Captured function not typechecked

[jfecher]

if true then
    f () = print "hi"
    g () = f ()
    g ()

Fails with

thread 'main' panicked at 'internal error: entered unreachable code', src/types/mod.rs:227:48
stack backtrace:
   0: rust_begin_unwind
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/std/src/panicking.rs:556:5
   1: core::panicking::panic_fmt
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/panicking.rs:142:14
   2: core::panicking::panic
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/panicking.rs:48:5
   3: ante::types::GeneralizedType::into_monotype
             at ./src/types/mod.rs:227:48
   4: ante::hir::monomorphisation::Context::pack_closure_environment::{{closure}}
             at ./src/hir/monomorphisation.rs:1175:27
   5: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &mut F>::call_once
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/ops/function.rs:309:13
   6: core::option::Option<T>::map
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/option.rs:929:29
   7: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::next
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/adapters/map.rs:103:9
   8: <alloc::collections::vec_deque::VecDeque<T,A> as alloc::collections::vec_deque::spec_extend::SpecExtend<T,I>>::spec_extend
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/collections/vec_deque/spec_extend.rs:23:35
   9: <alloc::collections::vec_deque::VecDeque<T,A> as core::iter::traits::collect::Extend<T>>::extend
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/collections/vec_deque/mod.rs:2991:9
  10: <alloc::collections::vec_deque::VecDeque<T> as core::iter::traits::collect::FromIterator<T>>::from_iter
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/collections/vec_deque/mod.rs:2951:9
  11: core::iter::traits::iterator::Iterator::collect
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/traits/iterator.rs:1836:9
  12: ante::hir::monomorphisation::Context::pack_closure_environment
             at ./src/hir/monomorphisation.rs:1172:19
  13: ante::hir::monomorphisation::Context::monomorphise_lambda
             at ./src/hir/monomorphisation.rs:1126:24
  14: ante::hir::monomorphisation::Context::monomorphise
             at ./src/hir/monomorphisation.rs:114:31
  15: ante::hir::monomorphisation::Context::monomorphise_nonlocal_definition
             at ./src/hir/monomorphisation.rs:899:21
  16: ante::hir::monomorphisation::Context::monomorphise_definition_id
             at ./src/hir/monomorphisation.rs:775:27
  17: ante::hir::monomorphisation::Context::monomorphise_variable
             at ./src/hir/monomorphisation.rs:635:26
  18: ante::hir::monomorphisation::Context::monomorphise
             at ./src/hir/monomorphisation.rs:113:35
  19: ante::hir::monomorphisation::Context::monomorphise_call
             at ./src/hir/monomorphisation.rs:1301:32
  20: ante::hir::monomorphisation::Context::monomorphise
             at ./src/hir/monomorphisation.rs:115:35
  21: ante::hir::monomorphisation::Context::monomorphise_sequence::{{closure}}
             at ./src/hir/monomorphisation.rs:1395:65
  22: core::iter::adapters::map::map_fold::{{closure}}
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/adapters/map.rs:84:28
  23: core::iter::traits::iterator::Iterator::fold
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/traits/iterator.rs:2414:21
  24: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/adapters/map.rs:124:9
  25: core::iter::traits::iterator::Iterator::for_each
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/traits/iterator.rs:831:9
  26: <alloc::vec::Vec<T,A> as alloc::vec::spec_extend::SpecExtend<T,I>>::spec_extend
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/vec/spec_extend.rs:40:17
  27: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter_nested::SpecFromIterNested<T,I>>::from_iter
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/vec/spec_from_iter_nested.rs:62:9
  28: <alloc::vec::Vec<T> as alloc::vec::spec_from_iter::SpecFromIter<T,I>>::from_iter
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/vec/spec_from_iter.rs:33:9
  29: <alloc::vec::Vec<T> as core::iter::traits::collect::FromIterator<T>>::from_iter
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/alloc/src/vec/mod.rs:2649:9
  30: core::iter::traits::iterator::Iterator::collect
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/iter/traits/iterator.rs:1836:9
  31: ante::util::fmap
             at ./src/util/mod.rs:16:5
  32: ante::hir::monomorphisation::Context::monomorphise_sequence
             at ./src/hir/monomorphisation.rs:1395:26
  33: ante::hir::monomorphisation::Context::monomorphise
             at ./src/hir/monomorphisation.rs:125:35
  34: ante::hir::monomorphisation::Context::monomorphise_if
             at ./src/hir/monomorphisation.rs:1383:29
  35: ante::hir::monomorphisation::Context::monomorphise
             at ./src/hir/monomorphisation.rs:117:24
  36: ante::hir::monomorphisation::monomorphise
             at ./src/hir/monomorphisation.rs:30:5
  37: ante::compile
             at ./src/main.rs:156:15
  38: ante::main
             at ./src/main.rs:100:9
  39: core::ops::function::FnOnce::call_once
             at /rustc/e7119a0300b87a3d670408ee8e847c6821b3ae80/library/core/src/ops/function.rs:251:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
exit 101