> The issue with templates is that you can’t really type check them at the point of definition. Instead they need to be checked each time the template is used.

> The issue with templates is that you can’t really type check them at the point of definition. Instead they need to be checked each time the template is used. > This can make compilation slow but it can also make template writing very hard because a bug might only appear when a template is instantiated with certain types. yup. templates are 'compiled' in 2 phases as follows: - without instantiation at definition time, the code itself is checked for correctness, completely ignoring the template parameters. - at instantiation time, the code is checked again to ensure that all parts depending on template parameters are valid. the 2-phase translation breaks canonical notions about compile+link, where declarations of function is sufficient to compile its use...