The name of the coercions optimizer in the codes array in opt_wrapper.c is wrong (currently it's "coercion"), and so it is never run.
diff -r 6e9b305e92e2 monetdb5/optimizer/opt_wrapper.c
--- a/monetdb5/optimizer/opt_wrapper.c Sun Feb 10 17:39:23 2013 +0100
+++ b/monetdb5/optimizer/opt_wrapper.c Tue Feb 12 11:33:20 2013 +0000
@@ -84,7 +84,7 @@
{"aliases", &OPTaliasesImplementation},
{"centipede", &OPTcentipedeImplementation},
{"cluster", &OPTclusterImplementation},
- {"coercion", &OPTcoercionImplementation},
+ {"coercions", &OPTcoercionImplementation},
{"commonTerms", &OPTcommonTermsImplementation},
{"compression", &OPTcompressionImplementation},
{"costModel", &OPTcostModelImplementation},