Fix like nullable type treatment in the emitter

Summary:
When like type support was implemented, we didn't correctly mark like types as not being "simple" types. This led to nullable  part of the type being swallowed.

This diff fixes that by adding an arm and also gets rid of the catch all arm of the match expression so that this doesn't happen again in the future.

Reviewed By: mdko

Differential Revision: D63980235

fbshipit-source-id: 54b5ab697452a1e761340380a054b93cc93a4e09

hphp/hack/src/hackc/emitter/emit_type_hint.rs

@@ -364,7 +364,14 @@ fn param_hint_to_type_info(
 ) -> Result<TypeInfo> {
     let Hint(_, h) = hint;
     let is_simple_hint = match h.as_ref() {
-        Hsoft(_) | Hoption(_) | Haccess(_, _) | Hfun(_) | Hdynamic | Hnonnull | Hmixed => false,
+        Hlike(_)
+        | Hsoft(_)
+        | Hoption(_)
+        | Haccess(_, _)
+        | Hfun(_)
+        | Hdynamic
+        | Hnonnull
+        | Hmixed => false,
         Happly(Id(_, s), hs) => {
             hs.is_empty()
                 && s != "\\HH\\dynamic"
@@ -373,7 +380,19 @@ fn param_hint_to_type_info(
                 && !tparams.contains(&s.as_str())
         }
         Habstr(s, hs) => hs.is_empty() && !tparams.contains(&s.as_str()),
-        _ => true,
+        Hprim(_)
+        | Htuple(_)
+        | HclassArgs(_)
+        | Hshape(_)
+        | Hrefinement(_, _)
+        | Hwildcard
+        | HvecOrDict(_, _)
+        | Hthis
+        | Hnothing
+        | Hunion(_)
+        | Hintersection(_)
+        | HfunContext(_)
+        | Hvar(_) => true,
     };
     let tc = hint_to_type_constraint(kind, tparams, skipawaitable, hint)?;
     make_type_info(

hphp/test/slow/like_types/like_nullable.php.expect

@@ -0,0 +1 @@
+NULL