diff --git a/tests/pos/i1661.scala b/tests/pos/i1661.scala
new file mode 100644
index 000000000000..093a9d1ee284
--- /dev/null
+++ b/tests/pos/i1661.scala
@@ -0,0 +1,413 @@
+sealed trait C
+case object C65 extends C
+case object C66 extends C
+case object C67 extends C
+case object C68 extends C
+case object C69 extends C
+case object C70 extends C
+case object C71 extends C
+case object C72 extends C
+case object C73 extends C
+case object C74 extends C
+case object C75 extends C
+case object C76 extends C
+case object C77 extends C
+case object C78 extends C
+case object C79 extends C
+case object C80 extends C
+case object C81 extends C
+case object C82 extends C
+case object C83 extends C
+case object C84 extends C
+case object C85 extends C
+case object C86 extends C
+case object C87 extends C
+case object C88 extends C
+case object C89 extends C
+case object C90 extends C
+case object C91 extends C
+case object C92 extends C
+case object C93 extends C
+case object C94 extends C
+case object C95 extends C
+case object C96 extends C
+case object C97 extends C
+case object C98 extends C
+case object C99 extends C
+case object C100 extends C
+case object C101 extends C
+case object C102 extends C
+case object C103 extends C
+case object C104 extends C
+case object C105 extends C
+case object C106 extends C
+case object C107 extends C
+case object C108 extends C
+case object C109 extends C
+case object C110 extends C
+case object C111 extends C
+case object C112 extends C
+case object C113 extends C
+case object C114 extends C
+case object C115 extends C
+case object C116 extends C
+case object C117 extends C
+case object C118 extends C
+case object C119 extends C
+case object C120 extends C
+case object C121 extends C
+case object C122 extends C
+case object C123 extends C
+case object C124 extends C
+case object C125 extends C
+case object C126 extends C
+case object C127 extends C
+case object C128 extends C
+case object C129 extends C
+case object C130 extends C
+case object C131 extends C
+case object C132 extends C
+case object C133 extends C
+case object C134 extends C
+case object C135 extends C
+case object C136 extends C
+case object C137 extends C
+case object C138 extends C
+case object C139 extends C
+case object C140 extends C
+case object C141 extends C
+case object C142 extends C
+case object C143 extends C
+case object C144 extends C
+case object C145 extends C
+case object C146 extends C
+case object C147 extends C
+case object C148 extends C
+case object C149 extends C
+case object C150 extends C
+case object C151 extends C
+case object C152 extends C
+case object C153 extends C
+case object C154 extends C
+case object C155 extends C
+case object C156 extends C
+case object C157 extends C
+case object C158 extends C
+case object C159 extends C
+case object C160 extends C
+case object C161 extends C
+case object C162 extends C
+case object C163 extends C
+case object C164 extends C
+case object C165 extends C
+case object C166 extends C
+case object C167 extends C
+case object C168 extends C
+case object C169 extends C
+case object C170 extends C
+case object C171 extends C
+case object C172 extends C
+case object C173 extends C
+case object C174 extends C
+case object C175 extends C
+case object C176 extends C
+case object C177 extends C
+case object C178 extends C
+case object C179 extends C
+case object C180 extends C
+case object C181 extends C
+case object C182 extends C
+case object C183 extends C
+case object C184 extends C
+case object C185 extends C
+case object C186 extends C
+case object C187 extends C
+case object C188 extends C
+case object C189 extends C
+case object C190 extends C
+case object C191 extends C
+case object C192 extends C
+case object C193 extends C
+case object C194 extends C
+case object C195 extends C
+case object C196 extends C
+case object C197 extends C
+case object C198 extends C
+case object C199 extends C
+case object C231 extends C
+case object C232 extends C
+case object C233 extends C
+case object C234 extends C
+case object C235 extends C
+case object C236 extends C
+case object C237 extends C
+case object C238 extends C
+case object C239 extends C
+case object C240 extends C
+case object C241 extends C
+case object C242 extends C
+case object C243 extends C
+case object C244 extends C
+case object C245 extends C
+case object C246 extends C
+case object C247 extends C
+case object C248 extends C
+case object C249 extends C
+case object C250 extends C
+case object C251 extends C
+case object C252 extends C
+case object C253 extends C
+case object C254 extends C
+case object C255 extends C
+case object C256 extends C
+case object C257 extends C
+case object C258 extends C
+case object C259 extends C
+case object C260 extends C
+case object C261 extends C
+case object C262 extends C
+case object C263 extends C
+case object C264 extends C
+case object C265 extends C
+case object C266 extends C
+case object C267 extends C
+case object C268 extends C
+case object C269 extends C
+case object C270 extends C
+case object C271 extends C
+case object C272 extends C
+case object C273 extends C
+case object C274 extends C
