Keep both checks in x !== true && x !== false

changes/untagged-bool-literal-checks.fix.md

@@ -0,0 +1 @@
+- Fix untagged variant matches involving boolean literals that skipped the checks for the other cases.

compiler/core/js_exp_make.ml

@@ -910,18 +910,6 @@ let rec simplify_and_ ~n (e1 : t) (e2 : t) : t option =
           | None -> None
           | Some e -> simplify_and_force ~n:(n + 1) e e2)
         | Some a_, Some b_ -> simplify_or_force ~n:(n + 1) a_ b_)
-      | ( Bin
-            ( ((EqEqEq | NotEqEq) as op1),
-              {expression_desc = Var i1},
-              {expression_desc = Bool b1} ),
-          Bin
-            ( ((EqEqEq | NotEqEq) as op2),
-              {expression_desc = Var i2},
-              {expression_desc = Bool b2} ) )
-        when Js_op_util.same_vident i1 i2 ->
-        let op_eq = op1 = op2 in
-        let consistent = if op_eq then b1 = b2 else b1 <> b2 in
-        if consistent then Some e1 else Some false_
       | ( Bin
             ( EqEqEq,
               {expression_desc = Typeof {expression_desc = Var ia}},

tests/tests/src/untagged_bool_literals_test.mjs

@@ -0,0 +1,60 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
+
+import * as Mocha from "mocha";
+import * as Test_utils from "./test_utils.mjs";
+
+function id(x) {
+  return x;
+}
+
+function bothKind(v) {
+  if (v === true || v === false || !(v instanceof Date)) {
+    return "other";
+  } else {
+    return "date";
+  }
+}
+
+function literalKind(v) {
+  if (v === true || v === false) {
+    return "literal";
+  } else {
+    return "other";
+  }
+}
+
+function falseKind(v) {
+  if (v !== false) {
+    return "other";
+  } else {
+    return "false";
+  }
+}
+
+Mocha.describe("Untagged_bool_literals_test", () => {
+  Mocha.test("no case names a boolean literal", () => {
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 32, characters 7-14", bothKind(id(new Date())), "date");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 33, characters 7-14", bothKind(id(/a/)), "other");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 34, characters 7-14", bothKind(id(true)), "other");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 35, characters 7-14", bothKind(id(false)), "other");
+  });
+  Mocha.test("both boolean literals in one case", () => {
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 39, characters 7-14", literalKind(id(true)), "literal");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 40, characters 7-14", literalKind(id(false)), "literal");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 41, characters 7-14", literalKind(id(new Date())), "other");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 42, characters 7-14", literalKind(id(/a/)), "other");
+  });
+  Mocha.test("bool payload beside @as(true)", () => {
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 46, characters 7-14", falseKind(id(false)), "false");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 47, characters 7-14", falseKind(id("hello")), "other");
+    Test_utils.eq("File \"untagged_bool_literals_test.res\", line 48, characters 7-14", falseKind(id(true)), "other");
+  });
+});
+
+export {
+  id,
+  bothKind,
+  literalKind,
+  falseKind,
+}
+/*  Not a pure module */

tests/tests/src/untagged_bool_literals_test.res

@@ -0,0 +1,50 @@
+open Mocha
+open Test_utils
+
+// Checks against both boolean literals must not assume that the value is a
+// boolean: in an untagged variant it can be any of the payloads (#9098)
+
+@unboxed type withBoth = D(Date.t) | @as(true) Lt | @as(false) Lf | R(RegExp.t)
+@unboxed type withTrue = Bo(bool) | S(string) | @as(true) LitTrue
+
+@inline(never) let id = x => x
+
+let bothKind = (v: withBoth) =>
+  switch v {
+  | D(_) => "date"
+  | _ => "other"
+  }
+
+let literalKind = (v: withBoth) =>
+  switch v {
+  | Lt | Lf => "literal"
+  | _ => "other"
+  }
+
+let falseKind = (v: withTrue) =>
+  switch v {
+  | Bo(false) => "false"
+  | _ => "other"
+  }
+
+describe(__MODULE__, () => {
+  test("no case names a boolean literal", () => {
+    eq(__LOC__, bothKind(id(D(Date.make()))), "date")
+    eq(__LOC__, bothKind(id(R(/a/))), "other")
+    eq(__LOC__, bothKind(id(Lt)), "other")
+    eq(__LOC__, bothKind(id(Lf)), "other")
+  })
+
+  test("both boolean literals in one case", () => {
+    eq(__LOC__, literalKind(id(Lt)), "literal")
+    eq(__LOC__, literalKind(id(Lf)), "literal")
+    eq(__LOC__, literalKind(id(D(Date.make()))), "other")
+    eq(__LOC__, literalKind(id(R(/a/))), "other")
+  })
+
+  test("bool payload beside @as(true)", () => {
+    eq(__LOC__, falseKind(id(Bo(false))), "false")
+    eq(__LOC__, falseKind(id(S("hello"))), "other")
+    eq(__LOC__, falseKind(id(LitTrue)), "other")
+  })
+})