The way I read Alan's earlier mail is precisely that; auto-generated Show does what he wants (show the entire AST), whereas Outputable hides too much information. I very much understand his frustration with having to manually figure out what constructors and datatypes go where in a compiled program. Alan's point was the *absence* of auto derived Show instances and, in the case of SrcSpan, too much verbosity (rather than wanting stuff to be incomplete).

Allowing some bespoke stuff to reduce the noise of something like record field names for SrcSpan makes even more sense in this context. Similarly, this is why Alan & I want everything to have Data instances, so you can (amongst many other nice things) selectively print parts of the AST.

Ph.