Convert Type from an enum into a class (#1350)

This is similar to the way Opcode is structured, which allows us to hang
member functions off of the enumeration.

The primary motivator for this change is the GC proposal (and the
function-references proposal) where a Type can be parameterized:

     (type $T (struct ...))
     (func
       (local (ref $T)
       ...
     )

In this case the type is ref, with a parameter of the type index. Making
Type a class will make it easier to store this additional information.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/type-checker.cc b/src/type-checker.cc
index 11c36dcd..b6c02be4 100644
--- a/src/type-checker.cc
+++ b/src/type-checker.cc
@@ -30,7 +30,7 @@ std::string TypesToString(const TypeVector& types,
   }
 
   for (size_t i = 0; i < types.size(); ++i) {
-    result += GetTypeName(types[i]);
+    result += types[i].GetName();
     if (i < types.size() - 1) {
       result += ", ";
     }
@@ -169,13 +169,13 @@ static bool IsSubtype(Type sub, Type super) {
   if (super == sub) {
     return true;
   }
-  if (IsRefType(super) != IsRefType(sub)) {
+  if (super.IsRef() != sub.IsRef()) {
     return false;
   }
   if (super == Type::Anyref) {
-    return IsRefType(sub);
+    return sub.IsRef();
   }
-  if (IsNullableRefType(super)) {
+  if (super.IsNullableRef()) {
     return sub == Type::Nullref;
   }
   return false;
@@ -731,7 +731,7 @@ Result TypeChecker::OnSelect(Type expected) {
   result |= PeekType(1, &type1);
   result |= PeekType(2, &type2);
   if (expected == Type::Any) {
-    if (IsRefType(type1) || IsRefType(type2)) {
+    if (type1.IsRef() || type2.IsRef()) {
       result = Result::Error;
     } else {
       result |= CheckType(type1, type2);