Compiler warning indicating probably incorrect code

[build] /Users/rchapman/HPCC-Platform/system/xmllib/libxml_xpathprocessor.cpp:970:21: warning: logical not is only applied to the left hand side of this comparison [-Wlogical-not-parentheses]
[build]         if (!obj || !obj->type==XPATH_NODESET || !obj->nodesetval || !obj->nodesetval->nodeTab || obj->nodesetval->nodeNr<1)

obj->type!=XPATH_NODESET