(CommandList
  children: [
    (C {(set)} {(-e)})
    (FuncDef
      name: check
      body: 
        (BraceGroup
          children: [
            (Assignment
              keyword: Assign_None
              pairs: [
                (assign_pair
                  lhs: (LhsName name:number_of_occurrence)
                  op: Equal
                  rhs: 
                    {
                      (CommandSubPart
                        command_list: 
                          (CommandList
                            children: [
                              (Pipeline
                                children: [
                                  (C {(grep)} {($ VSub_Number '$2')} {(./) ($ VSub_Number '$1')} {(-o)})
                                  (C {(wc)} {(-l)})
                                ]
                                negated: F
                              )
                            ]
                          )
                        left_token: <Left_Backtick '`'>
                        spids: [78 92]
                      )
                    }
                  spids: [77]
                )
              ]
              spids: [77]
            )
            (If
              arms: [
                (if_arm
                  cond: [
                    (C {(Lit_Other '[')} {($ VSub_Name '$number_of_occurrence')} 
                      {(KW_Bang '!') (Lit_Other '=')} {($ VSub_Number '$3')} {(Lit_Other ']')}
                    )
                  ]
                  action: [
                    (C {(echo)} {(DQ ('String literals were not merged'))})
                    (ControlFlow token:<ControlFlow_Exit exit> arg_word:{(1)})
                  ]
                  spids: [16777215 109]
                )
              ]
              spids: [16777215 124]
            )
          ]
          spids: [74]
        )
      spids: [70 73]
    )
    (C {(check)} {(merge_string_literals.stdout)} {(DQ (abcd))} {(2)})
  ]
)