Add a typeName() method to each type for error printing purposes.

Test: compiles with mma
Change-Id: I1283c395440282fde1106ad47aa185bdeda75880
diff --git a/VectorType.cpp b/VectorType.cpp
index 1443697..5854f54 100644
--- a/VectorType.cpp
+++ b/VectorType.cpp
@@ -26,6 +26,14 @@
 VectorType::VectorType() {
 }
 
+std::string VectorType::typeName() const {
+    return "vector" + (mElementType == nullptr ? "" : (" of " + mElementType->typeName()));
+}
+
+bool VectorType::isCompatibleElementType(Type *) const {
+    return true;
+}
+
 void VectorType::addNamedTypesToSet(std::set<const FQName> &set) const {
     mElementType->addNamedTypesToSet(set);
 }