(* cvr: devise comprehensive tests *) (* simple tests *)signature S = sig type t type v sharing type v = t end;structure X = struct type t = int type v = int end :> S;structure Y as S = [structure struct type t = int type v = int end as S];structure Z as S = 	 if true then [structure Y as S] else	 [structure struct type t = bool type v = bool end as S];functor F(X:S)=X:>S;functor G(X:S)=F(F(F(X:S)));functor H(X:S)=X:S:>S:>S:>S; (* elaborate tests *) signature LR_TABLE =    sig        datatype ('a,'b) pairlist = EMPTY | PAIR of 'a * 'b * ('a,'b) pairlist    end;signature TOKEN =    sig	structure LrTable : LR_TABLE    end;signature LR_PARSER =    sig	structure LrTable : LR_TABLE	structure Token : TOKEN	sharing LrTable = Token.LrTable    end;signature PARSER_DATA =   sig	structure LrTable : LR_TABLE	structure Token : TOKEN	sharing Token.LrTable = LrTable    end;signature PARSER =    sig        structure Token : TOKEN     end; functor Join(structure ParserData: PARSER_DATA	     structure LrParser : LR_PARSER	     sharing ParserData.LrTable = LrParser.LrTable	     sharing ParserData.Token = LrParser.Token	    )		 : PARSER =struct    structure Token = ParserData.Tokenend;structure LrTable : LR_TABLE =     struct 	datatype ('a,'b) pairlist = EMPTY				  | PAIR of 'a * 'b * ('a,'b) pairlistend; structure LrParser :> LR_PARSER =   struct      structure LrTable = LrTable      structure Token : TOKEN =	struct	    structure LrTable = LrTable        end end; signature Fol_LRVALS=    sig	structure ParserData:PARSER_DATA    end;functor FolLrValsFun (structure Token : TOKEN			  ) : Fol_LRVALS =     struct	structure ParserData=	    struct 		structure LrTable = Token.LrTable		structure Token = Token	    end    end;structure FolLrVals : Fol_LRVALS =   FolLrValsFun(structure Token = LrParser.Token);  structure FolParser : PARSER =   Join(structure ParserData = FolLrVals.ParserData	structure LrParser = LrParser);