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author | Paul Phillips <paulp@improving.org> | 2011-01-10 07:21:56 +0000 |
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committer | Paul Phillips <paulp@improving.org> | 2011-01-10 07:21:56 +0000 |
commit | e05dfaeabf430dac8909ff9e5a5911b0c94101ae (patch) | |
tree | 397ce22c41c4c5b95390625ef73fcb70cef856b6 /test/files/neg/tailrec-3.check | |
parent | 58b5c24df8ba06c02b92723922bc21381fedeb93 (diff) | |
download | scala-e05dfaeabf430dac8909ff9e5a5911b0c94101ae.tar.gz scala-e05dfaeabf430dac8909ff9e5a5911b0c94101ae.tar.bz2 scala-e05dfaeabf430dac8909ff9e5a5911b0c94101ae.zip |
A pretty severe bug in the recognition of tail ...
A pretty severe bug in the recognition of tail call elimination.
It turns out that Tailcalls will perform "partial elimination" in
situations such as:
@annotation.tailrec final def f(x: Int): Int = f(f(x))
The outer call to f1 becomes a jump, but the inner call remains as
it was. I implemented @tailrec under the impression that if the
optimization had taken place, it had gone all the way. So this is now
fixed with a direct examination of the rewritten tree.
While I was in there I threw in some improved error reporting: the error
positioning is now on the call which is not in tail position rather than
the method declaration.
Closes #4135, no review.
Diffstat (limited to 'test/files/neg/tailrec-3.check')
-rw-r--r-- | test/files/neg/tailrec-3.check | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/test/files/neg/tailrec-3.check b/test/files/neg/tailrec-3.check new file mode 100644 index 0000000000..a3542fb564 --- /dev/null +++ b/test/files/neg/tailrec-3.check @@ -0,0 +1,10 @@ +tailrec-3.scala:4: error: could not optimize @tailrec annotated method quux: it contains a recursive call not in tail position + @tailrec private def quux(xs: List[String]): List[String] = quux(quux(xs)) + ^ +tailrec-3.scala:6: error: could not optimize @tailrec annotated method quux2: it contains a recursive call not in tail position + case x1 :: x2 :: rest => quux2(x1 :: quux2(rest)) + ^ +tailrec-3.scala:10: error: could not optimize @tailrec annotated method quux3: it contains a recursive call not in tail position + case x :: xs if quux3(List("abc")) => quux3(xs) + ^ +three errors found |