From e88eb5b55d7734c91b827c774b9e9a162ad4d3f0 Mon Sep 17 00:00:00 2001
From: odersky <odersky@gmail.com>
Date: Thu, 7 Apr 2022 12:02:47 +0200
Subject: [PATCH 1/2] Don't issue unreachable error messages for inlined code

Fixes #8967
---
 .../src/dotty/tools/dotc/transform/TypeTestsCasts.scala     | 3 ++-
 tests/pos/i8967.scala                                       | 6 ++++++
 2 files changed, 8 insertions(+), 1 deletion(-)
 create mode 100644 tests/pos/i8967.scala

diff --git a/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala b/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
index 371982a8b442..c2367e6bfde0 100644
--- a/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
+++ b/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
@@ -354,7 +354,8 @@ object TypeTestsCasts {
           val isTrusted = tree.hasAttachment(PatternMatcher.TrustedTypeTestKey)
           if (!isTrusted && !checkable(expr.tpe, argType, tree.span))
             report.uncheckedWarning(i"the type test for $argType cannot be checked at runtime", expr.srcPos)
-          transformTypeTest(expr, tree.args.head.tpe, flagUnrelated = true)
+          transformTypeTest(expr, tree.args.head.tpe,
+            flagUnrelated = enclosingInlineds.isEmpty) // if test comes from inlined code, dont't flag it even if it always false
         }
         else if (sym.isTypeCast)
           transformAsInstanceOf(erasure(tree.args.head.tpe))
diff --git a/tests/pos/i8967.scala b/tests/pos/i8967.scala
new file mode 100644
index 000000000000..8b612118621c
--- /dev/null
+++ b/tests/pos/i8967.scala
@@ -0,0 +1,6 @@
+inline def aToB[T,A,B](t:T,b:B): T|B = t match {
+  case _:A => b
+  case _:T => t
+}
+
+@main def main() = aToB[Int, Double, String](1,"x")

From f0012e930ce0ccabce0530c4233c27d555a1b2ac Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Fri, 8 Apr 2022 11:02:12 +0200
Subject: [PATCH 2/2] Update test for #6371

---
 project/scripts/cmdTests                  | 6 +++---
 tests/neg-macros/i6371/A_1.scala          | 5 +++++
 tests/{neg => neg-macros}/i6371/B_2.scala | 0
 tests/neg/i6371/A_1.scala                 | 6 ------
 4 files changed, 8 insertions(+), 9 deletions(-)
 create mode 100644 tests/neg-macros/i6371/A_1.scala
 rename tests/{neg => neg-macros}/i6371/B_2.scala (100%)
 delete mode 100644 tests/neg/i6371/A_1.scala

diff --git a/project/scripts/cmdTests b/project/scripts/cmdTests
index 6a175db23e99..3405c06b056f 100755
--- a/project/scripts/cmdTests
+++ b/project/scripts/cmdTests
@@ -51,12 +51,12 @@ fi
 echo "testing that missing source file does not crash message rendering"
 clear_out "$OUT"
 clear_out "$OUT1"
-cp tests/neg/i6371/A_1.scala $OUT/A.scala
-cp tests/neg/i6371/B_2.scala $OUT/B.scala
+cp tests/neg-macros/i6371/A_1.scala $OUT/A.scala
+cp tests/neg-macros/i6371/B_2.scala $OUT/B.scala
 "$SBT" "scalac $OUT/A.scala -d $OUT1"
 rm $OUT/A.scala
 "$SBT" "scalac -classpath $OUT1 -d $OUT1 $OUT/B.scala" > "$tmp" 2>&1 || echo "ok"
-cat "$tmp" # for debugging
+# cat "$tmp" # for debugging
 grep -qe "B.scala:2:7" "$tmp"
 grep -qe "This location contains code that was inlined from A.scala:3" "$tmp"
 
diff --git a/tests/neg-macros/i6371/A_1.scala b/tests/neg-macros/i6371/A_1.scala
new file mode 100644
index 000000000000..bf94545c595e
--- /dev/null
+++ b/tests/neg-macros/i6371/A_1.scala
@@ -0,0 +1,5 @@
+import scala.quoted.*
+object A {
+  inline def foo(a: Any): Unit = ${ crashOnInline }
+  def crashOnInline(using Quotes): Expr[Unit] = ???
+}
diff --git a/tests/neg/i6371/B_2.scala b/tests/neg-macros/i6371/B_2.scala
similarity index 100%
rename from tests/neg/i6371/B_2.scala
rename to tests/neg-macros/i6371/B_2.scala
diff --git a/tests/neg/i6371/A_1.scala b/tests/neg/i6371/A_1.scala
deleted file mode 100644
index 186ee85f6ed4..000000000000
--- a/tests/neg/i6371/A_1.scala
+++ /dev/null
@@ -1,6 +0,0 @@
-object A {
-  inline def foo(a: Any): Unit = a match {
-    case _: Int =>
-    case _ =>
-  }
-}