OpenGL ES 2.x: Bind both `GL_TEXTURE_2D` and `GL_TEXTURE_CUBE_MAP` in the same texture image unit?

I haven't found anything that describes if you can bind a 2D texture and a cube map texture in the same texture unit, but (or so) I guess this is perfectly possible. It makes sense to allow it, since all texture modification functions require you to specify the texture target to operate on, anyway.

But the OpenGL ES 2 spec explicitly disallows to use both at the same time in a shader, as chapter 2.10 says:

It is not allowed to have variables of different sampler types pointing to the same texture image unit within a program object. This situation can only be detected at the next rendering command issued, and an INVALID_OPERATION error will then be generated.

So you cannot use both a sampler2D and a samplerCube referring to the same texture unit to bend your implementation's texture unit limits.