isUsed(expression)

    /**
     * [isUsed] and [doesParentUseChild] are defined in mutual recursion,
     * climbing up the syntax tree, passing control back and forth between the
     * two.
     *
     * Whether an expression is used is defined by the context in which it
     * appears. E.g. a "statement" in a block is considered used if it is the

forth). A Go function called by C code may take C pointers as arguments,
and it may store non-pointer data, C pointers, or Go pointers to pinned
memory through those pointers. It may not store a Go pointer to unpinned
memory in memory pointed to by a C pointer (which again, implies that it
may not store a string, slice, channel, and so forth). A Go function

You will get completion in code you might even consider impossible before. As for example, the `price` key inside a JSON body (that could have been nested) that comes from a request.

No more typing the wrong key names, coming back and forth between docs, or scrolling up and down to find if you finally used `username` or `user_name`.

### Short

import java.util.Iterator;
import javax.annotation.CheckForNull;

/**
 * A function from {@code A} to {@code B} with an associated <i>reverse</i> function from {@code B}
 * to {@code A}; used for converting back and forth between <i>different representations of the same
 * information</i>.
 *
 * <h3>Invertibility</h3>
 *
 * <p>The reverse operation <b>may</b> be a strict <i>inverse</i> (meaning that {@code

import java.util.Iterator;
import javax.annotation.CheckForNull;

/**
 * A function from {@code A} to {@code B} with an associated <i>reverse</i> function from {@code B}
 * to {@code A}; used for converting back and forth between <i>different representations of the same
 * information</i>.
 *
 * <h3>Invertibility</h3>
 *
 * <p>The reverse operation <b>may</b> be a strict <i>inverse</i> (meaning that {@code

  }

  /*
   * Now we have monster tests that create hundreds of Orderings using different
   * combinations of methods, then checks compare(), binarySearch() and so
   * forth on each one.
   */

  // should periodically try increasing this, but it makes the test run long
  private static final int RECURSE_DEPTH = 2;

  public void testCombinationsExhaustively_startingFromNatural() {

  }

  /*
   * Now we have monster tests that create hundreds of Orderings using different
   * combinations of methods, then checks compare(), binarySearch() and so
   * forth on each one.
   */

  // should periodically try increasing this, but it makes the test run long
  private static final int RECURSE_DEPTH = 2;

  public void testCombinationsExhaustively_startingFromNatural() {

America/Metlakatla America/Mexico_City America/Miquelon America/Moncton America/Monterrey America/Montevideo America/Montreal America/Montserrat America/Nassau America/New_York America/Nipigon America/Nome America/Noronha America/North_Dakota/Beulah America/North_Dakota/Center America/North_Dakota/New_Salem America/Nuuk America/Ojinaga America/Panama America/Pangnirtung America/Paramaribo America/Phoenix America/Port-au-Prince America/Port_of_Spain America/Porto_Acre America/Porto_Velho America/Puerto_Rico...

  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;

  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;
  private final @Nullable Integer numElements;