[infer][test_build] add fatal warning and fix instance

Reviewed By: jvillard

Differential Revision: D15536635

fbshipit-source-id: b034a9788

infer/src/base/ProcessPool.ml

@@ -151,7 +151,7 @@ let has_dead_child pool =
          , status ) )
 
 
-let child_is_idle = function Idle _ -> true | _ -> false
+let child_is_idle = function Idle -> true | _ -> false
 
 let all_children_idle pool = Array.for_all pool.children_states ~f:child_is_idle
 

infer/src/dune.common.in

@@ -40,7 +40,7 @@ let common_cflags =
    * fixed one day.
    *)
   let fatal_warnings =
-    "+3+5+6+8+10+11+12+14+18+19+20+21+23+26+29+27+32+33+34+35+37+38+39+50+52+57+60"
+    "+3+5+6+8+10+11+12+14+18+19+20+21+23+26+29+27+28+32+33+34+35+37+38+39+50+52+57+60"
   in
   let warnings = fatal_warnings ^ "-4-9-40-41-42-45-48" in
   let common_flags =