The problem occured in context with #4618 (see comment 32) and is explained by the following code:
sage: L.<x> = LaurentSeriesRing(QQ)
sage: q = x^2 + x^3
sage: q.add_bigoh(-1)
Traceback (most recent call last):
...
ValueError: prec (= -3) must be non-negative
CC: @tscrim
Component: algebra
Keywords: Laurent series precision days100
Author: Sebastian Oehms
Branch/Commit: 14878d5
Reviewer: Travis Scrimshaw
Issue created by migration from https://trac.sagemath.org/ticket/28239