Add an option '-C|--copies' to hg status to show the source of copied files.
Copied files are displayed in the form:
A newname
oldname
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b