Add a check to ensure that if the formulas originating from the exhaustivity /

reachability analysis are too big to be solved in reasonable time, then we skip
the analysis. I also cleaned up warnings.

Why did `t9181.scala` work fine with 2.11.4, but is now running out of memory?

In order to ensure that the scrutinee is associated only with one of the 400
derived classes we add 400*400 / 2 ~ 80k clauses to ensure mutual exclusivity.

In 2.11.4 the translation into CNF used to fail, since it would blow up already
at this point in memory. This has been fixed in 2.11.5, but now the DPLL solver
is the bottleneck.

There's a check in the search for all models (exhaustivity) that it would avoid
a blow up, but in the search for a model (reachability), such a check is
missing.

3 files changed, 808 insertions, 1 deletions

diff --git a/test/files/pos/t6942.flags b/test/files/pos/t6942.flags
index e8fb65d50c..0f96f1f872 100644
--- a/test/files/pos/t6942.flags
+++ b/test/files/pos/t6942.flags
@@ -1 +1 @@
--Xfatal-warnings
\ No newline at end of file
+-nowarn
\ No newline at end of file
diff --git a/test/files/pos/t9181.flags b/test/files/pos/t9181.flags
new file mode 100644
index 0000000000..0f96f1f872
--- /dev/null
+++ b/test/files/pos/t9181.flags
@@ -0,0 +1 @@
+-nowarn
\ No newline at end of file
diff --git a/test/files/pos/t9181.scala b/test/files/pos/t9181.scala
new file mode 100644
index 0000000000..2edf6fe4a3
--- /dev/null
+++ b/test/files/pos/t9181.scala
@@ -0,0 +1,806 @@
+sealed trait C
+case object C1 extends C
+case object C2 extends C
+case object C3 extends C
+case object C4 extends C
+case object C5 extends C
+case object C6 extends C
+case object C7 extends C
+case object C8 extends C
+case object C9 extends C
+case object C10 extends C
+case object C11 extends C
+case object C12 extends C
+case object C13 extends C
+case object C14 extends C
+case object C15 extends C
+case object C16 extends C
+case object C17 extends C
+case object C18 extends C
+case object C19 extends C
+case object C20 extends C
+case object C21 extends C
+case object C22 extends C
+case object C23 extends C
+case object C24 extends C
+case object C25 extends C
+case object C26 extends C
+case object C27 extends C
+case object C28 extends C
+case object C29 extends C
+case object C30 extends C
+case object C31 extends C
+case object C32 extends C
+case object C33 extends C
+case object C34 extends C
+case object C35 extends C
+case object C36 extends C
+case object C37 extends C
+case object C38 extends C
+case object C39 extends C
+case object C40 extends C
+case object C41 extends C
+case object C42 extends C
+case object C43 extends C
+case object C44 extends C
+case object C45 extends C
+case object C46 extends C
+case object C47 extends C
+case object C48 extends C
+case object C49 extends C
+case object C50 extends C
+case object C51 extends C
+case object C52 extends C
+case object C53 extends C
+case object C54 extends C
+case object C55 extends C
+case object C56 extends C
+case object C57 extends C
+case object C58 extends C
+case object C59 extends C
+case object C60 extends C
+case object C61 extends C
+case object C62 extends C
+case object C63 extends C
+case object C64 extends 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 C200 extends C
+case object C201 extends C
+case object C202 extends C
+case object C203 extends C
+case object C204 extends C
+case object C205 extends C
+case object C206 extends C
+case object C207 extends C
+case object C208 extends C
+case object C209 extends C
+case object C210 extends C
+case object C211 extends C
+case object C212 extends C
+case object C213 extends C
+case object C214 extends C
+case object C215 extends C
+case object C216 extends C
+case object C217 extends C
+case object C218 extends C
+case object C219 extends C
