Fix a crash in BanNashorn

PiperOrigin-RevId: 441076150

Author: cushon

check_api/src/main/java/com/google/errorprone/util/ASTHelpers.java

@@ -1160,15 +1160,22 @@ public static ClassSymbol enclosingClass(Symbol sym) {
   }
 
   /** Return the enclosing {@code PackageSymbol} of the given symbol, or {@code null}. */
+  @Nullable
   public static PackageSymbol enclosingPackage(Symbol sym) {
-    return sym.packge();
+    Symbol curr = sym;
+    for (; curr != null && curr.owner != null; curr = curr.owner) {
+      if (curr.getKind().equals(ElementKind.PACKAGE)) {
+        return (PackageSymbol) curr;
+      }
+    }
+    return null;
   }
 
   /** Return true if the given symbol is defined in the current package. */
   public static boolean inSamePackage(Symbol targetSymbol, VisitorState state) {
     JCCompilationUnit compilationUnit = (JCCompilationUnit) state.getPath().getCompilationUnit();
     PackageSymbol usePackage = compilationUnit.packge;
-    PackageSymbol targetPackage = targetSymbol.packge();
+    PackageSymbol targetPackage = enclosingPackage(targetSymbol);
 
     return targetPackage != null
         && usePackage != null