migrator: rename a property declaration if the framework property it overrides has been renamed.

lib/Migrator/APIDiffMigratorPass.cpp

@@ -1404,6 +1404,19 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
         D->walk(Removal);
       }
     }
+
+    // Handle property overriding migration.
+    if (auto *VD = dyn_cast<VarDecl>(D)) {
+      for (auto *Item: getRelatedDiffItems(VD)) {
+        if (auto *CD = dyn_cast<CommonDiffItem>(Item)) {
+          // If the overriden property has been renamed, we should rename
+          // this property decl as well.
+          if (CD->isRename() && VD->getNameLoc().isValid()) {
+            Editor.replaceToken(VD->getNameLoc(), CD->getNewName());
+          }
+        }
+      }
+    }
     return true;
   }
 };

test/Migrator/Inputs/API.json

@@ -539,5 +539,16 @@
     "RightUsr": "",
     "RightComment": "FontWeighting",
     "ModuleName": "Cities"
-  }
+  },
+  {
+    "DiffItemKind": "CommonDiffItem",
+    "NodeKind": "Var",
+    "NodeAnnotation": "Rename",
+    "ChildIndex": "0",
+    "LeftUsr": "s:6CitiesAAC6yogurtSivp",
+    "LeftComment": "yogurt",
+    "RightUsr": "",
+    "RightComment": "cheese",
+    "ModuleName": "Cities"
+  },
 ]

test/Migrator/Inputs/Cities.swift

@@ -9,6 +9,7 @@ open class Cities {
   open func buderim() -> Cities? { return Cities(x: 1) }
   open func noosa() -> [[String : Cities]?] { return [] }
   open func maroochy(x: Int?, y: Int?) {}
+  open var yogurt: Int { return 1 }
   public struct CityKind {
     public static let Town = 1
     public static let Village = 1

test/Migrator/rename-func-decl.swift

@@ -18,3 +18,7 @@ class MySubTopLevelType: ToplevelType {
 class MySubTopLevelType2: ToplevelType {
   override func member(_ x: @escaping (((([(Any)])?))) -> Void) {}
 }
+
+class SubCities: Cities {
+  override var yogurt: Int { return 2 }
+}

test/Migrator/rename-func-decl.swift.expected

@@ -18,3 +18,7 @@ class MySubTopLevelType: ToplevelType {
 class MySubTopLevelType2: ToplevelType {
   override func member(_ x: @escaping (((([(Int)])?))) -> Void) {}
 }
+
+class SubCities: Cities {
+  override var cheese: Int { return 2 }
+}