doc is required

Author: gfldex

doc/Language/typesystem.pod6

@@ -243,9 +243,20 @@ public attributes of that class.
     my $c = C.new.a = 42;
     dd $c; # OUTPUT«Int $c = 42␤»
 
-=head3 trait C<is required>
+=head3 X«trait C<is required>|is required»
 
-TODO
+Defined as:
+
+    multi sub trait_mod:<is>(Attribute $attr, :$required!)
+
+Marks a class or roles attribute as required. If the attribute is not
+initialized at object construction time throws
+L<X::Attribute::Required|/type/X::Attribute::Required>.
+
+    class C { has $.attr is required; }
+    C.new;
+    CATCH { default { say .^name => .Str } }
+    # OUTPUT«X::Attribute::Required => The attribute '$!attr' is required, but you did not provide a value for it.␤»
 
 =head3 trait C<does>