Restrict allowed operators when converting exprs to guards

Summary: Conversion of expressions to guards is only possible for certain allowed operators (for example, `++` is not accepted in a guard expression).

Reviewed By: RobinMorisset

Differential Revision: D41377868

fbshipit-source-id: 02efee2e02a23fe68c546786716ffe85eaede2b0

Author: VLanvin

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/ast/Filters.scala

@@ -28,6 +28,37 @@ object Filters {
       "is_tuple",
     )
 
+  val guards_binop: Set[String] =
+    Set(
+      "/",
+      "*",
+      "-",
+      "+",
+      "div",
+      "rem",
+      "band",
+      "bor",
+      "bxor",
+      "bsl",
+      "bsr",
+      "or",
+      "xor",
+      "and",
+      ">=",
+      ">",
+      "=<",
+      "<",
+      "/=",
+      "=/=",
+      "==",
+      "=:=",
+      "andalso",
+      "orelse",
+    )
+
+  val guards_unop: Set[String] =
+    Set("bnot", "+", "-", "not")
+
   private def isPredicateFun(name: String, arity: Int): Boolean =
     (name, arity) match {
       case (_, 1) =>
@@ -54,11 +85,11 @@ object Filters {
         for {
           argsT <- asTests(args)
         } yield TestCall(Id(f, arity), argsT)(expr.pos)
-      case UnOp(op, arg) =>
+      case UnOp(op, arg) if guards_unop(op) =>
         for {
           argT <- asTest(arg)
         } yield TestUnOp(op, argT)(expr.pos)
-      case BinOp(op, arg1, arg2) =>
+      case BinOp(op, arg1, arg2) if guards_binop(op) =>
         for {
           arg1T <- asTest(arg1)
           arg2T <- asTest(arg2)

eqwalizer/test_projects/_cli/checkable_funs.cli

@@ -1,10 +1,10 @@
 all funs:
-                                               All : 2773
-                                         Checkable : 2512
+                                               All : 2774
+                                         Checkable : 2513
                               Well-typed checkable : 1615
                                    Checkable ratio : 91%
                          Health ratio of checkable : 64%
-                                       error count : 896
+                                       error count : 897
 
 --------------------------------------------
 generated funs:
@@ -26,19 +26,19 @@ generated non-test funs:
 
 --------------------------------------------
 non-generated funs:
-                                               All : 2773
-                                         Checkable : 2512
+                                               All : 2774
+                                         Checkable : 2513
                               Well-typed checkable : 1615
                                    Checkable ratio : 91%
                          Health ratio of checkable : 64%
-                                       error count : 896
+                                       error count : 897
 
 --------------------------------------------
 non-generated non-test funs (most important):
-                                               All : 2771
-                                         Checkable : 2510
+                                               All : 2772
+                                         Checkable : 2511
                               Well-typed checkable : 1614
                                    Checkable ratio : 91%
                          Health ratio of checkable : 64%
-                                       error count : 895
+                                       error count : 896
 

eqwalizer/test_projects/_cli/discarded_specs.cli

@@ -49,5 +49,5 @@ type_aliases:uses_trans_unbound_var/2
 type_aliases:uses_ty_w_unbound_var/2
 type_aliases:uses_ty_w_unbound_var2/0
 Discarded specs: 49
-Total specs: 2650
-Discarded ratio: 1.8491 %
+Total specs: 2651
+Discarded ratio: 1.8484 %

eqwalizer/test_projects/_cli/long_errors.cli

@@ -1,3 +1,3 @@
-Average error message length: 22.09649 characters
+Average error message length: 22.086357 characters
 Longest error message: 122 characters
 Average error message length for the longest 10% of error msgs: 46.886074 characters

eqwalizer/test_projects/_cli/misc.json

@@ -2562,7 +2562,8 @@
           "use_invalid_opaque_2/1",
           "f/1",
           "g/1",
-          "fuzz01/0"
+          "fuzz01/0",
+          "fuzz02/0"
         ]
       },
       {

eqwalizer/test_projects/check_gradual/src/gradual_misc.erl

@@ -32,3 +32,7 @@ g(#{(a #{ b => c }) := _})  ->
 -spec fuzz01() -> ok.
 fuzz01() when #{(true andalso false) => {}} ->
     ok.
+
+-spec fuzz02() -> ok.
+fuzz02() ->
+    <<X || X <- [], (X ++ X) >>.

eqwalizer/test_projects/check_gradual/src/gradual_misc.erl.check

@@ -34,3 +34,9 @@ g(#{(a #{ b => c }) := _})  ->             | OK      |
 -spec fuzz01() -> ok.                      |         |
 fuzz01() when #{(true andalso false) => {}…… OK      |
     ok.                                    |         |
+                                           |         |
+-spec fuzz02() -> ok.                      |         |
+fuzz02() ->                                | ERROR   |
+    <<X || X <- [], (X ++ X) >>.           |         | << || >>.
+                                           |         | Expected: 'ok'
+                                           |         | Got     : binary()