From 311e1a4cfbcae6cab95401aac8faa07fe8381ff9 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Tue, 23 Apr 2019 17:04:51 +0200
Subject: [PATCH] Avoid crashes when spliced tree does not have an Expr[T] type

---
 compiler/src/dotty/tools/dotc/ast/tpd.scala | 8 ++++++--
 tests/neg/quotedPatterns-4.scala            | 9 +++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)
 create mode 100644 tests/neg/quotedPatterns-4.scala

diff --git a/compiler/src/dotty/tools/dotc/ast/tpd.scala b/compiler/src/dotty/tools/dotc/ast/tpd.scala
index ca505ef69529..28f11a24de21 100644
--- a/compiler/src/dotty/tools/dotc/ast/tpd.scala
+++ b/compiler/src/dotty/tools/dotc/ast/tpd.scala
@@ -1181,9 +1181,13 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   /** An extractor for typed splices */
   object Splice {
     def apply(tree: Tree)(implicit ctx: Context): Tree = {
+      val baseType = tree.tpe.baseType(defn.QuotedExprClass)
       val argType =
-        if (tree.tpe.widen.isError) tree.tpe.widen
-        else tree.tpe.baseType(defn.QuotedExprClass).argTypesHi.head
+        if (baseType != NoType) baseType.argTypesHi.head
+        else {
+          assert(ctx.reporter.hasErrors)
+          defn.NothingType
+        }
       ref(defn.InternalQuoted_exprSplice).appliedToType(argType).appliedTo(tree)
     }
     def unapply(tree: Tree)(implicit ctx: Context): Option[Tree] = tree match {
diff --git a/tests/neg/quotedPatterns-4.scala b/tests/neg/quotedPatterns-4.scala
new file mode 100644
index 000000000000..d1fae244c94d
--- /dev/null
+++ b/tests/neg/quotedPatterns-4.scala
@@ -0,0 +1,9 @@
+import scala.quoted._
+object Test {
+  def impl(receiver: Expr[StringContext])(implicit reflect: scala.tasty.Reflection) = {
+    import reflect.Repeated
+    receiver match {
+      case '{ StringContext(${Repeated(parts)}: _*) } => // error
+    }
+  }
+}