add internal test making sure dict labels dont stack

Author: zth

jscomp/test/DictInternalRepresentation.js

@@ -0,0 +1,26 @@
+// Make sure labels matched don't "stick" on the builtin dict type
+let stringDict = dict{
+  "first": "hello",
+}
+
+let intDict = dict{
+  "first": 1,
+}
+
+let foo = () => {
+  let first = switch stringDict {
+  | @res.dictPattern {first} => first ++ "2"
+  | _ => "hello"
+  }
+  Js.log(first)
+  let second = switch intDict {
+  | @res.dictPattern {first} => first + 2
+  | _ => 1
+  }
+  Js.log(second)
+  let third = switch stringDict {
+  | @res.dictPattern {first} => first ++ "2"
+  | _ => "hello"
+  }
+  Js.log(third)
+}