Dialyzer bug in OTP 24.x

epgsql.erl

-module(epgsql).
-export_type([connect_opts/0]).
-type connect_opts() :: foo:bar(). %% unknown type here

epgsql_cmd_connect.erl

-module(epgsql_cmd_connect).
-export([open_socket/1]).

%% ... no code at line 3 ...

-spec open_socket(epgsql:connect_opts()) -> ok.
open_socket(_ConnectOpts) ->
  ok.

output.txt

$ ./run.sh 
+ erlc +debug_info epgsql_cmd_connect.erl epgsql.erl
+ dialyzer epgsql.beam epgsql_cmd_connect.beam --plt /home/jespereskilson/dev/kred/build/otp.plt --no_check_plt
  Proceeding with analysis...
Unknown types:
  foo:bar/0 (epgsql.erl:3:25)
  foo:bar/0 (epgsql_cmd_connect.erl:3:25)
 done in 0m0.57s
done (passed successfully)

run.sh

#!/bin/bash
set -x
erlc +debug_info *.erl
dialyzer *.beam --plt ~/dev/kred/build/otp.plt  --no_check_plt

Dialyzer reports two errors, but the second one is wrong.

  foo:bar/0 (src/epgsql.erl:3:25)
  foo:bar/0 (src/epgsql_cmd_connect.erl:3:25)

The first one is correct, as the type foo:bar() does not exist.

1. The first bug is that second errors is bogus, because the spec -spec open_socket(epgsql:connect_opts()) -> ok. does not refer to an unknown type.
2. The second bug is that the the line and column info for the second bug is definitely wrong; it refers to the location of the first error, but has the filename of the second error.

OTP versions prior to 24 are not affected. All OTP 24.x-25.x versions are affected.

To reproduce this error, use "download zip", unpack it locally, and run the run.sh script.