X-Git-Url: http://git.lukelau.me/?a=blobdiff_plain;f=typecheck.scm;h=b3466751fdf7f4161963d3904c13f970b8798a76;hb=0db4aa6c791e5ed27bfd9c4461e7a5337ee699e1;hp=064f65f696459d08b38f3e20e00f8ff180b23bc7;hpb=e66dabdbc34b1bf5d59cf2596ced19525661a378;p=scheme.git

diff --git a/typecheck.scm b/typecheck.scm
index 064f65f..b346675 100644
--- a/typecheck.scm
+++ b/typecheck.scm
@@ -191,6 +191,16 @@
 (define (check-case dls env x)
 
   (define (check-match switch-type x)
+    
+    (define (get-bindings product-types pattern)
+      (define (go product-type product)
+	     (case (ast-type x)
+	       ['var (list (cons product product-type))]
+					; an inner pattern match
+	       ['app (get-bindings product-type product)]))
+      (flat-map go product-types (cdr pattern)))
+
+    
     (let ([pattern (car x)]
 	  [expr (cadr x)])
       (case (ast-type pattern)
@@ -199,8 +209,8 @@
 	  (let ([sum (assoc (car pattern) (cdr (assoc switch-type dls)))])
 	    (unless sum (error #f "can't pattern match ~a with ~a" switch-type pattern))
 	    (let* ([names (cdr pattern)]
-		   [types (cdr sum)]
-		   [new-env (fold-left env-insert env names types)])
+		   [product-types (cdr sum)]
+		   [new-env (append (get-bindings product-types pattern) env)])
 	      (check dls new-env expr)))]
 					; pattern match with binding and no constructor
 	['var (check dls (env-insert env pattern switch-type) expr)]
@@ -219,7 +229,7 @@
 
 	 [resolved-type (substitute case-expr-equality-cs (car case-expr-types))]
 
-	 [annotated `((case (,(case-switch x) : ,switch-type)
+	 [annotated `((case ,(caddr switch-type-res)
 			,@(map (lambda (c e et)
 				 `(,c ((,e : ,et))))
 			       (map car (case-cases x))