Identifiers in patterns should be checked against literals using bound-identifier=?, not free-identifier=?.

lib/init-7.scm

@@ -728,7 +728,7 @@
            _let (list (list v x))
            (cond
             ((identifier? p)
-             (if (any (lambda (l) (compare p l)) lits)
+             (if (memq p lits)
                  (list _and
                        (list _compare v (list _rename (list _quote p)))
                        (k vars))

tests/r7rs-tests.scm

@@ -556,6 +556,15 @@
     42)
   (test 42 (quux399)))
 
+(let-syntax
+    ((m (syntax-rules ()
+          ((m x) (let-syntax
+                     ((n (syntax-rules (k)
+                           ((n x) 'bound-identifier=?)
+                           ((n y) 'free-identifier=?))))
+                   (n z))))))
+  (test 'bound-identifier=? (m k)))
+
 (test-end)
 
 (test-begin "5 Program structure")