[3.0] [Import as Member] Error on convenience inits in extensions of CFTypes

include/swift/AST/DiagnosticsSema.def

@@ -2034,6 +2034,9 @@ ERROR(enumstruct_convenience_init,none,
 ERROR(nonclass_convenience_init,none,
       "convenience initializer not allowed in non-class type %0",
       (Type))
+ERROR(cfclass_convenience_init,none,
+      "convenience initializers are not supported in extensions of CF types",
+      ())
 
 ERROR(dynamic_construct_class,none,
       "constructing an object of class type %0 with a metatype value must use "

lib/Sema/TypeCheckDecl.cpp

@@ -6337,8 +6337,16 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     // extensions thereof.
     if (CD->isConvenienceInit()) {
       if (auto extType = CD->getExtensionType()) {
-        if (!extType->getClassOrBoundGenericClass() &&
-            !extType->is<ErrorType>()) {
+        auto extClass = extType->getClassOrBoundGenericClass();
+
+        // Forbid convenience inits on Foreign CF types, as Swift does not yet
+        // support user-defined factory inits.
+        if (extClass &&
+            extClass->getForeignClassKind() == ClassDecl::ForeignKind::CFType) {
+          TC.diagnose(CD->getLoc(), diag::cfclass_convenience_init);
+        }
+
+        if (!extClass && !extType->is<ErrorType>()) {
           auto ConvenienceLoc =
             CD->getAttrs().getAttribute<ConvenienceAttr>()->getLocation();
 

test/decl/init/cf-types.swift

@@ -0,0 +1,23 @@
+// RUN: %target-parse-verify-swift
+// REQUIRES: OS=macosx
+
+import CoreGraphics
+
+extension CGMutablePath {
+  public convenience init(p: Bool) { // expected-error{{convenience initializers are not supported in extensions of CF types}}
+    self.init()
+  }
+  public convenience init?(maybe: Bool) { // expected-error{{convenience initializers are not supported in extensions of CF types}}
+    self.init()
+  }
+
+  public convenience init(toss: Bool) throws { // expected-error{{convenience initializers are not supported in extensions of CF types}}
+    self.init()
+  }
+}
+
+public func useInit() {
+  let _ = CGMutablePath(p: true)
+  let _ = CGMutablePath(maybe: true)
+  let _ = try! CGMutablePath(toss: true)
+}