makeForBody() {
    const context = this.loopContext;
    const choiceContext = this.choiceContext;
    const forkContext = this.forkContext;

    // Update state.
    if (context.updateSegments) {
      context.endOfUpdateSegments = forkContext.head;

      // `update` -> `test`
      if (context.testSegments) {
        makeLooped(this, context.endOfUpdateSegments, context.testSegments);
      }
    } else if (context.testSegments) {
      finalizeTestSegmentsOfFor(context, choiceContext, forkContext.head);
    } else {
      context.endOfInitSegments = forkContext.head;
    }

    let bodySegments = context.endOfTestSegments;

    if (!bodySegments) {
      /*
       * If there is not the `test` part, the `body` path comes from the
       * `init` part and the `update` part.
       */
      const prevForkContext = ForkContext.newEmpty(forkContext);

      prevForkContext.add(context.endOfInitSegments);
      if (context.endOfUpdateSegments) {
        prevForkContext.add(context.endOfUpdateSegments);
      }

      bodySegments = prevForkContext.makeNext(0, -1);
    }
    context.continueDestSegments = context.continueDestSegments || bodySegments;
    forkContext.replaceHead(bodySegments);
  }
Makes a code path segment for the body part of a ForStatement.
@returns {void}