Compute Shader compile error from Texture3D.Sample()

I’m trying to sample a 3D noise texture that I generate elsewhere and pass to my ComputeShader. However, when compiling the following, all I get is “Shader error in ‘DensityGenerator.compute’: cannot map expression to cs_5_0 instruction set at DensityGenerator.compute(14) (on d3d11)”.

I really haven’t got a clue where to start with this. It looks right and the only way to get it to compile is to comment out line 14 (noiseVol.Sample(), specifically).

What obvious bug have I missed?

#pragma kernel Density

Texture3D<float4>         noiseVol;
SamplerState              samplerNoiseVol;
RWStructuredBuffer<float> voxels;

void Density (uint3 threadId : SV_DispatchThreadID, uint3 groupId : SV_GroupID)
	int size = 32;
	int3 voxPos   = threadId; // Just rename this for the sake of clarity

	float density = 0;//-voxPos.y;
	density += noiseVol.Sample(samplerNoiseVol, voxPos, 0).z;
	voxels[voxPos.x + voxPos.y*size + voxPos.z*size*size] = density;

Just ran into the same problem, so for anyone coming across this problem in the future, replacing

Texture.Sample(sampler, pos);


Texture.SampleLevel(sampler, pos, 0); //The 0 at the end is the mip level

fixed it for me