[FixCode] Apply #selector fixits

These are very useful fixits for migration. Note: this applies the
fixits for selectors that are actually found, but not the one that wraps
an arbitrary string literal in Selector(...), because that one indicates
a possibly missing selector that the user should review.

rdar://problem/26678232

lib/FrontendTool/FrontendTool.cpp

@@ -595,7 +595,9 @@ private:
         Info.ID == diag::function_type_no_parens.ID ||
         Info.ID == diag::convert_let_to_var.ID ||
         Info.ID == diag::parameter_extraneous_double_up.ID ||
-        Info.ID == diag::attr_decl_attr_now_on_type.ID)
+        Info.ID == diag::attr_decl_attr_now_on_type.ID ||
+        Info.ID == diag::selector_construction_suggest.ID ||
+        Info.ID == diag::selector_literal_deprecated_suggest.ID)
       return true;
     return false;
   }

test/FixCode/fixits-apply-selector.swift

@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-objc-attr-requires-foundation-module -parse %s -emit-fixits-path %t.remap
+// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
+import ObjectiveC
+
+// REQUIRES: objc_interop
+
+@objc class Selectors {
+  func takeSel(_: Selector) {}
+  func mySel() {}
+  func test() {
+    takeSel("mySel")
+    takeSel(Selector("mySel"))
+  }
+}

test/FixCode/fixits-apply-selector.swift.result

@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -disable-objc-attr-requires-foundation-module -parse %s -emit-fixits-path %t.remap
+// RUN: c-arcmt-test %t.remap | arcmt-test -verify-transformed-files %s.result
+import ObjectiveC
+
+// REQUIRES: objc_interop
+
+@objc class Selectors {
+  func takeSel(_: Selector) {}
+  func mySel() {}
+  func test() {
+    takeSel(#selector(Selectors.mySel))
+    takeSel(#selector(Selectors.mySel))
+  }
+}