# Objective
Fix#1727Fix#8010
Meta types generated by the `SystemParam` and `WorldQuery` derive macros
can conflict with user-defined types if they happen to have the same
name.
## Solution
In order to check if an identifier would conflict with user-defined
types, we can just search the original `TokenStream` passed to the macro
to see if it contains the identifier (since the meta types are defined
in an anonymous scope, it's only possible for them to conflict with the
struct definition itself). When generating an identifier for meta types,
we can simply check if it would conflict, and then add additional
characters to the name until it no longer conflicts with anything.
The `WorldQuery` "Item" and read-only structs are a part of a module's
public API, and thus it is intended for them to conflict with
user-defined types.
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