wgpu panic: Semantic error due to switch/case with const

panic_shader2.frag

#version 450 core

vec3 i_resolution;
vec4 i_mouse;
float i_time;
float i_time_delta;
int i_frame;

// Shadertoy compatibility, see we can use the same code copied from shadertoy website

#define iTime i_time
#define iResolution i_resolution
#define iTimeDelta i_time_delta
#define iMouse i_mouse
#define iFrame i_frame

#define mainImage shader_main
// 1. declare constant integers

const int ID_left = 0;
const int ID_right = 1;


void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    vec2 uv = 2.0 * fragCoord/iResolution.xy;
    
    int side = int(uv.x);
 
    vec3 col = vec3(0.2);
    
    // 2. switch case on an int
    switch(side)
    {
    // 3. use those constants 
    case ID_left:
    {
        col *= 4.0;
    }
    case ID_right:
    {
        col *= 2.0;
    }
    }

    fragColor = vec4(col,1.0);
}

layout(location = 0) in vec2 uv;

struct ShadertoyInput {
    vec4 mouse;
    vec3 resolution;
    float time;
    float time_delta;
    int frame;
};

layout(binding = 0) uniform ShadertoyInput input;
out vec4 FragColor;
void main(){

    i_time = input.time;
    i_resolution = input.resolution;
    i_time_delta = input.time_delta;
    i_mouse = input.mouse;
    i_frame = input.frame;


    vec2 uv = vec2(uv.x, 1.0 - uv.y);
    vec2 frag_coord = uv * i_resolution.xy;

    shader_main(FragColor, frag_coord);

}