Erroneous "unterminated slur" message at end of first time bar

[Michael Hendry]

I have written a guitar piece, where the last note of a lead-in bar is followed
by a hammer-on to the first note of the next bar. A slur works fine for this,
except when the passage is repeated and the last note of the first-time repeat
bar is to be hammered-on to the first note of the repeated section.

All the information is there for Lilypond to "know" that the note at the end of
the first-time repeat is to be followed by the first note of the repeated
section, but it obviously doesn't check this.

The following code fragment demonstrates the problem:

\version "2.12.3"
{r2 r4 r8 e( |
\repeat volta 2 {
 a1) |
}
\alternative {
{r2 r4 r8 e( |}
{a1}
}
}

There are similar problems with ties and repeat sections, e.g...

\version "2.12.3"
{r2 r4 r8 e~ |
\repeat volta 2 {
 e1 |
}
\alternative {
{r2 r4 r8 e~ |}
{e1}
}
}

...where the last note of the first-time bar is tied to the first note of the
second-time bar.