[project @ 2001-01-15 07:33:02 by qrczak]

[ghc-hetmet.git] / ghc / interpreter / static.c

diff --git a/ghc/interpreter/static.c b/ghc/interpreter/static.c
index 16fad26..7636dd7 100644 (file)
--- a/ghc/interpreter/static.c
+++ b/ghc/interpreter/static.c
@@ -9,8 +9,8 @@
  * included in the distribution.
  *
  * $RCSfile: static.c,v $
- * $Revision: 1.40 $
- * $Date: 2000/04/07 10:00:28 $
+ * $Revision: 1.42 $
+ * $Date: 2000/06/02 16:19:47 $
  * ------------------------------------------------------------------------*/
 
 #include "hugsbasictypes.h"
@@ -1322,6 +1322,10 @@ Class c; {
        }
     }
 
+    /* add in the tyvars from the `supers' so that we don't
+       prematurely complain about undefined tyvars */
+    tyvars = typeVarsIn(cclass(c).supers,NIL,NIL,tyvars);
+
     if (cclass(c).arity==0) {
        cclass(c).head = c;
     } else {
@@ -1335,6 +1339,23 @@ Class c; {
 
     tcDeps             = NIL;          /* find dependents                 */
     map2Over(depPredExp,cclass(c).line,tyvars,cclass(c).supers);
+
+    {   /* depPredExp instantiates class names to class structs, so
+         * now we have enough info to check for ambiguity
+         */
+       List tvts = offsetTyvarsIn(cclass(c).head,NIL);
+       List tvps = offsetTyvarsIn(cclass(c).supers,NIL);
+       List fds  = calcFunDeps(cclass(c).supers);
+       tvts = oclose(fds,tvts);
+       tvts = odiff(tvps,tvts);
+
+       if (!isNull(tvts)) {
+           ERRMSG(cclass(c).line) "Undefined type variable \"%s\"",
+             textToStr(textOf(nth(offsetOf(hd(tvts)),tyvars)))
+           EEND;
+       }
+    }
+
     h98CheckCtxt(cclass(c).line,"class definition",FALSE,cclass(c).supers,NIL);
     cclass(c).numSupers = length(cclass(c).supers);
     cclass(c).defaults  = extractBindings(cclass(c).members);   /* defaults*/
@@ -1515,9 +1536,6 @@ Cell  m; {
     thd3(m) = t;                                /* Save type               */
     take(cclass(c).arity,tyvars);               /* Delete extra type vars  */
 
-    if (isAmbiguous(t)) {
-        ambigError(line,"class declaration",hd(vs),t);
-    }
     h98CheckType(line,"member type",hd(vs),t);
 }
 
@@ -1527,6 +1545,10 @@ Cell  m; {
     Int  line = intOf(fst3(m));
     List vs   = snd3(m);
     Type t    = thd3(m);
+
+    if (isAmbiguous(t)) {
+        ambigError(line,"class declaration",hd(vs),t);
+    }
 }
 
 static Void local addMembers(c)         /* Add definitions of member funs  */