[migrator] Handle renaming from explicit argument label to empty argument label at call sites. rdar://32241559 (#9873)

Author: nkcsgexi

lib/Migrator/APIDiffMigratorPass.cpp

@@ -325,6 +325,7 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
     unsigned Idx = 0;
     auto Ranges = getCallArgLabelRanges(SM, Arg,
                                         LabelRangeEndAt::LabelNameOnly);
+    llvm::SmallVector<uint8_t, 2> ToRemoveIndices;
     for (unsigned I = 0; I < Ranges.size(); I ++) {
       if (std::any_of(IgnoreArgIndex.begin(), IgnoreArgIndex.end(),
                       [I](unsigned Ig) { return Ig == I; }))
@@ -333,15 +334,24 @@ struct APIDiffMigratorPass : public ASTMigratorPass, public SourceEntityWalker {
       if (Idx < NewName.argSize()) {
         auto Label = NewName.args()[Idx++];
 
-        // FIXME: We update only when args are consistently valid.
         if (Label != "_") {
           if (LR.getByteLength())
             Editor.replace(LR, Label);
           else
             Editor.insert(LR.getStart(), (llvm::Twine(Label) + ": ").str());
+        } else if (LR.getByteLength()){
+          // New label is "_" however the old label is explicit.
+          ToRemoveIndices.push_back(I);
         }
       }
     }
+    if (!ToRemoveIndices.empty()) {
+      auto Ranges = getCallArgLabelRanges(SM, Arg,
+                                         LabelRangeEndAt::BeforeElemStart);
+      for (auto I : ToRemoveIndices) {
+        Editor.remove(Ranges[I]);
+      }
+    }
   }
 
   void handleFuncRename(ValueDecl *FD, Expr* FuncRefContainer, Expr *Arg) {

test/Migrator/API.json

@@ -39,6 +39,17 @@
     "RightComment": "barNewInstanceFunc1(newlabel1:newlabel2:newlabel3:newlabel4:)",
     "ModuleName": "bar"
   },
+  {
+    "DiffItemKind": "CommonDiffItem",
+    "NodeKind": "Function",
+    "NodeAnnotation": "Rename",
+    "ChildIndex": "0",
+    "LeftUsr": "c:objc(cs)BarForwardDeclaredClass(im)barInstanceFunc2:toRemove:toRemove1:toRemove2:",
+    "LeftComment": "",
+    "RightUsr": "",
+    "RightComment": "barNewInstanceFunc2(_:_:NotToRemove1:_:)",
+    "ModuleName": "bar"
+  },
   {
     "DiffItemKind": "CommonDiffItem",
     "NodeKind": "Constructor",

test/Migrator/mock-sdk/Bar.framework/Headers/Bar.h

@@ -14,6 +14,7 @@ int barGlobalFuncOldName(int a);
 - (id)initWithOldLabel0:(int)frame;
 - (void) barInstanceFunc0;
 - (void) barInstanceFunc1:(int)info anotherValue:(int)info1 anotherValue1:(int)info2 anotherValue2:(int)info3;
+- (void) barInstanceFunc2:(int)info toRemove:(int)info1 toRemove1:(int)info2 toRemove2:(int)info3;
 @end
 
 enum BarForwardDeclaredEnum {

test/Migrator/rename.swift

@@ -17,3 +17,7 @@ func foo(_ b: BarForwardDeclaredClass) {
   barGlobalFuncOldName(2)
   _ = barGlobalVariableOldEnumElement
 }
+
+func foo1(_ b: BarForwardDeclaredClass) {
+  b.barInstanceFunc2(0,toRemove:1,toRemove1:2,toRemove2:3)
+}

test/Migrator/rename.swift.expected

@@ -17,3 +17,7 @@ func foo(_ b: BarForwardDeclaredClass) {
   barGlobalFuncNewName(newlabel: 2)
   _ = NewEnum.enumElement
 }
+
+func foo1(_ b: BarForwardDeclaredClass) {
+  b.barNewInstanceFunc2(0,1,NotToRemove1:2,3)
+}