Add missing refinement of dynamic/0 into dynamic/1

Summary:
Leverage `dynamic/1` to refine `dynamic/0` in occurrence typing. This effectively solves the issue where the types of all parameters are not refined if one of them is `dynamic()`.

The introduction of new `dynamic/1`'s causes an issue with an existing optimization in `subtype` where we checked for the syntactic presence of a type alias before unfolding it (needed for very large aliases). Fix it by adding `BoundedDynamicType` to this check.

Reviewed By: ilya-klyuchnikov

Differential Revision: D68207950

fbshipit-source-id: f9704adb46cc804297df0c6c19c794721af0a7dc

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/tc/Occurrence.scala

@@ -808,6 +808,8 @@ final class Occurrence(pipelineContext: PipelineContext) {
         restrict(body, t2)
       case (BoundedDynamicType(t), s) =>
         BoundedDynamicType(restrict(t, s))
+      case (DynamicType, s) =>
+        BoundedDynamicType(s)
       case (OpaqueType(_, _), _) =>
         t1
       case (_, _) =>

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/tc/Subtype.scala

@@ -70,7 +70,7 @@ class Subtype(pipelineContext: PipelineContext) {
         subTypePol(t1, bound, seen)
       case (RemoteType(rid, args), _) =>
         val body = util.getTypeDeclBody(rid, args)
-        containsType(t1, t2) || subTypePol(body, t2, seen + ((t1, v1) -> (t2, v2)))
+        containsType(t1, t2, v2) || subTypePol(body, t2, seen + ((t1, v1) -> (t2, v2)))
       case (_, RemoteType(rid, args)) =>
         val body = util.getTypeDeclBody(rid, args)
         subTypePol(t1, body, seen + ((t1, v1) -> (t2, v2)))
@@ -259,12 +259,14 @@ class Subtype(pipelineContext: PipelineContext) {
         false
     })
 
-  private def containsType(t1: Type, t2: Type): Boolean = {
+  private def containsType(t1: Type, t2: Type, v2: Variance): Boolean = {
     t2 match {
       case AnyType       => true
       case _ if t1 == t2 => true
       case UnionType(tys) =>
-        tys.exists(containsType(t1, _))
+        tys.exists(containsType(t1, _, v2))
+      case BoundedDynamicType(bound) if v2 == + =>
+        containsType(t1, bound, v2)
       case _ => false
     }
   }