Rework how overriden otp types are compiled and loaded

.travis.yml

@@ -21,7 +21,7 @@ matrix:
   # At that point, update otp_release in the corresponding list below
 
   - env: TEST=".travis/travis_has_latest_otp_version"
-    otp_release: 21.2
+    otp_release: 22.1
 
   # Run make target specialized for the checks we want to make in Travis for
   # the latest OTP release.
@@ -36,9 +36,9 @@ matrix:
 # The latest OTP version is special and therefore explicitly
 # included above instead.
 otp_release:
-
-  - 21.0
+  - 22.0
   # Last minor version of older OTP releases
+  - 21.3
   - 20.3
   - 19.3
 

src/gradualizer_db.erl

@@ -126,8 +126,6 @@ import_module(Module) ->
 
 -type opts() :: #{autoimport => boolean()}.
 -define(default_opts, #{autoimport => true}).
--define(prelude_erl, filename:join(code:priv_dir(gradualizer),
-                                   "otp_spec_fix.erl")).
 
 -record(state, {specs   = #{} :: #{mfa() => [type()]},
                 types   = #{} :: #{mfa() => #typeinfo{}},
@@ -256,19 +254,8 @@ code_change(_OldVsn, State, _Extra) ->
 
 -spec import_prelude(state()) -> state().
 import_prelude(State) ->
-    %% Read the beam from file system or from escript archive
-    case code:which(gradualizer_prelude) of
-        cover_compiled ->
-            %% Cover messes with the code server. Hopefully we're not
-            %% using cover when running as an escript.
-            ErlFile = filename:join(filename:dirname(?FILE),
-                                    "gradualizer_prelude.erl"),
-            import_erl_files([ErlFile], State);
-        Filename when is_list(Filename) ->
-            {ok, BeamCode, _Filename} = erl_prim_loader:get_file(Filename),
-            {ok, State1 = #state{}} = import_beam_files([BeamCode], State),
-            State1
-    end.
+    Forms = gradualizer_prelude:get_prelude(),
+    _NewState1 = import_absform(gradualizer_prelude, Forms, State).
 
 %% @doc ensure DB server is started
 call(Request) ->

src/gradualizer_prelude.erl

@@ -1,5 +1,7 @@
 -module(gradualizer_prelude).
 
+-compile({parse_transform, gradualizer_prelude_parse_trans}).
+
 %% This module contains specs to replace incorrect or inexact specs in OTP.
 
 -spec erlang:apply(function(), [any()]) -> any().

src/gradualizer_prelude_parse_trans.erl

@@ -0,0 +1,15 @@
+-module(gradualizer_prelude_parse_trans).
+
+-export([parse_transform/2]).
+
+parse_transform(Forms, _Options) ->
+    [{attribute, _, file, _} = File,
+     {attribute, _, module, _} = Mod
+     |SpecForms] = Forms,
+
+    [File,
+     Mod,
+     {attribute,2,export,[{get_prelude,0}]},
+     {function,3,get_prelude,0,
+      [{clause,3,[],[],
+        [erl_parse:abstract(SpecForms)]}]}].