+case object C275 extends C
+case object C276 extends C
+case object C277 extends C
+case object C278 extends C
+case object C279 extends C
+case object C280 extends C
+case object C281 extends C
+case object C282 extends C
+case object C283 extends C
+case object C284 extends C
+case object C285 extends C
+case object C286 extends C
+case object C287 extends C
+case object C288 extends C
+case object C289 extends C
+case object C290 extends C
+case object C291 extends C
+case object C292 extends C
+case object C293 extends C
+case object C294 extends C
+case object C295 extends C
+case object C296 extends C
+case object C297 extends C
+case object C298 extends C
+case object C299 extends C
+object M {
+  def f(c: C): Int = c match {
+    case C65 => 65
+    case C66 => 66
+    case C67 => 67
+    case C68 => 68
+    case C69 => 69
+    case C132 => 133
+    case C71 => 71
+    case C72 => 72
+    case C73 => 73
+    case C74 => 74
+    case C75 => 75
+    case C76 => 76
+    case C77 => 77
+    case C78 => 78
+    case C79 => 79
+    case C80 => 80
+    case C81 => 81
+    case C82 => 82
+    case C83 => 83
+    case C84 => 84
+    case C85 => 85
+    case C86 => 86
+    case C87 => 87
+    case C88 => 88
+    case C89 => 89
+    case C90 => 90
+    case C91 => 91
+    case C92 => 92
+    case C93 => 93
+    case C94 => 94
+    case C95 => 95
+    case C96 => 96
+    case C97 => 97
+    case C98 => 98
+    case C99 => 99
+    case C100 => 100
+    case C101 => 101
+    case C102 => 102
+    case C103 => 103
+    case C104 => 104
+    case C105 => 105
+    case C106 => 106
+    case C107 => 107
+    case C108 => 108
+    case C109 => 109
+    case C110 => 110
+    case C111 => 111
+    case C112 => 112
+    case C113 => 113
+    case C114 => 114
+    case C115 => 115
+    case C116 => 116
+    case C117 => 117
+    case C118 => 118
+    case C119 => 119
+    case C120 => 120
+    case C121 => 121
+    case C122 => 122
+    case C123 => 123
+    case C124 => 124
+    case C125 => 125
+    case C126 => 126
+    case C127 => 127
+    case C128 => 128
+    case C129 => 129
+    case C130 => 130
+    case C131 => 131
+    case C132 => 132
+    case C133 => 133
+    case C134 => 134
+    case C135 => 135
+    case C136 => 136
+    case C137 => 137
+    case C138 => 138
+    case C139 => 139
+    case C140 => 140
+    case C141 => 141
+    case C142 => 142
+    case C143 => 143
+    case C144 => 144
+    case C145 => 145
+    case C146 => 146
+    case C147 => 147
+    case C148 => 148
+    case C149 => 149
+    case C150 => 150
+    case C151 => 151
+    case C152 => 152
+    case C153 => 153
+    case C154 => 154
+    case C155 => 155
+    case C156 => 156
+    case C157 => 157
+    case C158 => 158
+    case C159 => 159
+    case C160 => 160
+    case C161 => 161
+    case C162 => 162
+    case C163 => 163
+    case C164 => 164
+    case C165 => 165
+    case C166 => 166
+    case C167 => 167
+    case C168 => 168
+    case C169 => 169
+    case C170 => 170
+    case C171 => 171
+    case C172 => 172
+    case C173 => 173
+    case C174 => 174
+    case C175 => 175
+    case C176 => 176
+    case C177 => 177
+    case C178 => 178
+    case C179 => 179
+    case C180 => 180
+    case C181 => 181
+    case C182 => 182
+    case C183 => 183
+    case C184 => 184
+    case C185 => 185
+    case C186 => 186
+    case C187 => 187
+    case C188 => 188
+    case C189 => 189
+    case C190 => 190
+    case C191 => 191
+    case C192 => 192
+    case C193 => 193
+    case C194 => 194
+    case C195 => 195
+    case C196 => 196
+    case C197 => 197
+    case C198 => 198
+    case C199 => 199
+    case C231 => 231
+    case C232 => 232
+    case C233 => 233
+    case C234 => 234
+    case C235 => 235
+    case C236 => 236
+    case C237 => 237
+    case C238 => 238
+    case C239 => 239
+    case C240 => 240
+    case C241 => 241
+    case C242 => 242
+    case C243 => 243
+    case C244 => 244
+    case C245 => 245
+    case C246 => 246
+    case C247 => 247
+    case C248 => 248
+    case C249 => 249
+    case C250 => 250
+    case C251 => 251
+    case C252 => 252
+    case C253 => 253
+    case C254 => 254
+    case C255 => 255
+    case C256 => 256
+    case C257 => 257
+    case C258 => 258
+    case C259 => 259
+    case C260 => 260
+    case C261 => 261
+    case C262 => 262
+    case C263 => 263
+    case C264 => 264
+    case C265 => 265
+    case C266 => 266
+    case C267 => 267
+    case C268 => 268
+    case C269 => 269
+    case C270 => 270
+    case C271 => 271
+    case C272 => 272
+    case C273 => 273
+    case C274 => 274
+    case C275 => 275
+    case C276 => 276
+    case C277 => 277
+    case C278 => 278
+    case C279 => 279
+    case C280 => 280
+    case C281 => 281
+    case C282 => 282
+    case C283 => 283
+    case C284 => 284
+    case C285 => 285
+    case C286 => 286
+    case C287 => 287
+    case C288 => 288
+    case C289 => 289
+    case C290 => 290
+    case C291 => 291
+    case C292 => 292
+    case C293 => 293
+    case C294 => 294
+    case C295 => 295
+    case C296 => 296
+    case C297 => 297
+    case C298 => 298
+    case C299 => 299
+  }
+}