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author | Jason Zaugg <jzaugg@gmail.com> | 2015-07-07 09:59:24 +1000 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2015-07-07 09:59:24 +1000 |
commit | 30cc2c51036bb0d1bc3c53ff600bfbe62a8be542 (patch) | |
tree | 47878152146195ddebfec389877dfcef09bf8c23 /src/main/scala/scala/async/internal | |
parent | d7914c3879cbe832b640c07a24ee6941fa545928 (diff) | |
parent | e1377aa06ffe817d15315bbce3a6a636f2dd1f0e (diff) | |
download | scala-async-30cc2c51036bb0d1bc3c53ff600bfbe62a8be542.tar.gz scala-async-30cc2c51036bb0d1bc3c53ff600bfbe62a8be542.tar.bz2 scala-async-30cc2c51036bb0d1bc3c53ff600bfbe62a8be542.zip |
Merge pull request #115 from retronym/backport/74v0.9.4_2.10
Avoid compiler warning when awaiting Future[Unit]
Diffstat (limited to 'src/main/scala/scala/async/internal')
-rw-r--r-- | src/main/scala/scala/async/internal/AnfTransform.scala | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/main/scala/scala/async/internal/AnfTransform.scala b/src/main/scala/scala/async/internal/AnfTransform.scala index bf66fde..3c8c837 100644 --- a/src/main/scala/scala/async/internal/AnfTransform.scala +++ b/src/main/scala/scala/async/internal/AnfTransform.scala @@ -73,7 +73,17 @@ private[async] trait AnfTransform { expr match { case Apply(fun, args) if isAwait(fun) => val valDef = defineVal(name.await, expr, tree.pos) - stats :+ valDef :+ atPos(tree.pos)(gen.mkAttributedStableRef(valDef.symbol)).setType(tree.tpe) + val ref = gen.mkAttributedStableRef(valDef.symbol).setType(tree.tpe) + val ref1 = if (ref.tpe =:= definitions.UnitTpe) + // https://github.com/scala/async/issues/74 + // Use a cast to hide from "pure expression does nothing" error + // + // TODO avoid creating a ValDef for the result of this await to avoid this tree shape altogether. + // This will require some deeper changes to the later parts of the macro which currently assume regular + // tree structure around `await` calls. + gen.mkCast(ref, definitions.UnitTpe) + else ref + stats :+ valDef :+ atPos(tree.pos)(ref1) case If(cond, thenp, elsep) => // if type of if-else is Unit don't introduce assignment, |