+case object C220 extends C
+case object C221 extends C
+case object C222 extends C
+case object C223 extends C
+case object C224 extends C
+case object C225 extends C
+case object C226 extends C
+case object C227 extends C
+case object C228 extends C
+case object C229 extends C
+case object C230 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
+case object C300 extends C
+case object C301 extends C
+case object C302 extends C
+case object C303 extends C
+case object C304 extends C
+case object C305 extends C
+case object C306 extends C
+case object C307 extends C
+case object C308 extends C
+case object C309 extends C
+case object C310 extends C
+case object C311 extends C
+case object C312 extends C
+case object C313 extends C
+case object C314 extends C
+case object C315 extends C
+case object C316 extends C
+case object C317 extends C
+case object C318 extends C
+case object C319 extends C
+case object C320 extends C
+case object C321 extends C
+case object C322 extends C
+case object C323 extends C
+case object C324 extends C
+case object C325 extends C
+case object C326 extends C
+case object C327 extends C
+case object C328 extends C
+case object C329 extends C
+case object C330 extends C
+case object C331 extends C
+case object C332 extends C
+case object C333 extends C
+case object C334 extends C
+case object C335 extends C
+case object C336 extends C
+case object C337 extends C
+case object C338 extends C
+case object C339 extends C
+case object C340 extends C
+case object C341 extends C
+case object C342 extends C
+case object C343 extends C
+case object C344 extends C
+case object C345 extends C
+case object C346 extends C
+case object C347 extends C
+case object C348 extends C
+case object C349 extends C
+case object C350 extends C
+case object C351 extends C
+case object C352 extends C
+case object C353 extends C
+case object C354 extends C
+case object C355 extends C
+case object C356 extends C
+case object C357 extends C
+case object C358 extends C
+case object C359 extends C
+case object C360 extends C
+case object C361 extends C
+case object C362 extends C
+case object C363 extends C
+case object C364 extends C
+case object C365 extends C
+case object C366 extends C
+case object C367 extends C
+case object C368 extends C
+case object C369 extends C
+case object C370 extends C
+case object C371 extends C
+case object C372 extends C
+case object C373 extends C
+case object C374 extends C
+case object C375 extends C
+case object C376 extends C
+case object C377 extends C
+case object C378 extends C
+case object C379 extends C
+case object C380 extends C
+case object C381 extends C
+case object C382 extends C
+case object C383 extends C
+case object C384 extends C
+case object C385 extends C
+case object C386 extends C
+case object C387 extends C
+case object C388 extends C
+case object C389 extends C
+case object C390 extends C
+case object C391 extends C
+case object C392 extends C
+case object C393 extends C
+case object C394 extends C
+case object C395 extends C
+case object C396 extends C
+case object C397 extends C
+case object C398 extends C
+case object C399 extends C
+case object C400 extends C
+
+object M {
+  def f(c: C): Int = c match {
+    case C1 => 1
+    case C2 => 2
+    case C3 => 3
+    case C4 => 4
+    case C5 => 5
+    case C6 => 6
+    case C7 => 7
+    case C8 => 8
+    case C9 => 9
+    case C10 => 10
+    case C11 => 11
+    case C12 => 12
+    case C13 => 13
+    case C14 => 14
+    case C15 => 15
+    case C16 => 16
+    case C17 => 17
+    case C18 => 18
+    case C19 => 19
+    case C20 => 20
+    case C21 => 21
+    case C22 => 22
+    case C23 => 23
+    case C24 => 24
+    case C25 => 25
+    case C26 => 26
+    case C27 => 27
+    case C28 => 28
+    case C29 => 29
+    case C30 => 30
