SI-8366 make partial function and match trees disjoint

Previously one could match a partial function with match quasiquote:

    scala> val q"$scrutinee match { case ..$cases }" = q"{ case Foo => Bar
    }"
    scrutinee: universe.Tree = <empty>
    cases: List[universe.CaseDef] = List(case Foo => Bar)

This was quite annoying as it leaked encoding of partial functions as
Match trees with empty tree in place of scrutinee.

This commit make sure that matches and partial functions are disjoint
and don't match one another (while preserving original encoding under
the hood out of sight of the end user.)

1 files changed, 5 insertions, 0 deletions

diff --git a/bincompat-backward.whitelist.conf b/bincompat-backward.whitelist.conf
index e82c0fd16d..ae31c286f3 100644
--- a/bincompat-backward.whitelist.conf
+++ b/bincompat-backward.whitelist.conf
@@ -122,6 +122,11 @@ filter {
     {
         matchName="scala.reflect.api.Internals#ReificationSupportApi.SyntacticSelectTerm"
         problemName=MissingMethodProblem
+    },
+    // see SI-8366
+    {
+        matchName="scala.reflect.api.Internals#ReificationSupportApi.SyntacticPartialFunction"
+        problemName=MissingMethodProblem
     }
   ]
 }