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JIT: two stack-allocated arrays in one statement crash the process #133523
Description
Repro
using System;
using System.Runtime.CompilerServices;
class Program {
[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
static int Test(int index) {
int[] first = new int[3];
int[] second = new int[3];
return first[second[index]];
}
static void Main() {
Console.WriteLine(Test(0));
}
}Expected
0
Actual
Fatal error.
0xC0000005
at Program.Main()
Platform
Windows x64, .NET 11.0.0-rc.1.26425.128. Does not reproduce on .NET 10.
Activity
dotnet-policy-service commentedon Sep 9, 2026
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EgorBo commentedon Sep 9, 2026
cc @AndyAyersMS might be something recent in Escape Analysis?
EgorBo commentedon Sep 9, 2026
yeah, looks like a bug in fgExpandStackArrayAllocations, let me file a fix
JIT: expand all stack array allocations in a statement (#133531)