Delphi 2009 sp1
i receive invalid pointer operation.
Conditions
DataSet contains one calculated widestringfield
code:
mdsRules.DeclareVariable('SETID', otString);
v := '0000000001';
mdsRules.SetVariable('SETID', v);
mdsRules.Open;
v := null; << here is error
workaround: replace widestringfield to stringfield

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Please, answer.

We have not been able to reproduce this.