Avoid using non-ASCII Unicode characters outside of comments and literals

In error-prone 2.11.0 I’ve started getting the following error when building within IntelliJ

Foo.java:17:2
java: [UnicodeInCode] Avoid using non-ASCII Unicode characters outside of comments and literals, as they can be confusing.
    (see https://errorprone.info/bugpattern/UnicodeInCode)

When I view the file in VIM or HexDump there I can’t see any non-unicode characters.

Line 17 is the end of the file, I can’t supply the whole file due to work constraints. But below is a screenshot of the end of the file from hexedit

Within IntelliJ the formatter is doing

If I down grade error-prone to 2.10.0 it works fine on the offending file

[chashnikov]

I’ve found the cause: Javac modifies content of file passed to it as char[] (see UnicodeReader.java:103) by replacing the last character by 0x1a. If this array is cached (the original implementation of Javac also does that, but code in intellij does this in a different way to improve performance), Error Prone may get this modified content and report an error. Note that this code in Javac was rewritten as part of JDK-8224225, so the problem shouldn’t appear in Java 16 and newer versions.

[elefeint]

FYI, there is an issue filed on the IntelliJ side, too – https://youtrack.jetbrains.com/issue/IDEA-288257