src/share/classes/com/sun/tools/javac/comp/Check.java

*** 1601,1610 ****
--- 1601,1626 ----
              }
          }
          return false;
      }
  
+     /**
+      * Check that a resource is a valid arm resource (e.g. the resource type must be
+      * a subtype of java.lang.autoCloseable).
+      *
+      * @param resource resource tree
+      */
+     void checkArmResource(JCTree resource) {
+         if (types.asSuper(resource.type, syms.autoCloseableType.tsym) == null) {
+             typeError(resource.pos(),
+                     diags.fragment("arm.not.applicable.to.type"),
+                     resource.type,
+                     syms.autoCloseableType);
+             resource.type = types.createErrorType(resource.type);
+         }
+     }
+ 
      /** Check that a given method conforms with any method it overrides.
       *  @param tree         The tree from which positions are extracted
       *                      for errors.
       *  @param m            The overriding method.
       */