src/jdk.compiler/share/classes/com/sun/tools/javac/code/Lint.java

*** 120,129 ****
--- 120,130 ----
              }
              values.add(LintCategory.REQUIRES_TRANSITIVE_AUTOMATIC);
              values.add(LintCategory.OPENS);
              values.add(LintCategory.MODULE);
              values.add(LintCategory.REMOVAL);
+             values.add(LintCategory.FUTURE);
          }
  
          // Look for specific overrides
          for (LintCategory lc : LintCategory.values()) {
              if (options.isSet(Option.XLINT_CUSTOM, lc.option)) {
*** 283,292 ****
--- 284,299 ----
           * Warn about unchecked operations on raw types.
           */
          UNCHECKED("unchecked"),
  
          /**
+          * Warn about source structures that may be illegal or
+          * questionable in future source versions.
+          */
+         FUTURE("future"),
+ 
+         /**
           * Warn about potentially unsafe vararg methods
           */
          VARARGS("varargs");
  
          LintCategory(String option) {