Add subtyping for dotted lists with the same bound.

2010-05-24 14:22:23 -04:00 · 2010-05-24 14:22:23 -04:00 · 62fb6f9311
commit 62fb6f9311
parent 40dbb6389c
1 changed files with 3 additions and 0 deletions
--- a/collects/typed-scheme/types/subtype.rkt
+++ b/collects/typed-scheme/types/subtype.rkt
@ -295,6 +295,9 @@
 	      [((Pair: a d) (Pair: a* d*))
 	       (let ([A1 (subtype* A0 a a*)])
 		 (and A1 (subtype* A1 d d*)))]
+              ;; recur structurally on dotted lists, assuming same bounds
+              [((ListDots: s-dty dbound) (ListDots: t-dty dbound))
+               (subtype* A0 s-dty t-dty)]
 	      ;; quantification over two types preserves subtyping
 	      [((Poly: ns b1) (Poly: ms b2)) 
 	       (=> unmatch)