Make PARAMETRIZE_TYPE errors a bit less LTA

rakudo · Jul 8, 2013 · c52f245 · c52f245
1 parent 5b9d80b
commit c52f245
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Showing 2 changed files with 15 additions and 4 deletions.
diff --git a/src/core/Array.pm b/src/core/Array.pm
@@ -141,8 +141,13 @@ class Array {
         }
         # XXX some methods to come here...
     }
-    method PARAMETERIZE_TYPE(Mu $t) {
-        self but TypedArray[$t.WHAT]
+    method PARAMETERIZE_TYPE(Mu $t, |c) {
+        if c.elems == 0 {
+            self but TypedArray[$t.WHAT]
+        }
+        else {
+            die "Can only type-constraint Array with [ValueType]"
+        }
     }
 }
 

diff --git a/src/core/Hash.pm b/src/core/Hash.pm
@@ -280,9 +280,15 @@ my class Hash {
         }
     }
     method PARAMETERIZE_TYPE(Mu $t, |c) {
-        c.elems ??
-            self but TypedHash[$t.WHAT, c[0]] !!
+        if c.elems == 0 {
             self but TypedHash[$t.WHAT]
+        }
+        elsif c.elems == 1 {
+            self but TypedHash[$t.WHAT, c[0]]
+        }
+        else {
+            die "Can only type-constraint Hash with [ValueType] or [ValueType,KeyType]";
+        }
     }
 }