## E0152: legacy octal literals may not contain underscores

A legacy octal literal is a `0` digit followed by one or more octal digits (`0` through `7`). It is a syntax error for a legacy octal literal to contain a digit separator (`_`):

    let fileMode = 01_755;

To fix this error, begin the literal with `0o`:

    let fileMode = 0o1_755;

Alternatively, remove the underscore:

    let fileMode = 01755;

Documentation for other errors