[pulse] substitute entire linear expressions

Summary:
This allows further normalisation now that terms contain linear
expressions in normal form.

Reviewed By: skcho

Differential Revision: D23241499

fbshipit-source-id: f8e4e759c

infer/src/pulse/PulseFormula.ml

@@ -1069,11 +1069,11 @@ end = struct
     let normalize_term phi t =
       Term.map_variables t ~f:(fun v ->
           let v_canon = (VarUF.find phi.var_eqs v :> Var.t) in
-          let q_opt =
-            let open Option.Monad_infix in
-            Var.Map.find_opt v_canon phi.linear_eqs >>= LinArith.get_as_const
-          in
-          match q_opt with None -> VarSubst v_canon | Some q -> QSubst q )
+          match Var.Map.find_opt v_canon phi.linear_eqs with
+          | None ->
+              VarSubst v_canon
+          | Some l -> (
+            match LinArith.get_as_const l with None -> LinSubst l | Some q -> QSubst q ) )
     in
     let atom' = Atom.map_terms atom ~f:(fun t -> normalize_term phi t) in
     Atom.eval atom' |> sat_of_eval_result

infer/src/pulse/unit/PulseFormulaTest.ml

@@ -168,7 +168,7 @@ let%test_module "normalization" =
 
     let%expect_test _ =
       normalize (x + y < x + y) ;
-      [%expect {|true (no var=var) && v6 = x + y ∧ v7 = x + y && {[v6 + -v7] < 0}|}]
+      [%expect {|unsat|}]
 
     let%expect_test "nonlinear arithmetic" =
       normalize (z * (x + (v * y) + i 1) / w = i 0) ;
@@ -178,7 +178,7 @@ let%test_module "normalization" =
         &&
         v7 = x + v6 ∧ v8 = x + v6 +1 ∧ v10 = 0
         &&
-        {0 = [v9]÷[w]}∧{[v6] = [v]×[y]}∧{[v9] = [z]×[v8]} |}]
+        {0 = [v9]÷[w]}∧{[v6] = [v]×[y]}∧{[v9] = [z]×[x + v6 +1]} |}]
 
     (* check that this becomes all linear equalities *)
     let%expect_test _ =