Error code on decompiled file

[danthespal]

Input code

.class private auto ansi Configurator
    extends [System.Runtime]System.Object
{
    // Nested Types
    .class nested private auto ansi sealed serializable beforefieldinit '<>c'
        extends [System.Runtime]System.Object
    {
        .custom instance void [System.Runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = (
            01 00 00 00
        )
        // Fields
        .field public static initonly class Configurator/'<>c' '<>9'
        .field public static class [System.Runtime]System.Func`2<class [System.Diagnostics.Process]System.Diagnostics.ProcessModule, bool> '<>9__1_0'

        // Methods
        .method private hidebysig specialname rtspecialname static 
            void .cctor () cil managed 
        {
            // Method begins at RVA 0x3d234
            // Header size: 1
            // Code size: 11 (0xb)
            .maxstack 8

            IL_0000: newobj instance void Configurator/'<>c'::.ctor()
            IL_0005: stsfld class Configurator/'<>c' Configurator/'<>c'::'<>9'
            IL_000a: ret
        } // end of method '<>c'::.cctor

        .method public hidebysig specialname rtspecialname 
            instance void .ctor () cil managed 
        {
            // Method begins at RVA 0x3d240
            // Header size: 1
            // Code size: 7 (0x7)
            .maxstack 8

            IL_0000: ldarg.0
            IL_0001: call instance void [System.Runtime]System.Object::.ctor()
            IL_0006: ret
        } // end of method '<>c'::.ctor

        .method assembly hidebysig 
            instance bool '<InjectCoreClr>b__1_0' (
                class [System.Diagnostics.Process]System.Diagnostics.ProcessModule x
            ) cil managed 
        {
            // Method begins at RVA 0x3d248
            // Header size: 1
            // Code size: 17 (0x11)
            .maxstack 8

            IL_0000: ldarg.1
            IL_0001: callvirt instance string [System.Diagnostics.Process]System.Diagnostics.ProcessModule::get_ModuleName()
            IL_0006: ldstr "coreclr.dll"
            IL_000b: call bool [System.Runtime]System.String::op_Equality(string, string)
            IL_0010: ret
        } // end of method '<>c'::'<InjectCoreClr>b__1_0'

    } // end of class <>c

    // Methods
    .method public hidebysig static pinvokeimpl("kernel32.dll" nomangle lasterr winapi) 
        bool marshal(bool) VirtualProtect (
            [in] native int lpAddress,
            uint64 dwSize,
            uint32 flNewProtect,
            [out] uint32& lpflOldProtect
        ) cil managed preservesig 
    {
    } // end of method Configurator::VirtualProtect

    .method public hidebysig static 
        void Configure (
            uint32[] dynamicKeys,
            uint32 staticKey
        ) cil managed 
    {
        .custom instance void [System.Runtime]System.Runtime.CompilerServices.NullableContextAttribute::.ctor(uint8) = (
            01 00 01 00 00
        )
        // Method begins at RVA 0x3cbe8
        // Header size: 12
        // Code size: 361 (0x169)
        .maxstack 5
        .locals init (
            [0] class [System.Diagnostics.Process]System.Diagnostics.ProcessModule,
            [1] uint8&,
            [2] valuetype [System.Runtime]System.ReadOnlySpan`1<uint8>,
            [3] valuetype [System.Runtime]System.Nullable`1<uint8>[],
            [4] valuetype [System.Runtime]System.Nullable`1<int64>,
            [5] native int,
            [6] uint8&,
            [7] valuetype [System.Runtime]System.Span`1<uint8>,
            [8] native int,
            [9] valuetype [System.Runtime]System.Span`1<uint8>,
            [10] class [System.Collections]System.Collections.Generic.List`1<uint8>,
            [11] native int,
            [12] valuetype [System.Runtime]System.Span`1<uint8>,
            [13] valuetype [System.Runtime]System.ReadOnlySpan`1<uint8>,
            [14] valuetype [System.Runtime]System.Span`1<uint8>,
            [15] uint8[],
            [16] uint32,
            [17] valuetype [System.Runtime]System.ReadOnlySpan`1<uint8>,
            [18] valuetype [System.Runtime]System.Nullable`1<uint8>,
            [19] int64,
            [20] valuetype [System.Runtime]System.ReadOnlySpan`1<uint8>,
            [21] bool,
            [22] valuetype [System.Runtime]System.ReadOnlySpan`1<uint8>&,
            [23] int32,
            [24] valuetype [System.Runtime]System.Nullable`1<int32>,
            [25] valuetype [System.Runtime]System.Nullable`1<int32>,
            [26] int32,
            [27] uint32,
            [28] valuetype [System.Runtime]System.ReadOnlySpan`1<uint8>
        )

