without this patch:
see https://bugs.gentoo.org/757897
with this patch:
# equery m glib
!!! Ambiguous package name. Choose from:
  dev-haskell/glib
  dev-libs/glib
# equery m git
!!! Ambiguous package name. Choose from:
  dev-haskell/git
  acct-group/git
  dev-vcs/git
  acct-user/git
  dev-ruby/git
# equery m git
!!! Ambiguous package name. Choose from:
  dev-vcs/git
  acct-group/git
  acct-user/git
  dev-ruby/git
  dev-haskell/git


Index: /var/tmp/portage/sys-apps/portage-3.0.11-r1/work/portage-3.0.11/lib/portage/dbapi/cpv_expand.py
===================================================================
--- .orig/lib/portage/dbapi/cpv_expand.py
+++ mod/lib/portage/dbapi/cpv_expand.py
@@ -67,22 +67,23 @@ def cpv_expand(mycpv, mydb=None, use_cac
 				if mydb.cp_list(x+"/"+myp,use_cache=use_cache):
 					matches.append(x+"/"+myp)
 		if len(matches) > 1:
-			virtual_name_collision = False
-			if len(matches) > 1:
-				for x in matches:
-					if not x.startswith(("acct-group/", "acct-user/", "virtual/")):
-						# Assume that the non-virtual is desired.  This helps
-						# avoid the ValueError for invalid deps that come from
-						# installed packages (during reverse blocker detection,
-						# for example).
-						mykey = x
-					else:
-						virtual_name_collision = True
-			if not virtual_name_collision:
-				# AmbiguousPackageName inherits from ValueError,
-				# for backward compatibility with calling code
-				# that already handles ValueError.
-				raise AmbiguousPackageName(matches)
+			#more than 1 match!
+			assert None == mykey
+			for x in matches:
+				if not x.startswith(("acct-group/", "acct-user/", "virtual/")):
+					# Assume that the non-virtual is desired.  This helps
+					# avoid the ValueError for invalid deps that come from
+					# installed packages (during reverse blocker detection,
+					# for example).
+					if None != mykey:
+						#if more than 1 non-virtuals then collision!
+						#eg. try 'equery m git'
+						#
+						# AmbiguousPackageName inherits from ValueError,
+						# for backward compatibility with calling code
+						# that already handles ValueError.
+						raise AmbiguousPackageName(matches)
+					mykey = x
 		elif matches:
 			mykey=matches[0]