Now I get Backtrace: In ice-9/psyntax.scm: 1259: 19 [# #f (if #f (if #f # #f) #f) #f] 1259: 18 [# #f (if #f (if #f # #f) #f) #f] 1259: 17 [# #f (if #f (if #f # #f) #f) #f] 1259: 16 [# #f (if #f (if #f # #f) #f) #f] 1259: 15 [# #f (if #f (if #f # #f) #f) #f] 1259: 14 [# #f (if #f (if #f # #f) #f) #f] 1259: 13 [# #f (if #f (if #f # #f) #f) #f] 1259: 12 [# #f (if #f (if #f # #f) #f) #f] 1259: 11 [# #f (if #f (if #f # #f) #f) #f] 1259: 10 [# #f (if #f (if #f # #f) #f) #f] 1259: 9 [# #f (if #f (if #f # #f) #f) #f] 1259: 8 [# #f (if #f (if #f # #f) #f) #f] 1257: 7 [# #f (if #f (if #f # #f) #f) #f] 1186: 6 [syntax-type (if #f (if #f (if #f # ...) ...) ...) () ...] 579: 5 [syntax-type if () ((top)) #f #f (hygiene guile-user) #t] 293: 4 [get-global-definition-hook if (hygiene guile-user)] In ice-9/boot-9.scm: 2697: 3 [# # ...] 2512: 2 [nested-ref-module # (guile-user)] 2294: 1 [module-ref-submodule # guile-user] 1925: 0 [# #] ice-9/boot-9.scm:1925:2: In procedure #: ice-9/boot-9.scm:1925:2: Throw to key `vm-error' with args `(vm-run "VM: Stack overflow" ())'. Using guile --no-auto-compile on the same file, I just get Backtrace: In ice-9/psyntax.scm: 1259: 19 Aborted (core dumped) That's the stable version of GUILE included with Ubuntu 14.04. -- David Kastrup