        IL_0000: call class [System.Diagnostics.Process]System.Diagnostics.Process [System.Diagnostics.Process]System.Diagnostics.Process::GetCurrentProcess()
        IL_0005: callvirt instance class [System.Diagnostics.Process]System.Diagnostics.ProcessModuleCollection [System.Diagnostics.Process]System.Diagnostics.Process::get_Modules()
        // loop start (head: IL_000a)
            IL_000a: dup
            IL_000b: brtrue.s IL_000a
        // end loop
        IL_000d: pop
        IL_000e: dup
        IL_000f: stloc.0
        IL_0010: ldloc.0
        IL_0011: stloc.1
        IL_0012: ldloc.1
        IL_0013: ldloc.0
        IL_0014: stloc.2
        IL_0015: dup
        IL_0016: conv.u1
        IL_0017: dup
        IL_0018: initobj valuetype [System.Runtime]System.Nullable`1<uint8>
        IL_001e: dup
        IL_001f: initobj valuetype [System.Runtime]System.Nullable`1<uint8>
        IL_0025: dup
        IL_0026: conv.u1
        IL_0027: dup
        IL_0028: initobj valuetype [System.Runtime]System.Nullable`1<uint8>
        IL_002e: dup
        IL_002f: conv.u1
        IL_0030: dup
        IL_0031: initobj valuetype [System.Runtime]System.Nullable`1<uint8>
        IL_0037: dup
        IL_0038: conv.u1
        IL_0039: stloc.3
        IL_003a: initobj valuetype [System.Runtime]System.Nullable`1<int64>
        IL_0040: ldc.i4.0
        // loop start (head: IL_0041)
            IL_0041: conv.i8
            IL_0042: br.s IL_0041
        // end loop
        IL_0044: conv.i4
        IL_0045: sub
        IL_0046: ldloc.3
        IL_0047: ldc.i4.0
        // loop start (head: IL_0048)
            IL_0048: ldelem valuetype [System.Runtime]System.Nullable`1<uint8>
            IL_004d: brtrue.s IL_0048
        // end loop
        // loop start (head: IL_004f)
            IL_004f: initobj valuetype [System.Runtime]System.Nullable`1<int32>
            IL_0055: br.s IL_004f
        // end loop
        IL_0057: ldc.i4.0
        IL_0058: ldind.u1
        IL_0059: ceq
        // loop start (head: IL_005b)
            IL_005b: and
            IL_005c: brfalse.s IL_005b
        // end loop
        IL_005e: ldloc.3
        IL_005f: dup
        IL_0060: ldlen
        IL_0061: conv.i4
        IL_0062: ldc.i4.1
        IL_0063: sub
        // loop start (head: IL_0064)
            IL_0064: ldelem valuetype [System.Runtime]System.Nullable`1<uint8>
            IL_0069: brtrue.s IL_0064
        // end loop
        // loop start (head: IL_006b)
            IL_006b: initobj valuetype [System.Runtime]System.Nullable`1<int32>
            IL_0071: br.s IL_006b
        // end loop
        IL_0073: ldloc.3
        IL_0074: ldlen
        IL_0075: conv.i4
        IL_0076: ldc.i4.1
        IL_0077: sub
        IL_0078: ldind.u1
        IL_0079: ceq
        // loop start (head: IL_007b)
            IL_007b: and
            IL_007c: brfalse.s IL_007b
        // end loop
        IL_007e: ldc.i4.1
        // loop start (head: IL_007f)
            IL_007f: ldc.i4.0
            IL_0080: br.s IL_007f
        // end loop
        IL_0082: ldloc.3
        // loop start (head: IL_0083)
            IL_0083: ldelema valuetype [System.Runtime]System.Nullable`1<uint8>
            IL_0088: brfalse.s IL_0083
        // end loop
        IL_008a: ldloc.3
        // loop start (head: IL_008b)
            IL_008b: ldelem valuetype [System.Runtime]System.Nullable`1<uint8>
            IL_0090: brtrue.s IL_008b
        // end loop
        // loop start (head: IL_0092)
            IL_0092: initobj valuetype [System.Runtime]System.Nullable`1<int32>
            IL_0098: br.s IL_0092
        // end loop
        IL_009a: ldind.u1
        IL_009b: ceq
        // loop start (head: IL_009d)
            IL_009d: and
            IL_009e: brtrue.s IL_009d
        // end loop
        // loop start (head: IL_00a0)
            IL_00a0: ldc.i4.0
            IL_00a1: br.s IL_00a0
        // end loop
        IL_00a3: ldc.i4.1
        IL_00a4: add
        IL_00a5: ldloc.3
        IL_00a6: ldlen

