Cannot assign to variable outside of declaration block; left-hand-side variable origin=data
Illegal statement beginning with non-void expression parsed as
  u[i]
error in 'modelfa47d7036a9_bayesquantileestimation' at line 36, column 4
  -------------------------------------------------
    34:   c~normal(0,1.0E-4);
    35:   for(i in 1:N){
    36:     u[i]=y[i]-a-b*X1[i]-c*X2[i];
           ^
    37:     h[i]=0;
  -------------------------------------------------
第一次在R用stan，请问各位大佬这是怎么错了？