@Override
  @SuppressWarnings("unchecked")
  public void visitTupleExpression(TupleExpression expr) {
    TupleExpression conversion =
        new TupleExpression(
            // prevent each lvalue from getting turned into record(lvalue),
            // which no longer is an lvalue
            convertAllAndRecordNa(expr.getExpressions()));

    conversion.setSourcePosition(expr);
    result = recordNa(conversion);
  }
Rewrites explicit ("assert x > 3") and implicit ("x > 3") condition
statements. Replacing the original statement with the rewritten one is up
to clients.

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