Index: generic/predefined.h
===================================================================
diff -u -r147831f1098cb9b96a28d4d5b0f9f3ccea35b9da -r901ceb8f58714e31d28ed3277923fc69c085d252
--- generic/predefined.h	(.../predefined.h)	(revision 147831f1098cb9b96a28d4d5b0f9f3ccea35b9da)
+++ generic/predefined.h	(.../predefined.h)	(revision 901ceb8f58714e31d28ed3277923fc69c085d252)
@@ -150,8 +150,6 @@
 "::xotcl::relation ::xotcl::ObjectParameterSlot superclass ::xotcl::Slot\n"
 "::xotcl::MetaSlot create ::xotcl::MethodParameterSlot\n"
 "::xotcl::relation ::xotcl::MethodParameterSlot superclass ::xotcl::Slot\n"
-"foreach cmd [info command ::xotcl::cmd::MethodParameterSlot::*] {\n"
-"::xotcl::alias ::xotcl::MethodParameterSlot [namespace tail $cmd] $cmd}\n"
 "::xotcl::MethodParameterSlot create ::xotcl::methodParameterSlot\n"
 "proc createBootstrapAttributeSlots {class definitions} {\n"
 "if {![::xotcl::is ${class}::slot object]} {\n"
@@ -439,7 +437,19 @@
 "foreach arg $arglist {\n"
 "::xotcl::Attribute createFromParameterSyntax [self] {*}$arg}\n"
 "::xotcl::setinstvar [::xotcl::self]::slot __parameter $arglist}\n"
-"proc createBootstrapAttributeSlots {} {}}\n"
+"proc createBootstrapAttributeSlots {} {}\n"
+"::xotcl::Slot method type=mixin {name value arg} {\n"
+"if {![::xotcl::is $value mixin $arg]} {\n"
+"error \"Value '$value' of $name has not mixin $arg\"}\n"
+"return $value}\n"
+"::xotcl::Slot method type=baseclass {name value} {\n"
+"if {![::xotcl::is $value baseclass]} {\n"
+"error \"Value '$value' of $name is not a baseclass\"}\n"
+"return $value}\n"
+"::xotcl::Slot method type=metaclass {name value} {\n"
+"if {![::xotcl::is $value metaclass]} {\n"
+"error \"Value '$value' of $name is not a metaclass\"}\n"
+"return $value}}\n"
 "::xotcl2::Class create ::xotcl::ScopedNew -superclass ::xotcl2::Class -parameter {\n"
 "{withclass ::xotcl2::Object}\n"
 "container}\n"