Failed to parse warning (SQL query as charlist instead of binary)

[smaximov]

Environment

• Elixir & Erlang/OTP versions (elixir --version):

  Erlang/OTP 23 [erts-11.2.2.4] [source] [64-bit] [smp:12:12] [ds:12:12:10] [async-threads:1] [hipe]
  
  Elixir 1.11.4 (compiled with Erlang/OTP 23)
  

• Which version of Dialyxir are you using? (cat mix.lock | grep dialyxir): 1.1.0

Current behavior

Consider this module (requires ecto/ecto_sql/postgrex to compile):

defmodule Repo do
  use Ecto.Repo,
    otp_app: :myapp,
    adapter: Ecto.Adapters.Postgres

  def fails_to_parse_dialyzer_warning do
    'SELECT do_something($1);' |> Repo.query!([1])
  end

  def parses_dialyzer_warning do
    'SELECT $1;' |> Repo.query!([1])
  end
end

The issue with this code is that SQL queries are passed as charlists, but Repo.query/2 expects a binary.

Running mix dialyzer yields:

lib/repo.ex:6:no_return
Function fails_to_parse_dialyzer_warning/0 has no local return.
________________________________________________________________________________
Please file a bug in https://github.com/jeremyjh/dialyxir/issues with this message.
Failed to parse warning:
[{:"(", 1}, {:atom_part, 1, '"'}, {:atom_part, 1, 'S'}, {:atom_part, 1, 'E'}, {:atom_part, 1, 'L'}, {:atom_part, 1, 'E'}, {:atom_part, 1, 'C'}, {:atom_part, 1, 'T'}, {:atom_part, 1, 'd'}, {:atom_part, 1, 'o'}, {:_, 1}, {:atom_part, 1, 's'}, {:atom_part, 1, 'o'}, {:atom_part, 1, 'm'}, {:atom_part,
1, 'e'}, {:atom_part, 1, 't'}, {:atom_part, 1, 'h'}, {:atom_part, 1, 'i'}, {:atom_part, 1, 'n'}, {:atom_part, 1, 'g'}, {:"(", 1}, {:atom_part, 1, '$'}, {:int, 1, 1}, {:")", 1}, {:atom_part, 1, ';'}, {:atom_part, 1, '"'}, {:",", 1}, {:"[", 1}, {:int, 1, 1}, {:"]", 1}, {:")", 1}]


Legacy warning:
lib/repo.ex:7: The call 'Elixir.Repo':'query!'("SELECT do_something($1);",[1]) will never return since it differs in the 1st argument from the success typing arguments: (binary(),[any()])
________________________________________________________________________________
lib/repo.ex:10:no_return
Function parses_dialyzer_warning/0 has no local return.
________________________________________________________________________________
lib/repo.ex:11:call
The function call will not succeed.

Repo.query!(:"\"SELECT$1;\"", [1])

will never return since the 1st arguments differ
from the success typing arguments:

(binary(), [any()])

There're two (maybe unrelated) problems with the result:

1. In the warning emitted for parses_dialyzer_warning/0, the SQL query (a charlist) is formatted as an atom :"\"SELECT$1;\" (also note that the space between SELECT and $1 is missing).
2. Dialyxir fails to parse the warning emitted for fails_to_parse_dialyzer_warning/0, but the only difference between the two functions are SQL queries they are using: one uses SELECT $1, the other — SELECT do_something_with($1).

Expected behavior

It gives two warnings similar to the warning emitted for parses_dialyzer_warning/0 (but with SQL queries formatted correctly as charlists).

Alternative outputs

--format dialyzer:

lib/repo.ex:6: Function fails_to_parse_dialyzer_warning/0 has no local return
lib/repo.ex:7: The call 'Elixir.Repo':'query!'("SELECT do_something($1);",[1]) will never return since it differs in the 1st argument from the success typing arguments: (binary(),[any()])
lib/repo.ex:10: Function parses_dialyzer_warning/0 has no local return
lib/repo.ex:11: The call 'Elixir.Repo':'query!'("SELECT $1;",[1]) will never return since it differs in the 1st argument from the success typing arguments: (binary(),[any()])

Note that SQL queries are displayed correctly as charlists (using Erlang syntax).

--format raw:

{:warn_return_no_exit, {'lib/repo.ex', 6}, {:no_return, [:only_normal, :fails_to_parse_dialyzer_warning, 0]}}
{:warn_failing_call, {'lib/repo.ex', 7}, {:call, [Repo, :query!, '("SELECT do_something($1);",[1])', [1], :only_sig, '(binary(),[any()])', '\#{\'num_rows\':=non_neg_integer(), \'rows\':=\'nil\' | [binary() | [any()]], atom()=>_}', {false, :none}]}}
{:warn_return_no_exit, {'lib/repo.ex', 10}, {:no_return, [:only_normal, :parses_dialyzer_warning, 0]}}
{:warn_failing_call, {'lib/repo.ex', 11}, {:call, [Repo, :query!, '("SELECT $1;",[1])', [1], :only_sig, '(binary(),[any()])', '\#{\'num_rows\':=non_neg_integer(), \'rows\':=\'nil\' | [binary() | [any()]], atom()=>_}', {false, :none}]}}