What are the limitations of SFINAE in C++?

What are the limitations of SFINAE in C++?

SFINAE, or Substitution Failure Is Not An Error, has several limitations. One major limitation is that it can lead to complex and hard-to-read code, especially when used extensively. Additionally, SFINAE only works with template parameters, so it cannot be applied to non-template functions or classes.

Can you give an example of where SFINAE might fail?

Sure! One common issue is when trying to use SFINAE to differentiate between types that have similar signatures. For instance, if you have two overloaded functions that differ only by const-ness, SFINAE might not be able to resolve which one to use, leading to ambiguity.

Are there alternatives to SFINAE?

Yes, alternatives include concepts (introduced in C++20), which provide a more readable way to enforce constraints on template parameters. Another option is using static assertions to check conditions at compile time.

How does SFINAE compare to concepts?

SFINAE is more complex and can lead to less readable code, while concepts provide clearer syntax and better error messages, making it easier to understand template constraints.