        IL_00a7: conv.i4

        IL_00a8: blt.s IL_00a7
        // loop start (head: IL_00aa)
            IL_00aa: brfalse.s IL_00a8

            IL_00ac: br.s IL_00aa
        // end loop

        IL_00ae: ldc.i4.1
        IL_00af: conv.i8
        IL_00b0: add

        IL_00b1: conv.i8
        // loop start (head: IL_00b2)
            IL_00b2: blt.s IL_00b1

            IL_00b4: brtrue.s IL_00b2
        // end loop
        IL_00b6: ret

        IL_00b7: ldc.i4.2
        IL_00b8: conv.i8
        IL_00b9: add
        IL_00ba: ldloc.1
        IL_00bb: ldarg.0
        IL_00bc: ldc.i4.0
        IL_00bd: dup
        IL_00be: dup
        IL_00bf: dup
        IL_00c0: dup
        IL_00c1: dup
        IL_00c2: dup
        IL_00c3: dup
        IL_00c4: ldc.i4.s 15
        IL_00c6: dup
        IL_00c7: ldc.i4.0
        IL_00c8: dup
        IL_00c9: ldc.i4.s 118
        IL_00cb: dup
        IL_00cc: ldc.i4.s 30
        IL_00ce: dup
        IL_00cf: ldc.i4.s 72
        IL_00d1: dup
        IL_00d2: dup
        IL_00d3: dup
        IL_00d4: dup
        IL_00d5: dup
        IL_00d6: dup
        IL_00d7: ldc.i4.s 120
        IL_00d9: dup
        IL_00da: ldc.i4.s 86
        IL_00dc: dup
        IL_00dd: ldc.i4.s 52
        IL_00df: dup
        IL_00e0: ldc.i4.s 18
        IL_00e2: dup
        IL_00e3: dup
        IL_00e4: dup
        IL_00e5: ldc.i4.0
        IL_00e6: dup
        IL_00e7: ldc.i4.0
        IL_00e8: dup
        IL_00e9: ldc.i4.0
        IL_00ea: dup
        IL_00eb: dup
        IL_00ec: dup
        IL_00ed: dup
        IL_00ee: ldc.i4.s 15
        IL_00f0: dup
        IL_00f1: dup
        IL_00f2: dup
        IL_00f3: ldc.i4.4
        IL_00f4: dup
        IL_00f5: ldc.i4.s 51
        IL_00f7: dup
        IL_00f8: ldc.i4.4
        IL_00f9: dup
        IL_00fa: dup
        IL_00fb: ldc.i4.s 53
        IL_00fd: dup
        IL_00fe: ldc.i4.s 120
        IL_0100: dup
        IL_0101: ldc.i4.s 86
        IL_0103: dup
        IL_0104: ldc.i4.s 52
        IL_0106: dup
        IL_0107: ldc.i4.s 18
        IL_0109: dup
        IL_010a: ldc.i4.0
        IL_010b: dup
        IL_010c: ldc.i4.0
        IL_010d: dup
        IL_010e: ldc.i4.0
        IL_010f: dup
        IL_0110: ldc.i4.0
        IL_0111: dup
        IL_0112: ldc.i4.0
        IL_0113: dup
        IL_0114: ldc.i4.0
        IL_0115: dup
        IL_0116: ldc.i4.0
        IL_0117: dup
        IL_0118: ldc.i4.0
        IL_0119: dup
        IL_011a: ldc.i4.0
        IL_011b: dup
        IL_011c: ldc.i4.0
        IL_011d: dup
        IL_011e: ldc.i4.0
        IL_011f: dup
        IL_0120: ldc.i4.0
        IL_0121: dup
        IL_0122: ldc.i4.0
        IL_0123: dup
        IL_0124: ldc.i4.0
        IL_0125: dup
        IL_0126: dup
        IL_0127: dup
        IL_0128: dup
        IL_0129: ldc.i4.s 72
        IL_012b: dup
        IL_012c: dup
        IL_012d: dup
        IL_012e: dup
        IL_012f: dup
        IL_0130: dup
        IL_0131: ldc.i4.s 120
        IL_0133: dup
        IL_0134: ldc.i4.s 86
        IL_0136: dup
        IL_0137: ldc.i4.s 52
        IL_0139: dup
        IL_013a: ldc.i4.s 18
        IL_013c: dup
        IL_013d: dup
        IL_013e: conv.i8
        IL_013f: ldc.i4.s 64
        IL_0141: pop
        IL_0142: ldc.i4.1
        IL_0143: ldc.i4.s 12
        IL_0145: ldc.i4.8
        IL_0146: ldc.i4.s 14
        IL_0148: ldc.i4.s 14
        IL_014a: newarr [System.Runtime]System.Byte
        IL_014f: ldc.i4.s 40
        IL_0151: ldc.i4.s 14
        IL_0153: ldc.i4.1
        IL_0154: ldc.i4.s 36
        IL_0156: ldc.i4.4
        IL_0157: ldloc.0
        IL_0158: add
        IL_0159: ldc.i4.s 14
        IL_015b: conv.i8
        IL_015c: ldc.i4.s 64
        IL_015e: pop
        IL_015f: ldc.i4.1
        IL_0160: ldc.i4.4
        IL_0161: ldc.i4.8
        IL_0162: ldloc.0
        IL_0163: add
        IL_0164: ldc.i4.s 14
        IL_0166: conv.i8
        IL_0167: pop
        IL_0168: ret
    } // end of method Configurator::Configure

