[Bug-apl] Overtake on Left of Assignment

[Mike Duvos]

      A←'' ⋄ (↑A)←0

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-- Stack trace at Cell.cc:129
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0x7f0746a36ec5 __libc_start_main
0x443145  main
0x54ee0d   Workspace::immediate_execution(bool)
0x483c92    Command::process_line()
0x483d1b     Command::do_APL_expression(UCS_string&)
0x48df78      Executable::execute_body() const
0x508840       StateIndicator::run()
0x4bc6ce        Prefix::reduce_statements()
0x4bbb8c         Prefix::reduce_MISC_F_B_()
0x4d102b          Bif_F12_TAKE::eval_B(Value_P)
0x4cbbeb           Bif_F12_TAKE::first(Value_P)
0x54c634            Value::prototype(char const*) const
0x4733cc             Cell::init_type(Cell const&, Value&)
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address@hidden:~$