source file modify race leads to inconsistent error message

I got this odd error message from ghc:

Command/AddUrl.hs:120:32: error:
    lexical error in string/character literal at character '-'
    |
120 |                 BatchNull -> '\0'
    |                                ^

Part of the error message says that '-' is the problem character, but the quoted line of code does not contain that.

What happened is I started the build, noticed I had typoed '\-' and quickly corrected it in my editor and saved. It seems ghc must have read the source file twice, so I raced it and so experienced this inconsistency.

I wonder if it could display the wrong line entirely if a larger change was made to the file?

Thanks for your time with such a minor thing as this bug.

Trac metadata

Trac field	Value
Version	8.2.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	low
Resolution	Unresolved
Component	Compiler
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