class X::Undeclared does X::Comp {}

Thrown when the compiler encounters a symbol that has not been declared, but needs to be.



results in

Variable $x is not declared


method symbol§

Returns the name of the undeclared symbol

method what§

Returns the kind of symbol that was not declared (for example variable, type, routine).

Since The symbol wasn't declared, the compiler sometimes has to guess (or rather disambiguate) what kind of symbol it encounter that wasn't declared. For example if you write

say a;

Then the disambiguation defaults to reporting a missing subroutine, even though declaring a constant a = 'a' would also make the error go away.