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.