Crash in QString::section() with QRegExp and SectionIncludeLeadingSep

When using

QString section ( const QRegExp &reg, int start, int end = -1,
SectionFlags flags = SectionDefault ) const

with QString::SectionIncludeLeadingSep as flags and accessing an
element which is non-existing (e.g. start=1 and end=1, where the reg
will result in only a single result), the method call will crash; see
example code in the mail attached.