Monomorphisation panic

[sullyj3]

The code:

fizzbuzz_loop n = 
  loop (i = 1) ->

    if i % 3 == 0 and i % 5 == 0 then
      print "FizzBuzz"
    else if i % 3 == 0 then
      print "Fizz"
    else if i % 5 == 0 then
      print "Buzz"
    else
      print i

    if i == n then 
      () 
    else 
      recur (i + 1)

fizzbuzz_loop 30

Fails with:

⮞ env RUST_BACKTRACE=1 ante fizzbuzz.an
thread 'main' panicked at src/hir/monomorphisation.rs:826:17:
internal error: entered unreachable code: Cannot monomorphise from a TraitDefinition.
No cached impl for '%' 39: (I32 - I32 -> I32 can 600)
stack backtrace:
   0: rust_begin_unwind
   1: core::panicking::panic_fmt
   2: ante::hir::monomorphisation::Context::monomorphise_definition_id
   3: ante::hir::monomorphisation::Context::monomorphise
   4: ante::hir::monomorphisation::Context::monomorphise_call
   5: ante::hir::monomorphisation::Context::monomorphise_call
   6: ante::hir::monomorphisation::Context::monomorphise
   7: ante::hir::monomorphisation::Context::monomorphise
   8: ante::hir::monomorphisation::Context::monomorphise
   9: ante::hir::monomorphisation::Context::monomorphise
  10: ante::hir::monomorphisation::Context::monomorphise_definition_id
  11: ante::hir::monomorphisation::Context::monomorphise
  12: ante::hir::monomorphisation::Context::monomorphise_call
  13: ante::hir::monomorphisation::Context::monomorphise
  14: ante::hir::monomorphisation::Context::monomorphise
  15: ante::hir::monomorphisation::Context::monomorphise
  16: ante::hir::monomorphisation::Context::monomorphise_definition_id
  17: ante::hir::monomorphisation::Context::monomorphise
  18: ante::hir::monomorphisation::Context::monomorphise_call
  19: ante::hir::monomorphisation::Context::monomorphise
  20: ante::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
fish: Job 1, 'env RUST_BACKTRACE=1 ante fizzb…' terminated by signal SIGABRT (Abort)

[jfecher]

Looks like it failed to find the monomorphized trait impl. Odd, I'd think you'd need a more complex example to trigger this bug. Thanks for the issue, I'll take a look.

[jfecher]

Also - in case you or anyone else reading is looking for a workaround using explicit, non-polymorphic types for fizzbuzz_loop will fix the bug:

fizzbuzz_loop (n: U32) = 
  loop (i = 1) ->
    if i % 3 == 0 and i % 5 == 0 then
      print "FizzBuzz"
    else if i % 3 == 0 then
      print "Fizz"
    else if i % 5 == 0 then
      print "Buzz"
    else
      print i

    if i != n then
      recur (i + 1)

fizzbuzz_loop 30

[sullyj3]

Nice, thank you. (And for the implicit tip about if)