Relax an assert slightly after the change to unbox keys in-TC

hphp/runtime/vm/translator/hopt/ir.h

@@ -2066,7 +2066,7 @@ struct VectorEffects {
   static bool getStackValue(const IRInstruction* inst, uint32_t index,
                             SSATmp*& value, Type& type);
 
-  VectorEffects(const IRInstruction* inst) {
+  explicit VectorEffects(const IRInstruction* inst) {
     int keyIdx = vectorKeyIdx(inst);
     int valIdx = vectorValIdx(inst);
     init(inst->getOpcode(),
@@ -2074,6 +2074,7 @@ struct VectorEffects {
          keyIdx == -1 ? Type::None : inst->getSrc(keyIdx)->getType(),
          valIdx == -1 ? Type::None : inst->getSrc(valIdx)->getType());
   }
+
   template<typename Container>
   VectorEffects(Opcode opc, const Container& srcs) {
     int keyIdx = vectorKeyIdx(opc);
@@ -2083,14 +2084,17 @@ struct VectorEffects {
          keyIdx == -1 ? Type::None : srcs[keyIdx]->getType(),
          valIdx == -1 ? Type::None : srcs[valIdx]->getType());
   }
+
   VectorEffects(Opcode op, Type base, Type key, Type val) {
     init(op, base, key, val);
   }
+
   VectorEffects(Opcode op, SSATmp* base, SSATmp* key, SSATmp* val) {
     auto typeOrNone =
       [](SSATmp* val){ return val ? val->getType() : Type::None; };
     init(op, typeOrNone(base), typeOrNone(key), typeOrNone(val));
   }
+
   Type baseType;
   Type valType;
   bool baseTypeChanged;

hphp/runtime/vm/translator/hopt/vectortranslator.cpp

@@ -119,7 +119,13 @@ void VectorEffects::init(Opcode op, const Type origBase,
 
   // Canonicalize the op to SetProp or SetElem
   op = canonicalOp(op);
-  assert(key.equals(Type::None) || key.isKnownDataType());
+
+  // We're not expecting types other than specific known data types
+  // (or for keys, Cell).  (At least for keys it might work since the
+  // helpers generally operate on cells, but we're asserting anyway
+  // since this shouldn't actually happen.)
+  assert(key.equals(Type::None) || key.isKnownDataType() ||
+         key.equals(Type::Cell));
   assert(origVal.equals(Type::None) || origVal.isKnownDataType());
 
   if ((op == SetElem || op == SetProp) &&