mesa f84bc57d7dc02fceb805803131426c791eadeff9 broke this test on bxt and skl:

/tmp/build_root/m32/lib/piglit/bin/khr_compressed_astc-array_gl -auto -fbo

Standard Error

Failed to compile fragment shader: 0:4(1): error: No precision specified in this scope for type `sampler2DArray'

source:
#version 300 es
precision highp float;

uniform sampler2DArray tex;
uniform int index;
in vec2 tex_coord;
out vec4 fragment_color;

void main()
{
    vec4 t = texture(tex, vec3(tex_coord.x, tex_coord.y, index));
    fragment_color = vec4(t.rgb, 1.0);
}


Author:     Iago Toral Quiroga <itoral@igalia.com>
AuthorDate: Tue Nov 10 08:22:07 2015 +0200
Commit:     Tapani Pälli <tapani.palli@intel.com>
CommitDate: Thu Nov 12 09:50:13 2015 +0200

    glsl: Add precision information to ir_variable
    
    We will need this later on when we implement proper support for
    precision qualifiers in the drivers and also to do link time checks for
    uniforms as indicated by the spec.
    
    This patch also adds compile-time checks for variables without precision
    information (currently, Mesa only checks that a default precision is set
    for floats in fragment shaders).
    
    As indicated by Ian, the addition of the precision information to
    ir_variable has been done using a bitfield and pahole to identify an
    available hole so that memory requirements for ir_variable stay the
    same.