+
+## ------------------- ##
+## %define, --define. ##
+## ------------------- ##
+
+AT_SETUP([%define, --define])
+
+AT_DATA([input.y],
+[[%define var "value1"
+%%
+start: ;
+]])
+
+AT_BISON_CHECK([[input.y -DFOO -DFOO -Dvar=value]], [0], [],
+[[<command line>:4: warning: %define variable `FOO' redefined
+<command line>:3: warning: previous definition
+input.y:1.9-11: warning: %define variable `var' redefined
+<command line>:5: warning: previous definition
+<command line>:3: warning: %define variable `FOO' is not used
+<command line>:4: warning: %define variable `FOO' is not used
+<command line>:5: warning: %define variable `var' is not used
+input.y:1.9-11: warning: %define variable `var' is not used
+]])
+
+AT_CLEANUP
+