[clang] [Sema] Compare canonical conversion function (PR #154158)

[Vassil Vassilev via cfe-commits]

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@@ -0,0 +1,143 @@
+// RUN: rm -rf %t
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vgvassilev wrote:

I'd start from something like:
```cpp
typedef int (*ifn)();
struct F {
  operator ifn();
};

int main() {
  int i1 = 0;
  ifn pfn = i1 ? F() : main;
}
```

That would get us into the branch we added. I looked briefly at this test and it seems we pull the two different operators through ADL (there are some namespaces and friend functions involved.) Perhaps we could enhance our `F` to turn on such a behavior but I will have to time out for today.

https://github.com/llvm/llvm-project/pull/154158