+    case C31 => 31
+    case C32 => 32
+    case C33 => 33
+    case C34 => 34
+    case C35 => 35
+    case C36 => 36
+    case C37 => 37
+    case C38 => 38
+    case C39 => 39
+    case C40 => 40
+    case C41 => 41
+    case C42 => 42
+    case C43 => 43
+    case C44 => 44
+    case C45 => 45
+    case C46 => 46
+    case C47 => 47
+    case C48 => 48
+    case C49 => 49
+    case C50 => 50
+    case C51 => 51
+    case C52 => 52
+    case C53 => 53
+    case C54 => 54
+    case C55 => 55
+    case C56 => 56
+    case C57 => 57
+    case C58 => 58
+    case C59 => 59
+    case C60 => 60
+    case C61 => 61
+    case C62 => 62
+    case C63 => 63
+    case C64 => 64
+    case C65 => 65
+    case C66 => 66
+    case C67 => 67
+    case C68 => 68
+    case C69 => 69
+    case C70 => 70
+    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 C200 => 200
+    case C201 => 201
+    case C202 => 202
+    case C203 => 203
+    case C204 => 204
+    case C205 => 205
+    case C206 => 206
+    case C207 => 207
+    case C208 => 208
+    case C209 => 209
+    case C210 => 210
+    case C211 => 211
+    case C212 => 212
+    case C213 => 213
+    case C214 => 214
+    case C215 => 215
+    case C216 => 216
+    case C217 => 217
+    case C218 => 218
+    case C219 => 219
+    case C220 => 220
+    case C221 => 221
+    case C222 => 222
+    case C223 => 223
+    case C224 => 224
+    case C225 => 225
+    case C226 => 226
+    case C227 => 227
+    case C228 => 228
+    case C229 => 229
+    case C230 => 230
+    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
+    case C300 => 300
+    case C301 => 301
+    case C302 => 302
+    case C303 => 303
+    case C304 => 304
+    case C305 => 305
+    case C306 => 306
+    case C307 => 307
+    case C308 => 308
+    case C309 => 309
+    case C310 => 310
+    case C311 => 311
+    case C312 => 312
+    case C313 => 313
+    case C314 => 314
+    case C315 => 315
+    case C316 => 316
+    case C317 => 317
+    case C318 => 318
+    case C319 => 319
+    case C320 => 320
+    case C321 => 321
+    case C322 => 322
+    case C323 => 323
+    case C324 => 324
+    case C325 => 325
+    case C326 => 326
+    case C327 => 327
+    case C328 => 328
+    case C329 => 329
+    case C330 => 330
+    case C331 => 331
+    case C332 => 332
+    case C333 => 333
+    case C334 => 334
+    case C335 => 335
+    case C336 => 336
+    case C337 => 337
+    case C338 => 338
+    case C339 => 339
+    case C340 => 340
+    case C341 => 341
+    case C342 => 342
+    case C343 => 343
+    case C344 => 344
+    case C345 => 345
+    case C346 => 346
+    case C347 => 347
+    case C348 => 348
+    case C349 => 349
+    case C350 => 350
+    case C351 => 351
+    case C352 => 352
+    case C353 => 353
+    case C354 => 354
+    case C355 => 355
+    case C356 => 356
+    case C357 => 357
+    case C358 => 358
+    case C359 => 359
+    case C360 => 360
+    case C361 => 361
+    case C362 => 362
+    case C363 => 363
+    case C364 => 364
+    case C365 => 365
+    case C366 => 366
+    case C367 => 367
+    case C368 => 368
+    case C369 => 369
+    case C370 => 370
+    case C371 => 371
+    case C372 => 372
+    case C373 => 373
+    case C374 => 374
+    case C375 => 375
+    case C376 => 376
+    case C377 => 377
+    case C378 => 378
+    case C379 => 379
+    case C380 => 380
+    case C381 => 381
+    case C382 => 382
+    case C383 => 383
+    case C384 => 384
+    case C385 => 385
+    case C386 => 386
+    case C387 => 387
+    case C388 => 388
+    case C389 => 389
+    case C390 => 390
+    case C391 => 391
+    case C392 => 392
+    case C393 => 393
+    case C394 => 394
+    case C395 => 395
+    case C396 => 396
+    case C397 => 397
+    case C398 => 398
+    case C399 => 399
+    case C400 => 400
+  }
+}