[Bug other/61321] demangler crash on casts in template parameters

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #1 from Pedro Alves <palves at redhat dot com> ---
I think we need to distinguish conversion operators from expression casts.  

Working on a patch that adds:

--- c/include/demangle.h
+++ w/include/demangle.h
@@ -373,6 +373,10 @@ enum demangle_component_type
   /* A typecast, represented as a unary operator.  The one subtree is
      the type to which the argument should be cast.  */
   DEMANGLE_COMPONENT_CAST,
+  /* A conversion operator, represented as a unary operator.  The one
+     subtree is the type to which the argument should be converted
+     to.  */
+  DEMANGLE_COMPONENT_CONVERSION,