From dd2a5d0e158f83302354cdf56ad587d0c1258258 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Fri, 18 Dec 2020 10:45:56 +0100
Subject: [PATCH] Fix #10127: Don't try to get tags after error

The tags may be unavailablle due to the error.
---
 .../dotty/tools/dotc/transform/PCPCheckAndHeal.scala   |  7 +++++--
 tests/neg-macros/i10127-a.scala                        |  8 ++++++++
 tests/neg-macros/i10127-b.scala                        | 10 ++++++++++
 tests/pos-macros/i10127.scala                          |  8 ++++++++
 4 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 tests/neg-macros/i10127-a.scala
 create mode 100644 tests/neg-macros/i10127-b.scala
 create mode 100644 tests/pos-macros/i10127.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala b/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala
index 724971d869f8..15d76b88a13f 100644
--- a/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala
+++ b/compiler/src/dotty/tools/dotc/transform/PCPCheckAndHeal.scala
@@ -140,8 +140,11 @@ class PCPCheckAndHeal(@constructorOnly ictx: Context) extends TreeMapWithStages(
 
   protected def transformSpliceType(body: Tree, splice: Select)(using Context): Tree = {
     val body1 = transform(body)(using spliceContext)
-    val tagRef = getQuoteTypeTags.getTagRef(splice.qualifier.tpe.asInstanceOf[TermRef])
-    ref(tagRef).withSpan(splice.span)
+    if ctx.reporter.hasErrors then
+      splice
+    else
+      val tagRef = getQuoteTypeTags.getTagRef(splice.qualifier.tpe.asInstanceOf[TermRef])
+      ref(tagRef).withSpan(splice.span)
   }
 
   /** Check that annotations do not contain quotes and and that splices are valid */
diff --git a/tests/neg-macros/i10127-a.scala b/tests/neg-macros/i10127-a.scala
new file mode 100644
index 000000000000..c62dab8b7ac2
--- /dev/null
+++ b/tests/neg-macros/i10127-a.scala
@@ -0,0 +1,8 @@
+import scala.quoted._
+
+object T {
+  def impl[A](using t: Type[A])(using Quotes): Expr[Unit] = {
+    Expr.summon[t.Underlying] // error
+    '{}
+  }
+}
\ No newline at end of file
diff --git a/tests/neg-macros/i10127-b.scala b/tests/neg-macros/i10127-b.scala
new file mode 100644
index 000000000000..8c69ea5444c1
--- /dev/null
+++ b/tests/neg-macros/i10127-b.scala
@@ -0,0 +1,10 @@
+import scala.quoted._
+
+case class T(x: Type[_ <: Any])
+
+object T {
+  def impl[A](t: T)(using ctx: Quotes): Expr[Unit] = {
+    Expr.summon[t.x.Underlying] // error // error
+    '{}
+  }
+}
\ No newline at end of file
diff --git a/tests/pos-macros/i10127.scala b/tests/pos-macros/i10127.scala
new file mode 100644
index 000000000000..ccd710728d21
--- /dev/null
+++ b/tests/pos-macros/i10127.scala
@@ -0,0 +1,8 @@
+import scala.quoted._
+
+object T {
+  def impl[A](using Type[A])(using Quotes): Expr[Unit] = {
+    Expr.summon[A]
+    '{}
+  }
+}
\ No newline at end of file