[svn] r5934: nemerle/trunk/ncc: hierarchy/TypeBuilder.n testsuite/negative/tyvars.n

[malekith]

Log:
Flag duplicate tyvars (including ones from nesting types) as error. Resolves #536.

Author: malekith
Date: Mon Nov 14 23:05:43 2005
New Revision: 5934

Added:
   nemerle/trunk/ncc/testsuite/negative/tyvars.n
Modified:
   nemerle/trunk/ncc/hierarchy/TypeBuilder.n

Modified: nemerle/trunk/ncc/hierarchy/TypeBuilder.n
==============================================================================
--- nemerle/trunk/ncc/hierarchy/TypeBuilder.n	(original)
+++ nemerle/trunk/ncc/hierarchy/TypeBuilder.n	Mon Nov 14 23:05:43 2005
@@ -986,7 +986,14 @@
     // after we updated parsed tenvs of types with partial parts
     // we should copy them to nested types
     // we do this using parsetrees, so the fresh StaticVars are used
-    unless (this.pt_tydecl.typarms == null)
+    unless (this.pt_tydecl.typarms == null) {
+      def ht = Hashtable ();
+
+      foreach (tv in this.pt_tydecl.typarms.tyvars)
+        if (ht.Contains (tv))
+          Message.Error ($ "duplicate type parameter `$(tv [0])'")
+        else ht [tv] = tv;
+        
       match (this.pt_tydecl) {
         | PT.TopDeclaration.Class (_, decls)
         | PT.TopDeclaration.Variant (_, decls) =>
@@ -996,6 +1003,16 @@
             else {
               def tp1 = this.pt_tydecl.typarms;
               def tp2 = x.typarms;
+              foreach (tv in tp2.tyvars)
+                when (ht.Contains (tv)) {
+                  Message.Error (x.loc,
+                                 $ "type parameter `$(tv [0])' has the same "
+                                   "name as type parameter from the outer "
+                                   "type `$(this)'");
+                  Message.Hint ("type parameters are inherited in nested "
+                                "types and can be used without declaring "
+                                "them explicitly");
+                }
               x.typarms =
                 PT.Typarms (tp1.tyvars + tp2.tyvars, 
                             tp1.constraints + tp2.constraints)
@@ -1003,6 +1020,7 @@
           }
         | _ => () 
       }
+    }
 
     match (pt_tydecl) {
       | PT.TopDeclaration.VariantOption (members) =>

Added: nemerle/trunk/ncc/testsuite/negative/tyvars.n
==============================================================================
--- (empty file)
+++ nemerle/trunk/ncc/testsuite/negative/tyvars.n	Mon Nov 14 23:05:43 2005
@@ -0,0 +1,6 @@
+class A [a, a] { } // E: duplicate type parameter `a'
+
+class B [x] {
+  class C [x] { // E: type parameter `x' has the same name as type parameter from the outer type `B'
+  }
+}