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author | Jason Zaugg <jzaugg@gmail.com> | 2016-01-27 19:01:25 +1000 |
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committer | Adriaan Moors <adriaan@lightbend.com> | 2016-12-21 16:53:28 -0800 |
commit | da986839d17dbbd41877df809e3efed8d63deb4e (patch) | |
tree | e198a85516c67b8381ac1f45e64e4cb26daa6bb7 /src/compiler/scala/tools/nsc | |
parent | 80ce23103ca72762ced87e5cb97e8ae34b434edd (diff) | |
download | scala-da986839d17dbbd41877df809e3efed8d63deb4e.tar.gz scala-da986839d17dbbd41877df809e3efed8d63deb4e.tar.bz2 scala-da986839d17dbbd41877df809e3efed8d63deb4e.zip |
SI-9630 Fix spurious warning related to same-named case accessors [backport]
Hash consing of trees within pattern match analysis was broken, and
considered `x1.foo#1` to be the same tree as `x1.foo#2`, even though
the two `foo`-s referred to different symbols.
The hash consing was based on `Tree#correspondsStructure`, but the
predicate in that function cannot veto correspondance, it can only
supplement the default structural comparison.
I've instead created a custom tree comparison method for use in
the pattern matcher that handles the tree shapes that we use.
(cherry picked from commit 79a52e6807d2797dee12bab1730765441a0e222d)
Diffstat (limited to 'src/compiler/scala/tools/nsc')
-rw-r--r-- | src/compiler/scala/tools/nsc/transform/patmat/Logic.scala | 2 | ||||
-rw-r--r-- | src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala | 16 |
2 files changed, 11 insertions, 7 deletions
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala b/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala index 91777b34d5..40fcceb0bf 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala @@ -691,7 +691,7 @@ trait ScalaLogic extends Interface with Logic with TreeAndTypeAnalysis { // if X is mutable. freshExistentialSubtype(t.tpe) } - else trees find (a => a.correspondsStructure(t)(sameValue)) match { + else trees find (a => equivalentTree(a, t)) match { case Some(orig) => debug.patmat("unique tp for tree: " + ((orig, orig.tpe))) orig.tpe diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala index 1331eb6993..c71299b893 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala @@ -85,11 +85,15 @@ trait TreeAndTypeAnalysis extends Debugging { tp <:< tpImpliedNormalizedToAny } - // TODO: improve, e.g., for constants - def sameValue(a: Tree, b: Tree): Boolean = (a eq b) || ((a, b) match { - case (_ : Ident, _ : Ident) => a.symbol eq b.symbol - case _ => false - }) + def equivalentTree(a: Tree, b: Tree): Boolean = (a, b) match { + case (Select(qual1, _), Select(qual2, _)) => equivalentTree(qual1, qual2) && a.symbol == b.symbol + case (Ident(_), Ident(_)) => a.symbol == b.symbol + case (Literal(c1), Literal(c2)) => c1 == c2 + case (This(_), This(_)) => a.symbol == b.symbol + case (Apply(fun1, args1), Apply(fun2, args2)) => equivalentTree(fun1, fun2) && args1.corresponds(args2)(equivalentTree) + // Those are the only cases we need to handle in the pattern matcher + case _ => false + } trait CheckableTreeAndTypeAnalysis { val typer: Typer @@ -277,7 +281,7 @@ trait MatchApproximation extends TreeAndTypeAnalysis with ScalaLogic with MatchT // hashconsing trees (modulo value-equality) def unique(t: Tree, tpOverride: Type = NoType): Tree = - trees find (a => a.correspondsStructure(t)(sameValue)) match { + trees find (a => equivalentTree(a, t)) match { case Some(orig) => // debug.patmat("unique: "+ (t eq orig, orig)) orig |