diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -233,9 +233,35 @@ def rebase(ui, repo, **opts):
                 assert rebaseset
             else:
                 base = scmutil.revrange(repo, [basef or '.'])
+                if not base:
+                    raise util.Abort(_('empty "base" revision set - '
+                                       "can't compute rebase set"))
                 rebaseset = repo.revs(
                     '(children(ancestor(%ld, %d)) and ::(%ld))::',
                     base, dest, base)
+                if not rebaseset:
+                    if base == [dest.rev()]:
+                        if basef:
+                            ui.status(_('nothing to rebase - %s is both "base"'
+                                        ' and destination\n') % dest)
+                        else:
+                            ui.status(_('nothing to rebase - working directory '
+                                        'parent is also destination\n'))
+                    elif not repo.revs('%ld - ::%d', base, dest):
+                        if basef:
+                            ui.status(_('nothing to rebase - "base" %s is '
+                                        'already an ancestor of destination '
+                                        '%s\n') %
+                                      ('+'.join(str(repo[r]) for r in base),
+                                       dest))
+                        else:
+                            ui.status(_('nothing to rebase - working '
+                                        'directory parent is already an '
+                                        'ancestor of destination %s\n') % dest)
+                    else: # can it happen?
+                        ui.status(_('nothing to rebase from %s to %s\n') %
+                                  ('+'.join(str(repo[r]) for r in base), dest))
+                    return 1
             if rebaseset:
                 root = min(rebaseset)
             else:
diff --git a/tests/test-largefiles.t b/tests/test-largefiles.t
--- a/tests/test-largefiles.t
+++ b/tests/test-largefiles.t
@@ -977,7 +977,7 @@ rebased or not.
   M sub2/large6
   saved backup bundle to $TESTTMP/d/.hg/strip-backup/f574fb32bb45-backup.hg (glob)
   0 largefiles cached
-  nothing to rebase
+  nothing to rebase - working directory parent is also destination
   $ [ -f .hg/largefiles/e166e74c7303192238d60af5a9c4ce9bef0b7928 ]
   $ hg log --template '{rev}:{node|short}  {desc|firstline}\n'
   9:598410d3eb9a  modify normal file largefile in repo d
diff --git a/tests/test-rebase-parameters.t b/tests/test-rebase-parameters.t
--- a/tests/test-rebase-parameters.t
+++ b/tests/test-rebase-parameters.t
@@ -87,14 +87,26 @@ These fail:
   abort: empty "source" revision set - nothing to rebase
   [255]
 
+  $ hg rebase --base '1 & !1'
+  abort: empty "base" revision set - can't compute rebase set
+  [255]
+
   $ hg rebase
-  nothing to rebase
+  nothing to rebase - working directory parent is also destination
+  [1]
+
+  $ hg rebase -b.
+  nothing to rebase - e7ec4e813ba6 is both "base" and destination
   [1]
 
   $ hg up -q 7
 
   $ hg rebase --traceback
-  nothing to rebase
+  nothing to rebase - working directory parent is already an ancestor of destination e7ec4e813ba6
+  [1]
+
+  $ hg rebase -b.
+  nothing to rebase - "base" 02de42196ebe is already an ancestor of destination e7ec4e813ba6
   [1]
 
   $ hg rebase --dest '1 & !1'
@@ -137,7 +149,6 @@ Try to rollback after a rebase (fail):
 
   $ cd ..
 
-
 Rebase with base == '.' => same as no arguments (from 3 onto 8):
 
   $ hg clone -q -u 3 a a2
diff --git a/tests/test-rebase-pull.t b/tests/test-rebase-pull.t
--- a/tests/test-rebase-pull.t
+++ b/tests/test-rebase-pull.t
@@ -84,7 +84,7 @@ Invoke pull --rebase and nothing to reba
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
-  nothing to rebase
+  nothing to rebase - working directory parent is already an ancestor of destination 77ae9631bcca
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   updating bookmark norebase
 
diff --git a/tests/test-rebase-scenario-global.t b/tests/test-rebase-scenario-global.t
--- a/tests/test-rebase-scenario-global.t
+++ b/tests/test-rebase-scenario-global.t
@@ -235,7 +235,7 @@ These will abort gracefully (using --bas
 G onto G - rebase onto same changeset:
 
   $ hg rebase -b 6 -d 6
-  nothing to rebase
+  nothing to rebase - eea13746799a is both "base" and destination
   [1]
 
 G onto F - rebase onto an ancestor:
@@ -247,7 +247,7 @@ G onto F - rebase onto an ancestor:
 F onto G - rebase onto a descendant:
 
   $ hg rebase -b 5 -d 6
-  nothing to rebase
+  nothing to rebase - "base" 24b6387c8c8c is already an ancestor of destination eea13746799a
   [1]
 
 C onto A - rebase onto an ancestor: