This blog is updated daily.
A general description is here.
‘R CMD check’ does more thorough checking of declared packages and namespaces. It reports
• packages declared in more than one of the ‘Depends’, ‘Imports’, ‘Suggests’ and ‘Enhances’ fields of the ‘DESCRIPTION’ file.
• namespaces declared in ‘Imports’ but not imported from, neither in the ‘NAMESPACE’ file nor using the ‘::’ nor ‘:::’ operators.
• packages which are used in ‘library()’ or ‘requires()’ calls in the R code but were already put on the search path _via_ ‘Depends’.
• packages declared in ‘Depends’ not imported _via_ the ‘NAMESPACE’ file (except the standard packages). Objects used from ‘Depends’ packages should be imported to avoid conflicts.
See ‘Writing R Extensions’ for good practice.