avoid-slur not set?

[Jay Anderson]

Running the following lilypond file:
-----
\version "2.9.21"

\score
{
 \new Staff
 {
   \relative c'
   {
     c8-.( d-- e-> f-^ g-+ a-_ b-| c-\open) |
     c,8-\espressivo( d-\upbow e-\downbow f-\trill g-\thumb a-\lheel
b-\rheel c-\turn) |
   }
 }
 \layout
 {
   ragged-right = ##t
 }
}
-----

I get the following warnings (not to mention collisions):
-----
bug3.ly:9:21: warning: Ignoring grob for slur. avoid-slur not set?
     c8-.( d-- e-> f
                    -^ g-+ a-_ b-| c-\open) |
bug3.ly:9:25: warning: Ignoring grob for slur. avoid-slur not set?
     c8-.( d-- e-> f-^ g
                        -+ a-_ b-| c-\open) |
bug3.ly:10:53: warning: Ignoring grob for slur. avoid-slur not set?
     c,8-\espressivo( d-\upbow e-\downbow f-\trill g
                                                    -\thumb a-\lheel
b-\rheel c-\turn) |
bug3.ly:10:62: warning: Ignoring grob for slur. avoid-slur not set?
     c,8-\espressivo( d-\upbow e-\downbow f-\trill g-\thumb a
                                                             -\lheel
b-\rheel c-\turn) |
bug3.ly:10:71: warning: Ignoring grob for slur. avoid-slur not set?
     c,8-\espressivo( d-\upbow e-\downbow f-\trill g-\thumb a-\lheel b

-\rheel c-\turn) |
bug3.ly:10:80: warning: Ignoring grob for slur. avoid-slur not set?
     c,8-\espressivo( d-\upbow e-\downbow f-\trill g-\thumb a-\lheel
b-\rheel c -\turn) |[2]
-----

I can understand not having all of these set, but the marcato '^',
stopped '+', thumb, and turn ought to have some sort of default. In a
few of my files I've been doing the following to get around this:

\override Script #'avoid-slur = #'inside

But I'm not sure this is the best work around. Thanks for the help.

-----Horndude77