### Compilation failed:

error: 1: invalid type
layout(binding=0) uniform sampler2D test2D;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: 2: invalid type
layout(binding=1) uniform sampler2D test2DRect;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: 4: 'main' must return: 'vec4', 'float4', or 'half4'
void main() {
^^^^^^^^^^^
error: 5: unknown identifier 'sk_FragColor'
    sk_FragColor = sample(test2D, float2(0.5));
    ^^^^^^^^^^^^
error: 5: unknown identifier 'sample'
    sk_FragColor = sample(test2D, float2(0.5));
                   ^^^^^^
error: 6: unknown identifier 'sk_FragColor'
    sk_FragColor = sample(test2DRect, float2(0.5));
    ^^^^^^^^^^^^
error: 6: unknown identifier 'sample'
    sk_FragColor = sample(test2DRect, float2(0.5));
                   ^^^^^^
error: 7: unknown identifier 'sk_FragColor'
    sk_FragColor = sample(test2DRect, float3(0.5));
    ^^^^^^^^^^^^
error: 7: unknown identifier 'sample'
    sk_FragColor = sample(test2DRect, float3(0.5));
                   ^^^^^^
9 errors