Steps to repro:
1. Download attached project
2. open scene "SampleScene" and enter playmode
3. observe crash
4. in Vertex.cs, change "VertexAttribute.Position, VertexAttributeFormat.Float16, 4" to "VertexAttribute.Position, VertexAttributeFormat.Float32, 4"
5. open scene "SampleScene" and enter playmode
6. observe mesh renders, no crash

Expected: mesh renders using half-precision vertex position
Actual: crash

Reproduced in: 2020.1.0a6, 2019.3.0b5, 2019.3.0b3 (d0377b9426dc), 2019.3.0b1 (78e106a973e1), 2019.3.0a12 (b073d123dd5d), 2019.3.0a11 (6fa9444d8a5d),
2019.3.0a7 (ec42ba0792fd)

Note: Could not reproduce on lower version due to scripting errors - lowest version applicable for this user project is 2019.3.0a7 (because VertexAttributeDescriptor usage)