Merge pull request #14871 from dotty-staging/fix-8967

Don't issue unreachable error messages for inlined code

Author: odersky

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))

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"
 

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] = ???
+}

tests/neg/i6371/B_2.scala renamed to tests/neg-macros/i6371/B_2.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")