7266 – [CTFE] Assign to ref param (that's taken from struct member) is noop

-----------------------------------
import std.stdio;
struct S { int a; }
int foo()
{
	S s;
	return bar(s.a); // A
	//bar(s.a); return s.a; // B
}
int bar(ref int b)
{
	b = 5;
	return b;
}
enum y = foo();
void main()
{
	writeln(y);
}
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Expected output: 5
Actual output: 0
Same thing occurs with either the "// A" line or the "// B" line uncommented. Also occurs with "out" instead of "ref".

https://github.com/D-Programming-Language/dmd/commit/1cbd1959e41d39c812a8f4c1a17eb8535d44547a
https://github.com/D-Programming-Language/dmd/commit/1394b3c55c740106555cd484697019e4a9b77109