NameTranslation: ensure that preferred names are preferred to implicit names in @objc(). rdar://30658589 (#7692)

Implicit names in @objc() are essentially cached auto-translated Swift names. This patch ensures that we don't mistake them for explicitly specified objc selectors.

Author: nkcsgexi

lib/AST/Decl.cpp

@@ -3375,14 +3375,31 @@ void AbstractStorageDecl::setInvalidBracesRange(SourceRange BracesRange) {
   GetSetInfo.setPointer(getSetInfo);
 }
 
+static Optional<ObjCSelector>
+getNameFromObjcAttribute(const ObjCAttr *attr, DeclName preferredName) {
+  if (!attr)
+    return None;
+  if (auto name = attr->getName()) {
+    if (attr->isNameImplicit()) {
+      // preferredName > implicit name, because implicit name is just cached
+      // actual name.
+      if (!preferredName)
+        return *name;
+    } else {
+      // explicit name > preferred name.
+      return *name;
+    }
+  }
+  return None;
+}
+
 ObjCSelector AbstractStorageDecl::getObjCGetterSelector(
                LazyResolver *resolver, Identifier preferredName) const {
   // If the getter has an @objc attribute with a name, use that.
   if (auto getter = getGetter()) {
-    if (auto objcAttr = getter->getAttrs().getAttribute<ObjCAttr>()) {
-      if (auto name = objcAttr->getName())
+      if (auto name = getNameFromObjcAttribute(getter->getAttrs().
+          getAttribute<ObjCAttr>(), preferredName))
         return *name;
-    }
   }
 
   // Subscripts use a specific selector.
@@ -3414,9 +3431,8 @@ ObjCSelector AbstractStorageDecl::getObjCSetterSelector(
   auto setter = getSetter();
   auto objcAttr = setter ? setter->getAttrs().getAttribute<ObjCAttr>()
                          : nullptr;
-  if (objcAttr) {
-    if (auto name = objcAttr->getName())
-      return *name;
+  if (auto name = getNameFromObjcAttribute(objcAttr, DeclName(preferredName))) {
+    return *name;
   }
 
   // Subscripts use a specific selector.
@@ -3445,7 +3461,7 @@ ObjCSelector AbstractStorageDecl::getObjCSetterSelector(
   auto result = VarDecl::getDefaultObjCSetterSelector(ctx, Name);
 
   // Cache the result, so we don't perform string manipulation again.
-  if (objcAttr)
+  if (objcAttr && preferredName.empty())
     const_cast<ObjCAttr *>(objcAttr)->setName(result, /*implicit=*/true);
 
   return result;
@@ -4228,10 +4244,9 @@ SourceRange AbstractFunctionDecl::getSignatureSourceRange() const {
 ObjCSelector AbstractFunctionDecl::getObjCSelector(
                LazyResolver *resolver, DeclName preferredName) const {
   // If there is an @objc attribute with a name, use that name.
-  auto objc = getAttrs().getAttribute<ObjCAttr>();
-  if (objc) {
-    if (auto name = objc->getName())
-      return *name;
+  auto *objc = getAttrs().getAttribute<ObjCAttr>();
+  if (auto name = getNameFromObjcAttribute(objc, preferredName)) {
+    return *name;
   }
 
   auto &ctx = getASTContext();
@@ -4357,7 +4372,7 @@ ObjCSelector AbstractFunctionDecl::getObjCSelector(
 
   // If we did any string manipulation, cache the result. We don't want to
   // do that again.
-  if (didStringManipulation && objc)
+  if (didStringManipulation && objc && !preferredName)
     const_cast<ObjCAttr *>(objc)->setName(result, /*implicit=*/true);
 
   return result;

test/SourceKit/NameTranslation/swiftnames.swift

@@ -47,6 +47,10 @@ func takeError(_ e : CustomError) {
 @objc(C2ObjC)
 class C2 {}
 
+@objc open class /*MyClass*/MyClass: NSObject {
+  @objc open func /*MyClass_foo*/foo(/*MyClass_foo_p1*/bar: Int, /*MyClass_foo_p2*/baz: Int) {}
+}
+
 // REQUIRES: objc_interop
 // RUN: %sourcekitd-test -req=translate -swift-name "foo(a:b:c:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK1 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "foo(a1:b1:c1:)" -pos=11:11 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK2 %s
@@ -68,6 +72,7 @@ class C2 {}
 // RUN: %sourcekitd-test -req=translate -swift-name "a2" -pos=41:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK14 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "A2" -pos=41:10 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK14 %s
 // RUN: %sourcekitd-test -req=translate -swift-name "C3" -pos=48:8 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK15 %s
+// RUN: %sourcekitd-test -req=translate -swift-name "bar(_:other:)" -pos=51:36 %s -- -F %S/Inputs/mock-sdk -I %t.tmp %mcp_opt %s | %FileCheck -check-prefix=CHECK16 %s
 
 // CHECK-NONE: <empty name translation info>
 // CHECK1: fooWithA:b:c:
@@ -86,3 +91,4 @@ class C2 {}
 // CHECK13: CommonFixA2
 // CHECK14: CustomErrorA2
 // CHECK15: C2ObjC
+// CHECK16: bar:other: