public void VisitCorrectlyTransformsParameterExpression()
{
IStructureService service = Substitute.For <IStructureService>();
service.TranslateType(typeof(ClassA)).Returns(typeof(ClassB));
TypeVisitor visitor = new TypeVisitor(service)
{
TypeVerifiers = new ITypeVerifier[0]
};
Expression input = Expression.Parameter(typeof(ClassA));
Expression expected = Expression.Parameter(typeof(ClassB));
Expression actual = visitor.Visit(input);
AssertAreEqualExpressions(expected, actual);
}
protected override Expression VisitParameter(ParameterExpression node)
{
_structureService.VerifyType(node.Type, TypeVerifiers);
// To preserve the referential equality of parameter expressions
// the function must return the exact same output for the same input.
// Not doing this would result in the expression not being compile-able.
if (!_variableCache.ContainsKey(node))
{
Random random = new Random();
Type translatedType = _structureService.TranslateType(node.Type);
ParameterExpression newParameter = Expression.Parameter(translatedType, random.Next().ToString());
_variableCache.Add(node, newParameter);
return(newParameter);
}
return(_variableCache[node]);
}
