LibJS: Improve Reference::get() TypeError message for nullish base

"ToObject on null or undefined" is useless.
"Cannot get property 'foo' of undefined" isn't.

Userland/Libraries/LibJS/Runtime/ErrorTypes.h

@@ -148,8 +148,9 @@
                                         "target is non-extensible")                                                                     \
     M(ProxyTwoArguments, "Proxy constructor requires at least two arguments")                                                           \
     M(ReduceNoInitial, "Reduce of empty array with no initial value")                                                                   \
-    M(ReferenceNullishAssignment, "Cannot set property '{}' of {}")                                                                     \
-    M(ReferencePrimitiveAssignment, "Cannot set property '{}' of {} '{}'")                                                              \
+    M(ReferenceNullishGetProperty, "Cannot get property '{}' of {}")                                                                    \
+    M(ReferenceNullishSetProperty, "Cannot set property '{}' of {}")                                                                    \
+    M(ReferencePrimitiveSetProperty, "Cannot set property '{}' of {} '{}'")                                                             \
     M(ReferenceUnresolvable, "Unresolvable reference")                                                                                  \
     M(ReflectArgumentMustBeAFunction, "First argument of Reflect.{}() must be a function")                                              \
     M(ReflectArgumentMustBeAnObject, "First argument of Reflect.{}() must be an object")                                                \

Userland/Libraries/LibJS/Runtime/Reference.cpp

@@ -51,15 +51,15 @@ void Reference::put(GlobalObject& global_object, Value value)
 
     if (!base.is_object() && vm.in_strict_mode()) {
         if (base.is_nullish())
-            vm.throw_exception<TypeError>(global_object, ErrorType::ReferenceNullishAssignment, m_name.to_value(global_object.vm()).to_string_without_side_effects(), base.to_string_without_side_effects());
+            vm.throw_exception<TypeError>(global_object, ErrorType::ReferenceNullishSetProperty, m_name.to_value(vm).to_string_without_side_effects(), base.to_string_without_side_effects());
         else
-            vm.throw_exception<TypeError>(global_object, ErrorType::ReferencePrimitiveAssignment, m_name.to_value(global_object.vm()).to_string_without_side_effects(), base.typeof(), base.to_string_without_side_effects());
+            vm.throw_exception<TypeError>(global_object, ErrorType::ReferencePrimitiveSetProperty, m_name.to_value(vm).to_string_without_side_effects(), base.typeof(), base.to_string_without_side_effects());
         return;
     }
 
     if (base.is_nullish()) {
         // This will always fail the to_object() call below, let's throw the TypeError ourselves with a nice message instead.
-        vm.throw_exception<TypeError>(global_object, ErrorType::ReferenceNullishAssignment, m_name.to_value(global_object.vm()).to_string_without_side_effects(), base.to_string_without_side_effects());
+        vm.throw_exception<TypeError>(global_object, ErrorType::ReferenceNullishSetProperty, m_name.to_value(vm).to_string_without_side_effects(), base.to_string_without_side_effects());
         return;
     }
 
@@ -103,7 +103,15 @@ Value Reference::get(GlobalObject& global_object)
         return value;
     }
 
-    auto* object = base().to_object(global_object);
+    auto base = this->base();
+
+    if (base.is_nullish()) {
+        // This will always fail the to_object() call below, let's throw the TypeError ourselves with a nice message instead.
+        vm.throw_exception<TypeError>(global_object, ErrorType::ReferenceNullishGetProperty, m_name.to_value(vm).to_string_without_side_effects(), base.to_string_without_side_effects());
+        return {};
+    }
+
+    auto* object = base.to_object(global_object);
     if (!object)
         return {};