Issue #13998 has been reported by ko1 (Koichi Sasada).

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Bug #13998: BOM disables "mismatched indentations" warning
https://bugs.ruby-lang.org/issues/13998

* Author: ko1 (Koichi Sasada)
* Status: Open
* Priority: Normal
* Assignee: nobu (Nobuyoshi Nakada)
* Target version: 2.5
* ruby -v: Ruby 2.3 and later.
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN
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`ruby -w` doesn't show "mismatched indentations" when scripts containing BOM.
This issue occurs on Ruby 2.3 and later.



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