} // end of class Configurator

Erroneous output

// GameHelper, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
// Configurator
using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

internal class Configurator
{
    [DllImport("kernel32.dll", ExactSpelling = true, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool VirtualProtect([In] nint lpAddress, ulong dwSize, uint flNewProtect, out uint lpflOldProtect);

    public unsafe static void Configure(uint[] dynamicKeys, uint staticKey)
    {
        //IL_003a: Expected O, but got I4
        //IL_0041->IL0041: Incompatible stack types: I4 vs I8
        ProcessModuleCollection modules = Process.GetCurrentProcess().Modules;
        while (modules != null)
        {
        }
        ProcessModule processModule = (ProcessModule)/*Error near IL_000e: Stack underflow*/;
        ref ? reference = ref *(?*)processModule;
        ReadOnlySpan<byte> readOnlySpan = (ReadOnlySpan<byte>)processModule;
        byte num = (byte)(ref reference);
        *(byte?*)(int)num = null;
        *(byte?*)(int)num = null;
        byte num2 = num;
        *(byte?*)(int)num2 = null;
        byte num3 = num2;
        *(byte?*)(int)num3 = null;
        byte?[] array = (byte?[])num3;
        *(long?*)(int)num3 = null;
        long num4 = 0L;
        while (true)
        {
            num4 = num4;
        }
    }
}

If the output fails to re-compile, provide the compiler error message. If the output has the wrong behavior, explain how it differs from the expected behavior.

Details

• Product in use: e.g. ILSpy
• Version in use: e.g. 9.0.0.7660-preview2
• Any other relevant information to the issue, or your interest in contributing a fix.

[siegfriedpammer]

The code you provided looks like it's obfuscated and therefore it's difficult to provide a correct decompilation. Keep in mind that the runtime is allowed to entirely ignore unreachable parts of the IL - at runtime the code results in an infinite loop and all instructions after offset 0xb are ignored.