Loop in compiler in SB-C::ARRAY-TYPE-UPGRADED-ELEMENT-TYPE

[Paul F. Dietz]

(lambda (p1 p2 p3 p4 p6)
  (declare (optimize (speed 2) (debug 1))
           (type (satisfies eval) p2)
           (type (member :from-end 2) p3))
  (position p1
            (the (member #(10 20) 3) p2)
            (the (member 1 :from-end) p3)
            (the null p4)
            :test-not
            p6))

==> compiler loops; interrupt gives:

Interactive interrupt at #x21C531B4.
   [Condition of type SB-SYS:INTERACTIVE-INTERRUPT]

Restarts:
 0: [CONTINUE] Return from SB-UNIX:SIGINT.
 1: [ABORT] Exit debugger, returning to top level.

Backtrace:
  0: (SB-KERNEL::%TYPE-UNION (#<SB-KERNEL:MEMBER-TYPE NULL>))
  1: (SB-C::ARRAY-TYPE-UPGRADED-ELEMENT-TYPE #<SB-KERNEL:MEMBER-TYPE NULL>)
  2: (SB-C::ARRAY-TYPE-UPGRADED-ELEMENT-TYPE #<SB-KERNEL:INTERSECTION-TYPE (AND (SATISFIES EVAL) NULL)>)
  3: (SB-C::ARRAY-TYPE-UPGRADED-ELEMENT-TYPE #<SB-KERNEL:UNION-TYPE (OR (AND #1=(SATISFIES EVAL) CONS) (AND #1# NULL) (AND #1# VECTOR) (AND #1# SB-KERNEL:EXTENDED-SEQUENCE))>)
  4: (SB-C::DERIVE-AREF-TYPE #<SB-C::LVAR 1 {100D6CC8F3}>)
  5: ((FLET SB-C::PROCESS-INFO :IN SB-C::IR1-OPTIMIZE-COMBINATION))
  6: (SB-C::IR1-OPTIMIZE-COMBINATION #<SB-C::COMBINATION :FUN #<SB-C::REF :LEAF #<SB-C::GLOBAL-VAR :%SOURCE-NAME SB-KERNEL:DATA-VECTOR-REF-WITH-OFFSET :TYPE #1=#<SB-KERNEL:FUN-TYPE #> :DEFINED-TYPE #1# :W..
  7: (SB-C::IR1-OPTIMIZE-BLOCK #<SB-C::CBLOCK 12 :START c2 {100D6B90A3}>)
  8: (SB-C::IR1-OPTIMIZE #<SB-C:COMPONENT :NAME (LAMBDA (P1 P2 P3 P4 P6)) :REANALYZE T {100D526923}> NIL)
  9: (SB-C::IR1-OPTIMIZE-UNTIL-DONE #<SB-C:COMPONENT :NAME (LAMBDA (P1 P2 P3 P4 P6)) :REANALYZE T {100D526923}>)
 10: (SB-C::IR1-PHASES #<SB-C:COMPONENT :NAME (LAMBDA (P1 P2 P3 P4 P6)) :REANALYZE T {100D526923}>)
 11: (SB-C::COMPILE-COMPONENT #<SB-C:COMPONENT :NAME (LAMBDA (P1 P2 P3 P4 P6)) :REANALYZE T {100D526923}>)

[Stas Boukarev (stassats)]

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