diff --git a/mercurial/match.py b/mercurial/match.py
--- a/mercurial/match.py
+++ b/mercurial/match.py
@@ -62,7 +62,10 @@ class match(object):
             pats = _normalize(exclude, 'glob', root, cwd, auditor)
             self.excludepat, em = _buildmatch(ctx, pats, '(?:/|$)')
         if exact:
-            self._files = patterns
+            if isinstance(patterns, list):
+                self._files = patterns
+            else:
+                self._files = list(patterns)
             pm = self.exact
         elif patterns:
             pats = _normalize(patterns, default, root, cwd, auditor)
diff --git a/mercurial/scmutil.py b/mercurial/scmutil.py
--- a/mercurial/scmutil.py
+++ b/mercurial/scmutil.py
@@ -525,9 +525,11 @@ def revpair(repo, revs):
     l = revrange(repo, revs)
 
     if len(l) == 0:
+        if revs:
+            raise util.Abort(_('empty revision range'))
         return repo.dirstate.p1(), None
 
-    if len(l) == 1:
+    if len(l) == 1 and len(revs) == 1 and _revrangesep not in revs[0]:
         return repo.lookup(l[0]), None
 
     return repo.lookup(l[0]), repo.lookup(l[-1])
diff --git a/tests/test-diff-change.t b/tests/test-diff-change.t
--- a/tests/test-diff-change.t
+++ b/tests/test-diff-change.t
@@ -29,6 +29,12 @@ Testing diff --change
   -first
   +second
 
+Test dumb revspecs (issue3474)
+
+  $ hg diff -r 2:2
+  $ hg diff -r "2 and 1"
+  abort: empty revision range
+  [255]
 
 Testing diff --change when merge: