ERL-228: Defining type as a tuple containing a fun() followed by expression throws Emacs error

[OTP-Maintainer]

Original reporter: fenollp
Affected version: OTP-19.0.2
Component: tools
Migrated from: https://bugs.erlang.org/browse/ERL-228

---

Example code (erlang-indent-current-buffer):

{code:erlang}
-type b() :: {fun()}.
a(V) ->
    V.
{code}

{code:erlang}
-module(amqp_leader_proc).

-type routine() :: {fun((any()) -> any()), any()}.
-type routines() :: [].
{code}

Emacs error thrown:
Unbalanced parenthesis

Note: if no expression follows the first type definition no error is thrown.
Note: once the error is thrown indentation halts thus the rest of the file is not checked.

Minified test cases: https://github.com/fenollp/erlang-formatter/pull/8/files
Formatting code used: https://github.com/fenollp/erlang-formatter/blob/issue4/fmt.el

[OTP-Maintainer]

mc_ said:

Looking at the (car (car stack)) in a sample I have, the value is 'fun. Adding before the (t (error "Unbalanced parenthesis")):

((eq (car (car stack)) 'fun)
(erlang-pop stack)
)
(t
(error "Unbalanced parenthesis"))

Resolved the parsing issue and the region was properly indented.

I haven't made the change outside of my local setup to see if it has broader implications; just a "this worked for me" datapoint.

[dgud]

Can not reproduce