diff -r 4da5fa99f904 b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
diff -r 4da5fa99f904 b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
diff -r 4da5fa99f904 a
--- a/a
+++ b/a
@@ -0,0 +1,1 @@
+foo
diff -r 4da5fa99f904 b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+123
abort: Ambiguous identifier!
abort: Ambiguous identifier!