test/tint/buffer/uniform/std140/unnested/mat4x4_f32/dynamic_index_via_ptr.wgsl

@group(0) @binding(0) var<uniform> m : mat4x4<f32>;

var<private> counter = 0;
fn i() -> i32 { counter++; return counter; }

@compute @workgroup_size(1)
fn f() {
  let p_m   = &m;
  let p_m_i = &((*p_m)[i()]);

  let l_m   : mat4x4<f32> = *p_m;
  let l_m_i : vec4<f32>   = *p_m_i;
}