<RequiredAttr>(DAttrs) ||
           !overridden->isRequired()) {
-        AddAttribute(new (ctx) OverrideAttr(SourceLoc()));
+        // FIXME: why is a convenience init considered overridden when the
+        // overriding init can't be marked overriding in source?
+        if (!overridden->isConvenienceInit())
+          AddAttribute(new (ctx) OverrideAttr(SourceLoc()));
       }
     }
 

test/ParseableInterface/convenience-init.swift

@@ -0,0 +1,51 @@
+// RUN: %empty-directory(%t)
+
+// Generate the parseable interface of the current file via the merge-modules step
+// RUN: %target-build-swift -emit-module -o %t/Test.swiftmodule -emit-parseable-module-interface-path %t/TestMerge.swiftinterface -module-name Test %s
+
+// Generate the parseable interface of the current file via a single frontend invocation
+// RUN: %target-swift-frontend -typecheck  -enable-objc-interop -emit-parseable-module-interface-path %t/TestSingle.swiftinterface -module-name Test %s
+
+// Make sure both don't add override for inits shadowing convenience initializers
+// RUN: %FileCheck --check-prefixes=CHECK,SINGLE %s < %t/TestSingle.swiftinterface
+// RUN: %FileCheck --check-prefixes=CHECK,MERGE %s < %t/TestMerge.swiftinterface
+
+// Check we can consume the interface without issue
+// RUN: %target-swift-frontend -swift-version 5 -build-module-from-parseable-interface -o %t/Test.swiftmodule %t/TestSingle.swiftinterface
+// RUN: %target-swift-frontend -swift-version 5 -build-module-from-parseable-interface -o %t/Test.swiftmodule %t/TestMerge.swiftinterface
+
+public class Base {
+  let x: Int
+  public init(x: Int) {
+    self.x = x
+  }
+  convenience public init() {
+    self.init(x: 1)
+  }
+}
+
+public class Derived: Base {
+  // MERGE: {{^}}  public init(z: Swift.Int)
+  // SINGLE: {{^}}  public init(z: Int)
+  public init(z: Int) {
+    super.init(x: z)
+  }
+  // MERGE: {{^}}  public convenience init()
+  // SINGLE: {{^}}  convenience public init()
+  convenience public init() {
+    self.init(z: 1)
+  }
+}
+
+public class Derived2: Base {
+  // CHECK: {{^}}  public init()
+  public init() {
+    super.init(x: 1)
+  }
+
+  // MERGE: {{^}}  override public convenience init(x: Swift.Int)
+  // SINGLE: {{^}}  override convenience public init(x: Int)
+  override convenience public init(x: Int) {
+    self.init()
+  }
+}

test/ParseableInterface/iboutlet-private-set.swift

@@ -0,0 +1,18 @@
+// REQUIRES: objc_interop
+
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -typecheck -enable-library-evolution -disable-objc-attr-requires-foundation-module -emit-parseable-module-interface-path %t/Foo.swiftinterface %s
+// RUN: %FileCheck %s -input-file %t/Foo.swiftinterface
+// RUN: %target-swift-frontend -build-module-from-parseable-interface %t/Foo.swiftinterface -o %t/Foo.swiftmodule
+
+// Test the interface we generate for @IBOutlet private(set) properties is
+// consumable.
+
+@objc public class MyType {}
+
+open class Bar {
+	// CHECK: @objc @IBOutlet weak public var foo: MyType! {
+	// CHECK-NEXT: get
+	// CHECK-NEXT: }
+	@IBOutlet public private(set) weak var foo: MyType!
+}