module test; import std::collections::map; fn void foo(HashMap{char[], String}* f) { } fn void main() { HashMap{char[], char[]} x; foo(&x); // #error: Implicitly casting 'HashMap{char[], char[]}*' to 'HashMap{char[], String}*' is not permitted, but you may do an explicit cast by placing '(HashMap{char[], String}*)' before the expression }