@Override
  public void visitForLoop(ForStatement stat) {
    stat.setCollectionExpression(replaceExpr(stat.getCollectionExpression()));
    stat.setLoopBlock(replace(stat.getLoopBlock()));
  }
Groovy AST visitor that allows to replace both statements and expressions.

@author Peter Niederwieser
spock-core/src/main/java/org/spockframework/compiler/ExpressionReplacingVisitorSupport.java