Desugared:
Test.z :: [(Char, Char, Char, Char, Char, Char, Char, Char, Char, Char)]
Test.z =
    let
      {- CoRec -}
      ds.136 =
	  \ ds.137 ->
	      case ds.137 of {
		Nil ->
		    Nil (Char,
			 Char,
			 Char,
			 Char,
			 Char,
			 Char,
			 Char,
			 Char,
			 Char,
			 Char)
		(:) ds.138 ds.139 ->
		    let a.140 = ds.138
		    in 
		      let
			{- CoRec -}
			ds.141 =
			    \ ds.142 ->
				case ds.142 of {
				  Nil -> ds.136 ds.139
				  (:) ds.143 ds.144 ->
				      let b.145 = ds.143
				      in 
					let
					  {- CoRec -}
					  ds.146 =
					      \ ds.147 ->
						  case ds.147 of {
						    Nil -> ds.141 ds.144
						    (:) ds.148 ds.149 ->
							let c.150 = ds.148
							in 
							  let
							    {- CoRec -}
							    ds.151 =
								\ ds.152 ->
								    case
									ds.152
								    of {
								      Nil ->
									  ds.146
									      ds.149
								      (:) ds.153
									  ds.154 ->
									  let
									    d.155 =
										ds.153
									  in 
									    let
									      {- CoRec -}
									      ds.156 =
										  \ ds.157 ->
										      case
											  ds.157
										      of {
											Nil ->
											    ds.151
												ds.154
											(:) ds.158
											    ds.159 ->
											    let
											      e.160 =
												  ds.158
											    in 
											      let
												{- CoRec -}
												ds.161 =
												    \ ds.162 ->
													case
													    ds.162
													of {
													  Nil ->
													      ds.156
														  ds.159
													  (:) ds.163
													      ds.164 ->
													      let
														f.165 =
														    ds.163
													      in 
														let
														  {- CoRec -}
														  ds.166 =
														      \ ds.167 ->
															  case
															      ds.167
															  of {
															    Nil ->
																ds.161
																    ds.164
															    (:) ds.168
																ds.169 ->
																let
																  g.170 =
																      ds.168
																in 
																  let
																    {- CoRec -}
																    ds.171 =
																	\ ds.172 ->
																	    case
																		ds.172
																	    of {
																	      Nil ->
																		  ds.166
																		      ds.169
																	      (:) ds.173
																		  ds.174 ->
																		  let
																		    h.175 =
																			ds.173
																		  in 
																		    let
																		      {- CoRec -}
																		      ds.176 =
																			  \ ds.177 ->
																			      case
																				  ds.177
																			      of {
																				Nil ->
																				    ds.171
																					ds.174
																				(:) ds.178
																				    ds.179 ->
																				    let
																				      i.180 =
																					  ds.178
																				    in 
																				      let
																					{- CoRec -}
																					ds.181 =
																					    \ ds.182 ->
																						case
																						    ds.182
																						of {
																						  Nil ->
																						      ds.176
																							  ds.179
																						  (:) ds.183
																						      ds.184 ->
																						      let
																							j.185 =
																							    ds.183
																						      in 
																							(: (Char,
																							    Char,
																							    Char,
																							    Char,
																							    Char,
																							    Char,
																							    Char,
																							    Char,
																							    Char,
																							    Char))
																							    (MkTuple10!
																								 Char
																								 Char
																								 Char
																								 Char
																								 Char
																								 Char
																								 Char
																								 Char
																								 Char
																								 Char
																								 a.140
																								 b.145
																								 c.150
																								 d.155
																								 e.160
																								 f.165
																								 g.170
																								 h.175
																								 i.180
																								 j.185)
																							    (ds.181
																								 ds.184)
																						}
																					{- end CoRec -}
																				      in 
																					ds.181
																					    "12"S
																			      }
																		      {- end CoRec -}
																		    in 
																		      ds.176
																			  "12"S
																	    }
																    {- end CoRec -}
																  in 
																    ds.171
																	"12"S
															  }
														  {- end CoRec -}
														in 
														  ds.166
														      "12"S
													}
												{- end CoRec -}
											      in 
												ds.161
												    "12"S
										      }
									      {- end CoRec -}
									    in 
									      ds.156
										  "12"S
								    }
							    {- end CoRec -}
							  in  ds.151 "12"S
						  }
					  {- end CoRec -}
					in  ds.146 "12"S
				}
			{- end CoRec -}
		      in  ds.141 "12"S
	      }
      {- end CoRec -}
    in  ds.136 "12"S