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Comparers don't work for messy generic corner cases #89767
Description
Compile the repro below with/without optimizations.
Without optimizations, this prints:
Here
False
True
That's good.
With optimizations, this prints:
Here
False
Here
False
That's not so good.
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
{
MyStruct<object, object> s1 = default;
MyStruct<object, object> s2 = default;
Console.WriteLine(Equals(s1, s2));
}
{
MyStruct<object, string> s1 = default;
MyStruct<object, string> s2 = default;
Console.WriteLine(Equals(s1, s2));
}
[MethodImpl(MethodImplOptions.NoInlining)]
static bool Equals<T>(T x, T y)
{
return EqualityComparer<T>.Default.Equals(x, y);
}
struct MyStruct<T, U> : IEquatable<MyStruct<U, U>>
{
public bool Equals(MyStruct<U, U> other)
{
Console.WriteLine("Here");
return false;
}
}
Activity
MichalStrehovsky commentedon Aug 1, 2023
(To be clear, this issue is not for Native AOT, it's broken for JIT scenarios. It's also broken on Native AOT but I'm going to wait until there's a defined behavior for this, defined by the JIT side.)
jakobbotsch commentedon Aug 1, 2023
What is the non-NAOT repro case? This one doesn't seem to repro without NativeAOT for me.
jakobbotsch commentedon Aug 1, 2023
(Seems like it was failing just recently until #88006. Also #88006 (comment) looks related.)
JulieLeeMSFT commentedon Aug 1, 2023
@EgorBo PTAL. CC @jkotas.
jkotas commentedon Aug 1, 2023
This is a bug in native AOT implementation of JIT/EE interface. I will take a look.
Fix optimizations for comparers corner cases in native AOT
MichalStrehovsky commentedon Aug 2, 2023
I would have sworn I tested it with the latest installer build but probably fell into the trap of having something else on PATH. Sorry for the noise.
Fix optimizations for comparers corner cases in native AOT (#89829)