compiler.tree.identities: the identity on mod was useless too, because we already have a rewrite rule which handles this case in compiler.tree.propagation

basis/compiler/tree/identities/identities.factor

@@ -29,10 +29,6 @@ SYMBOL: X
     { { 0 X } drop }
 } define-identities
 
-\ mod {
-    { { X 1 } 0 }
-} define-identities
-
 \ bitand {
     { { X -1 } drop }
     { { -1 X } nip }

basis/compiler/tree/modular-arithmetic/modular-arithmetic-tests.factor

@@ -134,6 +134,12 @@ TUPLE: declared-fixnum { x fixnum } ;
     ] { mod fixnum-mod rem } inlined?
 ] unit-test
 
+[ [ drop 0 ] ]
+[ [ >integer 1 rem ] test-modular-arithmetic ] unit-test
+
+[ [ drop 0 ] ]
+[ [ >integer 1 mod ] test-modular-arithmetic ] unit-test
+
 [ [ >fixnum 255 >R R> fixnum-bitand ] ]
 [ [ >integer 256 rem ] test-modular-arithmetic ] unit-test