If the scanner had a mechanism to either know or guess the depth a token was at the desugar layer could do more as it would be able to use that information to intuit the scope of tokens ahead and behind of where it is. Without this there is presently no way to do some of the desugar that we would like to and it has to stay in the compiler.
If the scanner had a mechanism to either know or guess the depth a token was at the desugar layer could do more as it would be able to use that information to intuit the scope of tokens ahead and behind of where it is. Without this there is presently no way to do some of the desugar that we would like to and it has to stay in the compiler.