* cmdline/apt-get.cc:

  - if a package can't be removed as it is not installed, suggest to
    the user an (installed) multiarch silbing with 'Did you mean?'

cmdline/apt-get.cc

@@ -904,7 +904,23 @@ struct TryToRemove {
       if ((Pkg->CurrentVer == 0 && PurgePkgs == false) ||
 	  (PurgePkgs == true && Pkg->CurrentState == pkgCache::State::NotInstalled))
       {
-	 ioprintf(c1out,_("Package %s is not installed, so not removed\n"),Pkg.FullName(true).c_str());
+	 pkgCache::GrpIterator Grp = Pkg.Group();
+	 pkgCache::PkgIterator P = Grp.PackageList();
+	 for (; P.end() != true; P = Grp.NextPkg(P))
+	 {
+	    if (P == Pkg)
+	       continue;
+	    if (P->CurrentVer != 0 || (PurgePkgs == true && P->CurrentState != pkgCache::State::NotInstalled))
+	    {
+	       // TRANSLATORS: Note, this is not an interactive question
+	       ioprintf(c1out,_("Package '%s' is not installed, so not removed. Did you mean '%s'?\n"),
+			Pkg.FullName(true).c_str(), P.FullName(true).c_str());
+	       break;
+	    }
+	 }
+	 if (P.end() == true)
+	    ioprintf(c1out,_("Package '%s' is not installed, so not removed\n"),Pkg.FullName(true).c_str());
+
 	 // MarkInstall refuses to install packages on hold
 	 Pkg->SelectedState = pkgCache::State::Hold;
       }

debian/changelog

@@ -33,6 +33,9 @@ apt (0.8.16~exp13) UNRELEASED; urgency=low
     - use pdiff for Translation-* files if available (Closes: #657902)
   * ftparchive/writer.cc:
     - add 'Translation-*' to the default patterns
+  * cmdline/apt-get.cc:
+    - if a package can't be removed as it is not installed, suggest to
+      the user an (installed) multiarch silbing with 'Did you mean?'
 
   [ Steve Langasek ]
   * cmdline/apt-get.cc:
@@ -55,7 +58,7 @@ apt (0.8.16~exp13) UNRELEASED; urgency=low
   * apt-pkg/contrib/fileutl.h:
     - fix compat with FileFd::OpenDescriptor() in ReadOnlyGzip mode
 
- -- David Kalnischkies <kalnischkies@gmail.com>  Sat, 18 Feb 2012 19:44:16 +0100
+ -- David Kalnischkies <kalnischkies@gmail.com>  Sat, 18 Feb 2012 20:41:32 +0100
 
 apt (0.8.16~exp12) experimental; urgency=low
 

test/integration/test-suggest-installed-multiarch-silbing

@@ -0,0 +1,66 @@
+#!/bin/sh
+set -e
+
+TESTDIR=$(readlink -f $(dirname $0))
+. $TESTDIR/framework
+setupenvironment
+configarchitecture 'amd64' 'i386' 'armel'
+
+insertinstalledpackage 'foo' 'i386' '1'
+insertpackage 'unstable' 'foo' 'amd64,i386' '1'
+
+insertinstalledpackage 'foo2' 'i386' '1'
+insertpackage 'unstable' 'foo2' 'i386' '1'
+
+insertinstalledpackage 'foo3' 'amd64' '1'
+insertpackage 'unstable' 'foo3' 'amd64,i386' '1'
+
+insertinstalledpackage 'samefoo' 'i386,amd64' '1' 'Multi-Arch: same'
+insertpackage 'unstable' 'samefoo' 'amd64,i386,armel' '1' 'Multi-Arch: same'
+
+insertinstalledpackage 'samefoo2' 'i386' '1' 'Multi-Arch: same'
+insertpackage 'unstable' 'samefoo2' 'amd64,i386,armel' '1' 'Multi-Arch: same'
+
+setupaptarchive
+
+testequal "Reading package lists...
+Building dependency tree...
+Package 'foo' is not installed, so not removed. Did you mean 'foo:i386'?
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." aptget remove foo -s
+
+testequal "Reading package lists...
+Building dependency tree...
+The following packages will be REMOVED:
+  foo2:i386
+0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
+Remv foo2:i386 [1]" aptget remove foo2 -s
+
+testequal "Reading package lists...
+Building dependency tree...
+The following packages will be REMOVED:
+  foo3
+0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
+Remv foo3 [1]" aptget remove foo3 -s
+
+testequal "Reading package lists...
+Building dependency tree...
+Package 'foo3:i386' is not installed, so not removed. Did you mean 'foo3'?
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." aptget remove foo3:i386 -s
+
+testequalor2 "Reading package lists...
+Building dependency tree...
+Package 'samefoo:armel' is not installed, so not removed. Did you mean 'samefoo'?
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." "Reading package lists...
+Building dependency tree...
+Package 'samefoo:armel' is not installed, so not removed. Did you mean 'samefoo:i386'?
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." aptget remove samefoo:armel -s
+
+testequal "Reading package lists...
+Building dependency tree...
+Package 'samefoo2' is not installed, so not removed. Did you mean 'samefoo2:i386'?
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." aptget remove samefoo2 -s
+
+testequal "Reading package lists...
+Building dependency tree...
+Package 'samefoo2:armel' is not installed, so not removed. Did you mean 'samefoo2:i386'?
+0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded." aptget remove samefoo2:armel -s