Merge pull request #6364 from dotty-staging/fix-crash-after-error-reported

Avoid crashes when spliced tree does not have an Expr[T] type

Author: nicolasstucki

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 {

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
+    }
+  }
+}