fix #20473 - Struct with both bitfields and a slice or class doesn't compile

[ibuclaw]

This was caused by the compiler-generated xtoHash function which inserted code that took the address of the bit-field. This patch adds a new conditional code path to the generated code that stores the value to a temporary before calling getHash().

Tested by adding injected code into test file.

struct S
{
    char[] slice;
    bool flag : 1;
    size_t toHash() const { ... }
}

Which generates.

/*unrolled*/ {
    {
        enum ulong i = 0LU;
        alias T = const(char[]);
        h = h * 33LU + typeid(const(char[])).getHash(cast(const(void*))&p.slice);
    }
    {
	enum ulong i = 1LU;
	alias T = const(bool);
	const const(bool) t = p.flag;
	h = h * 33LU + typeid(const(bool)).getHash(& t);
    }
}

[dlang-bot]

Thanks for your pull request, @ibuclaw!

Bugzilla references

Your PR doesn't reference any Bugzilla issue.

If your PR contains non-trivial changes, please reference a Bugzilla issue or create a manual changelog.

⚠️⚠️⚠️ Warnings ⚠️⚠️⚠️

• In preparation for migrating from Bugzilla to GitHub Issues, the issue reference syntax has changed. Please add the word "Bugzilla" to issue references. For example, Fix Bugzilla Issue 12345 or Fix Bugzilla 12345.(Reminder: the edit needs to be done in the Git commit message, not the GitHub pull request.)

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#21651"