I've been looking at these slides about improving type error messages for programming languages.
One of the things they describe, starting at Slide 8, is the concept of amechanicity. Anytime the internals of a compiler, such as optimizations or de-sugaring are exposed, this is an example of mechanicity. A goal of quality error messages is to stay close to the source code, without leaking details of the compiler implementation to the programmer.
I can't find any references to this concept outside of these slides. Has anyone come across this before, particularly in a paper that would be more reliable to cite than lecture slides?