February 28th, 2006
While implementing conditional expressions from 2.5 we had to change the stable compiler in order to keep tests from breaking. While using stable compiler as a baseline made sense when the ast compiler was new, it is less and less true as new grammar changes are introduced.
Options include
2. Capture AST output from the stable compiler and use that explicitly in current tests instead of regenerating them every time, primarily because it allows us to change the grammar without changing the stable compiler.
In either case, AST production tests for new grammar changes could be written manually, which is less effort than fixing the stable compiler (which itself isn't really tested anyway).
Discussion by Arre, Anders L., Stuart Williams