From 555eed406f77f68762a4243ed59fa48d94252c85 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Tue, 2 Jul 2019 15:17:14 +0200
Subject: [PATCH] Fix #6679: Handle wildcards in PCP check

---
 .../tools/dotc/transform/PCPCheckAndHeal.scala     | 12 ++++++++----
 tests/run-macros/i6679.check                       |  1 +
 tests/run-macros/i6679/Macro_1.scala               | 14 ++++++++++++++
 tests/run-macros/i6679/Test_2.scala                |  8 ++++++++
 4 files changed, 31 insertions(+), 4 deletions(-)
 create mode 100644 tests/run-macros/i6679.check
 create mode 100644 tests/run-macros/i6679/Macro_1.scala
 create mode 100644 tests/run-macros/i6679/Test_2.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala b/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala
index 342b8f844fe5..c9c96635d7c1 100644
--- a/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala
+++ b/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala
@@ -98,10 +98,14 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages(
       case _: This =>
         assert(checkSymLevel(tree.symbol, tree.tpe, tree.sourcePos).isEmpty)
         tree
-      case _: Ident =>
-        checkSymLevel(tree.symbol, tree.tpe, tree.sourcePos) match {
-          case Some(tpRef) => tpRef
-          case _ => tree
+      case Ident(name) =>
+        if (name == nme.WILDCARD) {
+          untpd.Ident(name).withType(checkType(tree.sourcePos).apply(tree.tpe)).withSpan(tree.span)
+        } else {
+          checkSymLevel(tree.symbol, tree.tpe, tree.sourcePos) match {
+            case Some(tpRef) => tpRef
+            case _ => tree
+          }
         }
       case _: TypeTree | _: AppliedTypeTree | _: Apply | _: TypeApply | _: UnApply | Select(_, OuterSelectName(_, _)) =>
         tree.withType(checkTp(tree.tpe))
diff --git a/tests/run-macros/i6679.check b/tests/run-macros/i6679.check
new file mode 100644
index 000000000000..7326d9603970
--- /dev/null
+++ b/tests/run-macros/i6679.check
@@ -0,0 +1 @@
+Ok
diff --git a/tests/run-macros/i6679/Macro_1.scala b/tests/run-macros/i6679/Macro_1.scala
new file mode 100644
index 000000000000..74087d709d1f
--- /dev/null
+++ b/tests/run-macros/i6679/Macro_1.scala
@@ -0,0 +1,14 @@
+import scala.quoted._
+
+def makeMatch[A: Type](head : Expr[A]) given (qctx : QuoteContext) : Expr[Unit] = {
+  import qctx.tasty._
+
+  val sacrifice = '{ $head match { case _ => ??? } }
+  sacrifice.unseal
+
+  '{ println("Ok") }
+}
+
+def mm(implicit qctx : QuoteContext) = makeMatch('{42})
+
+inline def f = ${ mm }
diff --git a/tests/run-macros/i6679/Test_2.scala b/tests/run-macros/i6679/Test_2.scala
new file mode 100644
index 000000000000..89e8042dbbbf
--- /dev/null
+++ b/tests/run-macros/i6679/Test_2.scala
@@ -0,0 +1,8 @@
+import scala.quoted._
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    f
+  }
+}
\ No newline at end of file