anchor.diff:  			     c_tuple([#c_literal{val=case_clause},Fpat])),
   	    %% Do a novars little optimisation here.
   	    {Filc,Fps,St} = novars(Fil0, St2),
  -	    {#icase{anno=LAnno,
  +	    {#icase{anno=CGAnno,
   		    args=[Filc],
   		    clauses=[#iclause{anno=LAnno,
   				      pats=[#c_literal{anno=LA,val=true}],
  
positive.code:     %% Special case sequences guard tests.
      LA = lineno_anno(element(2, Fil0), St0),
      LAnno = #a{anno=LA},
      case is_guard_test(Fil0) of
  	true ->
  	    {Gs0,Qs1} = splitwith(fun is_guard_test/1, Qs0),
  	    {Bc,Bps,St1} = bc_tq1(Line, E, Qs1, AccVar, St0),
  	    {Gs,St} = lc_guard_tests([Fil0|Gs0], St1), %These are always flat!
  	    {#icase{anno=LAnno,
  		    args=[],
  		    clauses=[#iclause{anno=LAnno,
  				      pats=[],
  
negative.code: 			     c_tuple([#c_literal{val=case_clause},Fpat])),
  	    %% Do a novars little optimisation here.
  	    {Filc,Fps,St3} = novars(Fil0, St2),
  	    {#icase{anno=CGAnno,
  		    args=[Filc],
  		    clauses=[#iclause{anno=LAnno,
  				      pats=[#c_literal{anno=LA,val=true}],
  