Optimization removes necessary code #103477
Description
Description
A NativeAOT version of our project fails at runtime while the related managed version works. There are not publishing warnings and static analysis warnings.
The root cause is that the publishing removes some required code. The code is simple without reflection or any similar dynamic techniques.
Reproduction Steps
Program.cs
namespace AotIssue
{
internal class Program
{
static void Main(string[] args)
{
string s = "12151";
int i = 0;
char? a = null;
while (true)
{
string? res = get(s, ref i, ref a);
if (res != null)
{
Console.Write(res);
a = null; // !!! this line is removed from the published version
// Console.Write(a); // uncomment the line for the workaround
continue;
}
if (i >= s.Length)
break;
a = '.';
}
}
static string? get(string s, ref int index, ref char? a)
{
if (index >= s.Length)
return null;
if (a == '.')
return ".";
a ??= s[index++];
return (a == '1') ? "1" : null;
}
}
}AotIssue.csproj
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net8.0</TargetFramework>
<ImplicitUsings>enable</ImplicitUsings>
<Nullable>enable</Nullable>
<PublishAot>true</PublishAot>
<InvariantGlobalization>true</InvariantGlobalization>
<IsAotCompatible>true</IsAotCompatible>
</PropertyGroup>
</Project>To publish the project, you can use the dotnet publish -r win-x64 -c Release command. Or similar publish profile:
<?xml version="1.0" encoding="utf-8"?>
<!--
https://go.microsoft.com/fwlink/?LinkID=208121.
-->
<Project>
<PropertyGroup>
<Configuration>Release</Configuration>
<Platform>Any CPU</Platform>
<PublishDir>bin\Release\net8.0\publish\win-x64\</PublishDir>
<PublishProtocol>FileSystem</PublishProtocol>
<_TargetId>Folder</_TargetId>
<TargetFramework>net8.0</TargetFramework>
<RuntimeIdentifier>win-x64</RuntimeIdentifier>
<SelfContained>true</SelfContained>
<PublishSingleFile>false</PublishSingleFile>
<PublishReadyToRun>false</PublishReadyToRun>
</PropertyGroup>
</Project>Expected behavior
The AOT version prints "1.1.1" like regular .NET version.
Actual behavior
The AOT version prints an infinite sequence of "1111111111111...". The loop never ends.
Regression?
No response
Known Workarounds
Uncomment the line Console.Write(a);. In this case, the code works as expected after publishing.
Configuration
I reproduced the issue in the .NET 8 project with win-x64 target platform on Windows 10.
Other information
The line a = null; is removed from the published version.
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