[Basic] Extract isEditorPlaceholder from Identifier to standalone function

Author: ahoppen

include/swift/AST/Identifier.h

@@ -17,6 +17,7 @@
 #ifndef SWIFT_AST_IDENTIFIER_H
 #define SWIFT_AST_IDENTIFIER_H
 
+#include "swift/Basic/EditorPlaceholder.h"
 #include "swift/Basic/LLVM.h"
 #include "llvm/ADT/FoldingSet.h"
 #include "llvm/ADT/PointerUnion.h"
@@ -125,7 +126,7 @@ class Identifier {
   }
 
   static bool isEditorPlaceholder(StringRef name) {
-    return name.startswith("<#");
+    return swift::isEditorPlaceholder(name);
   }
 
   bool isEditorPlaceholder() const {

include/swift/Basic/EditorPlaceholder.h

@@ -46,6 +46,8 @@ struct EditorPlaceholderData {
 Optional<EditorPlaceholderData>
   parseEditorPlaceholder(StringRef PlaceholderText);
 
+/// Checks if an identifier with the given text is an editor placeholder
+bool isEditorPlaceholder(StringRef IdentifierText);
 } // end namespace swift
 
 #endif // SWIFT_BASIC_EDITORPLACEHOLDER_H

lib/Basic/EditorPlaceholder.cpp

@@ -78,3 +78,7 @@ swift::parseEditorPlaceholder(StringRef PlaceholderText) {
 
   return PHDataTyped;
 }
+
+bool swift::isEditorPlaceholder(StringRef IdentifierText) {
+  return IdentifierText.startswith("<#");
+}