SI-9630 Fix spurious warning related to same-named case accessors

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.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala b/src/compiler/scala/tools/nsc/transform/patmat/Logic.scala
index 1a4df9973e..8b2e09495f 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