C# decompilation uses ternary conditional operator instead of if else, and causes desync on IL with C#.

[iLillie]

Input code

https://github.com/Lightning-Forge-Games/uGUI/blob/8686abb727366154be46c3062c24cfe5183d3d4e/com.unity.ugui/Runtime/TMP/TMP_FontAsset.cs#L619-L625

if (texFormat == TextureFormat.Alpha8)
    tmp_material = new Material(ShaderUtilities.ShaderRef_MobileBitmap);
else
    tmp_material = new Material(Shader.Find("TextMeshPro/Sprite"));

//tmp_material.name = texture.name + " Material";
tmp_material.SetTexture(ShaderUtilities.ID_MainTex, texture);

Erroneous output

Instead of doing if else, it decompiles as ternarny conditional, and desyncs the IL when using mixed.

	// material = ((textureFormat != TextureFormat.Alpha8) ? new Material(Shader.Find("TextMeshPro/Sprite")) : new Material(ShaderUtilities.ShaderRef_MobileBitmap));
	IL_00a8: ldloc.1
	IL_00a9: ldc.i4.1
	IL_00aa: bne.un.s IL_00ba

	IL_00ac: call class [UnityEngine.CoreModule]UnityEngine.Shader TMPro.ShaderUtilities::get_ShaderRef_MobileBitmap()
	IL_00b1: newobj instance void [UnityEngine.CoreModule]UnityEngine.Material::.ctor(class [UnityEngine.CoreModule]UnityEngine.Shader)
	IL_00b6: stloc.s 4
	// (no C# code)
	IL_00b8: br.s IL_00cb

	// material.SetTexture(ShaderUtilities.ID_MainTex, texture2D);
	IL_00ba: ldstr "TextMeshPro/Sprite"
	IL_00bf: call class [UnityEngine.CoreModule]UnityEngine.Shader [UnityEngine.CoreModule]UnityEngine.Shader::Find(string)
	IL_00c4: newobj instance void [UnityEngine.CoreModule]UnityEngine.Material::.ctor(class [UnityEngine.CoreModule]UnityEngine.Shader)
	IL_00c9: stloc.s 4

	IL_00cb: ldloc.s 4
	IL_00cd: ldsfld int32 TMPro.ShaderUtilities::ID_MainTex
	IL_00d2: ldloc.2
	IL_00d3: callvirt instance void [UnityEngine.CoreModule]UnityEngine.Material::SetTexture(int32, class [UnityEngine.CoreModule]UnityEngine.Texture)

Expected decompilation

Example is from using DnSpyEx v6.5.1

Details

• Product in use: ILSpy 10.0 Preview 2
• Version in use: Latest one, but same problem is also on older versions.
• The correct behaviour happens on DnSpyEx.

[siegfriedpammer]

It's a non-goal of the decompiler engine to reproduce the exact input code in every case. The code you show in "expected decompilation" doesn't even have an if statement.

[iLillie]

Here is a better picture of expected decompilation, that shows the entire code with the if statement

It's a non-goal of the decompiler engine to reproduce the exact input code in every case. The code you show in "expected decompilation" doesn't even have an if statement.

I understand, but in this case it causes desync when using "IL with C#" mode 😅 and causes the next decompiled code to be rendered earlier than it should.

	// material.SetTexture(ShaderUtilities.ID_MainTex, texture2D);
	IL_00ba: ldstr "TextMeshPro/Sprite"
	IL_00bf: call class [UnityEngine.CoreModule]UnityEngine.Shader [UnityEngine.CoreModule]UnityEngine.Shader::Find(string)
	IL_00c4: newobj instance void [UnityEngine.CoreModule]UnityEngine.Material::.ctor(class [UnityEngine.CoreModule]UnityEngine.Shader)
	IL_00c9: stloc.s 4