Move ancestorOrSelf to SwiftSyntax module

Author: MAJKFL

Sources/SwiftBasicFormat/BasicFormat.swift

@@ -676,17 +676,3 @@ fileprivate extension TokenSyntax {
     }
   }
 }
-
-fileprivate extension SyntaxProtocol {
-  /// Returns this node or the first ancestor that satisfies `condition`.
-  func ancestorOrSelf<T>(mapping map: (Syntax) -> T?) -> T? {
-    var walk: Syntax? = Syntax(self)
-    while let unwrappedParent = walk {
-      if let mapped = map(unwrappedParent) {
-        return mapped
-      }
-      walk = unwrappedParent.parent
-    }
-    return nil
-  }
-}

Sources/SwiftParserDiagnostics/SyntaxExtensions.swift

@@ -119,18 +119,6 @@ extension SyntaxProtocol {
     }
   }
 
-  /// Returns this node or the first ancestor that satisfies `condition`.
-  func ancestorOrSelf<T>(mapping map: (Syntax) -> T?) -> T? {
-    var walk: Syntax? = Syntax(self)
-    while let unwrappedParent = walk {
-      if let mapped = map(unwrappedParent) {
-        return mapped
-      }
-      walk = unwrappedParent.parent
-    }
-    return nil
-  }
-
   /// Returns `true` if the next token's leading trivia should be made leading trivia
   /// of this mode, when it is switched from being missing to present.
   var shouldBeInsertedAfterNextTokenTrivia: Bool {

Sources/SwiftSyntax/SyntaxProtocol.swift

@@ -186,7 +186,7 @@ extension SyntaxProtocol {
   }
 }
 
-// MARK: Children / parent
+// MARK: Children / parent / ancestor
 
 extension SyntaxProtocol {
   /// A sequence over the children of this node.
@@ -238,6 +238,18 @@ extension SyntaxProtocol {
   public var previousToken: TokenSyntax? {
     return self.previousToken(viewMode: .sourceAccurate)
   }
+
+  /// Returns this node or the first ancestor that satisfies `condition`.
+  public func ancestorOrSelf<T>(mapping map: (Syntax) -> T?) -> T? {
+    var walk: Syntax? = Syntax(self)
+    while let unwrappedParent = walk {
+      if let mapped = map(unwrappedParent) {
+        return mapped
+      }
+      walk = unwrappedParent.parent
+    }
+    return nil
+  }
 }
 
 // MARK: Accessing tokens