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Diffstat (limited to 'src/compiler/scala/reflect/internal/Trees.scala')
| -rw-r--r-- | src/compiler/scala/reflect/internal/Trees.scala | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/compiler/scala/reflect/internal/Trees.scala b/src/compiler/scala/reflect/internal/Trees.scala index 9b1712b790..1a40e0105c 100644 --- a/src/compiler/scala/reflect/internal/Trees.scala +++ b/src/compiler/scala/reflect/internal/Trees.scala @@ -350,8 +350,9 @@ trait Trees extends api.Trees { self: SymbolTable => "subst[%s, %s](%s)".format(fromStr, toStr, (from, to).zipped map (_ + " -> " + _) mkString ", ") } - // NOTE: if symbols in `from` occur multiple times in the `tree` passed to `transform`, - // the resulting Tree will be a graph, not a tree... this breaks all sorts of stuff, + // NOTE: calls shallowDuplicate on trees in `to` to avoid problems when symbols in `from` + // occur multiple times in the `tree` passed to `transform`, + // otherwise, the resulting Tree would be a graph, not a tree... this breaks all sorts of stuff, // notably concerning the mutable aspects of Trees (such as setting their .tpe) class TreeSubstituter(from: List[Symbol], to: List[Tree]) extends Transformer { override def transform(tree: Tree): Tree = tree match { |