RexToLixTranslation can generate code with many redundant structures

String sql = "with \"t\" as (select case "
        + "when \"store_id\" = 1 then '1' "
        + "when \"store_id\" = 2 then '2' "
        + "when \"store_id\" = 3 then '3' "
        + "when \"store_id\" = 4 then '4' "
        + "else '0' end as \"myid\" from (values (1),(2),(3),(6)) as \"tt\"(\"store_id\"))\n"
        + "select case "
        + "when \"myid\" = '1' then '11' "
        + "when \"myid\" = '2' then '22' "
        + "when \"myid\" = '3' then '33' "
        + "when \"myid\" = '4' then '44' "
        + "else '0' end as \"res\" from \"t\"";
    CalciteAssert.that()
        .query(sql)
        .returns("res=11\\nres=22\\nres=33\\nres=0 \\n");

/*   1 */ public org.apache.calcite.linq4j.Enumerable bind(final org.apache.calcite.DataContext root) {
/*   2 */   final org.apache.calcite.linq4j.Enumerable _inputEnumerable = org.apache.calcite.linq4j.Linq4j.asEnumerable(new Integer[] {
/*   3 */     1,
/*   4 */     2,
/*   5 */     3,
/*   6 */     6});
/*   7 */   return new org.apache.calcite.linq4j.AbstractEnumerable(){
/*   8 */       public org.apache.calcite.linq4j.Enumerator enumerator() {
/*   9 */         return new org.apache.calcite.linq4j.Enumerator(){
/*  10 */             public final org.apache.calcite.linq4j.Enumerator inputEnumerator = _inputEnumerable.enumerator();
/*  11 */             public void reset() {
/*  12 */               inputEnumerator.reset();
/*  13 */             }
/*  14 */ 
/*  15 */             public boolean moveNext() {
/*  16 */               return inputEnumerator.moveNext();
/*  17 */             }
/*  18 */ 
/*  19 */             public void close() {
/*  20 */               inputEnumerator.close();
/*  21 */             }
/*  22 */ 
/*  23 */             public Object current() {
/*  24 */               String case_when_value;
/*  25 */               String case_when_value0;
/*  26 */               final int current = org.apache.calcite.runtime.SqlFunctions.toInt(inputEnumerator.current());
/*  27 */               if (current == 1) {
/*  28 */                 case_when_value0 = "1";
/*  29 */               } else {
/*  30 */                 if (current == 2) {
/*  31 */                   case_when_value0 = "2";
/*  32 */                 } else {
/*  33 */                   if (current == 3) {
/*  34 */                     case_when_value0 = "3";
/*  35 */                   } else {
/*  36 */                     if (current == 4) {
/*  37 */                       case_when_value0 = "4";
/*  38 */                     } else {
/*  39 */                       case_when_value0 = "0";
/*  40 */                     }
/*  41 */                   }
/*  42 */                 }
/*  43 */               }
/*  44 */               if (case_when_value0 != null && org.apache.calcite.runtime.SqlFunctions.eq(case_when_value0, "1")) {
/*  45 */                 case_when_value = "11";
/*  46 */               } else {
/*  47 */                 String case_when_value1;
/*  48 */                 if (current == 1) {
/*  49 */                   case_when_value1 = "1";
/*  50 */                 } else {
/*  51 */                   if (current == 2) {
/*  52 */                     case_when_value1 = "2";
/*  53 */                   } else {
/*  54 */                     if (current == 3) {
/*  55 */                       case_when_value1 = "3";
/*  56 */                     } else {
/*  57 */                       if (current == 4) {
/*  58 */                         case_when_value1 = "4";
/*  59 */                       } else {
/*  60 */                         case_when_value1 = "0";
/*  61 */                       }
/*  62 */                     }
/*  63 */                   }
/*  64 */                 }
/*  65 */                 if (case_when_value1 != null && org.apache.calcite.runtime.SqlFunctions.eq(case_when_value1, "2")) {
/*  66 */                   case_when_value = "22";
/*  67 */                 } else {
/*  68 */                   String case_when_value2;
/*  69 */                   if (current == 1) {
/*  70 */                     case_when_value2 = "1";
/*  71 */                   } else {
/*  72 */                     if (current == 2) {
/*  73 */                       case_when_value2 = "2";
/*  74 */                     } else {
/*  75 */                       if (current == 3) {
/*  76 */                         case_when_value2 = "3";
/*  77 */                       } else {
/*  78 */                         if (current == 4) {
/*  79 */                           case_when_value2 = "4";
/*  80 */                         } else {
/*  81 */                           case_when_value2 = "0";
/*  82 */                         }
/*  83 */                       }
/*  84 */                     }
/*  85 */                   }
/*  86 */                   if (case_when_value2 != null && org.apache.calcite.runtime.SqlFunctions.eq(case_when_value2, "3")) {
/*  87 */                     case_when_value = "33";
/*  88 */                   } else {
/*  89 */                     String case_when_value3;
/*  90 */                     if (current == 1) {
/*  91 */                       case_when_value3 = "1";
/*  92 */                     } else {
/*  93 */                       if (current == 2) {
/*  94 */                         case_when_value3 = "2";
/*  95 */                       } else {
/*  96 */                         if (current == 3) {
/*  97 */                           case_when_value3 = "3";
/*  98 */                         } else {
/*  99 */                           if (current == 4) {
/* 100 */                             case_when_value3 = "4";
/* 101 */                           } else {
/* 102 */                             case_when_value3 = "0";
/* 103 */                           }
/* 104 */                         }
/* 105 */                       }
/* 106 */                     }
/* 107 */                     if (case_when_value3 != null && org.apache.calcite.runtime.SqlFunctions.eq(case_when_value3, "4")) {
/* 108 */                       case_when_value = "44";
/* 109 */                     } else {
/* 110 */                       case_when_value = "0 ";
/* 111 */                     }
/* 112 */                   }
/* 113 */                 }
/* 114 */               }
/* 115 */               return case_when_value;
/* 116 */             }
/* 117 */ 
/* 118 */           };
/* 119 */       }
/* 120 */ 
/* 121 */     };
/* 122 */ }
/* 123 */ 
/* 124 */ 
/* 125 */ public Class getElementType() {
/* 126 */   return java.lang.String.class;
/* 127 */ }
/* 128 */ 
/* 129 */