Bar of exclusion of oral evidence by documentary evidence under Section 91 and 92 of the Indian Evidence Act, 1872 applies:
1
when fact to be proved would invalidate the document.
2
when fact to be proved shows in what manner the language of a document was related to existing facts.
3
when fact to be proved relates to want or failure of consideration.
4
when fact to be proved relates to terms of a contract reduced in form of a document.