invalid literal in syntax-rules:r6

[higepon]

 ./mosh tests/r7rs/r7rs-tests.scm 
 Condition components:
 1. &who           who: syntax-rules:r6
 2. &message       message: "invalid literal"
 3. &syntax        form: (syntax-rules:r6 (...) ((_ x) '(x ...)))
                   subform: ...

 Exception:
     error in raise: returned from non-continuable exception

 Stack trace:
    1. throw: <subr>
    2. (raise c):  baselib.scm:940
    3. (for-each-1 proc lst):  baselib.scm:124
    4. (lambda (lits pat* tmp*) ...):  psyntax.scm:10
    5. (do-macro-call transformer expr rib):  psyntax.scm:10
    6. (lambda (P3bea P3bec P3bee) ...):  psyntax.scm:10
    7. (dynamic-wind in body out):  baselib.scm:776
    8. (expand-transformer expr r):  psyntax.scm:10
    9. (expand-transformer expr r):  psyntax.scm:10
    10. (lambda (P3e34 P3e36) ...):  psyntax.scm:10
    11. (chi-internal e* r mr):  psyntax.scm:10
    12. (chi-internal e* r mr):  psyntax.scm:10
    13. (lambda (lhs* rhs* b b*) ...):  psyntax.scm:10
    14. (lambda (lhs* rhs* b b*) ...):  psyntax.scm:10
    15. (chi-rhs rhs r mr):  psyntax.scm:10
    16. (chi-rhs rhs r mr):  psyntax.scm:10
    17. (f ls):  psyntax.scm:10
    18. (f ls):  psyntax.scm:10
    19. (f ls):  psyntax.scm:10
    20. (f ls):  psyntax.scm:10
      ... (more stack dump truncated)