[Issue 21190] generated strings should convert to immutable char *

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21190

--- Comment #2 from Steven Schveighoffer <schveiguy at yahoo.com> ---
oof! Yeah, it's not valid, but the bug is still valid. Change p declaration to:

const(char)* p = x;

and you now see the single error for the assignment to x4.

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