I understand the point you are making, but C++ templates really are a uniquely disastrous programming model. They can be used to pull off neat tricks, but the way those neat tricks are done is terrible.

When a proc macro fails you get an error at the site where the macro is used, and a stack trace into the proc macro crate. You can even use tools to expand the proc macro to see what went wrong (although those aren't built in, yet).

Debugging a proc macro failure is miles and above easier than debugging template errors.

This isn't really true since concepts were introduced. Granted, you have to use them, but it makes the debugging/error messages MUCH better.