菜鸟问题，高手来帮帮忙吧

colourmeat

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External code file (doppler_shift) compilation failed
Source code was unavailable to the compiler
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Object repository construction failed
External code file (doppler_shift) compilation failed, no source code found.
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Error encountered rebuilding repository -- unable to proceed
遇到了上面这个问题，现在我想找doppler_shift这个变量，看看是不是没有对它赋值，应该去哪里找？