Ignore fixits for adding objc(selector) when doing migration, and fixits for mismatch label in overridden method (#2734)

* [FixCode] Follow-up for b4a2b53, ignore another diagnostic fixit that is messing with argument labels.

* [FixCode] When picking-up fixits for migration ignore the fixits for adding @objc(selector).

These interact badly with the swift migrator, they are triggered by label mismatches in pre-migrated code.

We also don't generally need them since we do inference for the most common cases.

Author: akyrtzi

lib/FrontendTool/FrontendTool.cpp

@@ -560,7 +560,13 @@ class JSONFixitWriter : public DiagnosticConsumer {
     // The following interact badly with the swift migrator, they are undoing
     // migration of arguments to preserve the no-label for first argument.
     if (Info.ID == diag::witness_argument_name_mismatch.ID ||
-      Info.ID == diag::missing_argument_labels.ID)
+      Info.ID == diag::missing_argument_labels.ID ||
+      Info.ID == diag::override_argument_name_mismatch.ID)
+      return false;
+    // This also interacts badly with the swift migrator, it unnecessary adds
+    // @objc(selector) attributes triggered by the mismatched label changes.
+    if (Info.ID == diag::objc_witness_selector_mismatch.ID ||
+        Info.ID == diag::witness_non_objc.ID)
       return false;
 
     if (Kind == DiagnosticKind::Error)

test/FixCode/fixits-apply.swift

@@ -80,11 +80,21 @@ func ftest2(x x: Int -> Int) {}
 protocol SomeProt {
   func protMeth(p: Int)
 }
-class Test2 : SomeProt {
+@objc protocol SomeObjCProt {
+  func objcprotMeth(p: Int)
+}
+class Test2 : SomeProt, SomeObjCProt {
   func protMeth(_ p: Int) {}
 
   func instMeth(p: Int) {}
   func instMeth2(p: Int, p2: Int) {}
+  func objcprotMeth(_ p: Int) {}
+}
+@objc class Test3 : SomeObjCProt {
+  func objcprotMeth(_ p: Int) {}
+}
+class SubTest2 : Test2 {
+  override func instMeth(_ p: Int) {}
 }
 Test2().instMeth(0)
 Test2().instMeth2(0, p2:1)

test/FixCode/fixits-apply.swift.result

@@ -83,11 +83,21 @@ func ftest2(x: (Int) -> Int) {}
 protocol SomeProt {
   func protMeth(p: Int)
 }
-class Test2 : SomeProt {
+@objc protocol SomeObjCProt {
+  func objcprotMeth(p: Int)
+}
+class Test2 : SomeProt, SomeObjCProt {
   func protMeth(_ p: Int) {}
 
   func instMeth(p: Int) {}
   func instMeth2(p: Int, p2: Int) {}
+  func objcprotMeth(_ p: Int) {}
+}
+@objc class Test3 : SomeObjCProt {
+  func objcprotMeth(_ p: Int) {}
+}
+class SubTest2 : Test2 {
+  override func instMeth(_ p: Int) {}
 }
 Test2().instMeth(0)
 Test2().instMeth2(0, p2:1)