makes boxity of fast track macros configurable

Previously, all built-in macros were assumed to be whitebox, but that’s
actually not the case. Just quasiquote macros have to be whitebox, while
the rest can be blackbox.

This also fixes SI-8091, because blackbox macros are typechecked differently
and therefore the necessary implicit conversion kicks in. If `f”...”` were
to remain a whitebox macro, then due to the changes introduced in commit
https://github.com/scala/scala/commit/a3b33419b02cafb7e2c6fed6dd96151859fc7d77
we would have to explicitly ascribe its expansion as String to achieve the same effect.

After I made reify blackbox, several tests had to be changed, because
we now explicitly ascribe the expansion with `c.Expr[T]`, which changes `toString`.
Also, a number of less obvious corrections had to be applied, because
things like `reify(<constant>).splice` have stopped being optimized away
due to `reify(<constant>)` no longer having a narrow `c.Expr[<constant>.type]`,
making it ineligible for constant folding.

Moreover, this change forced me to adjust our approach to positioning
blackbox wrappings, because after being changed to blacbox and starting using
wrappings, f”...” interpolators used in the compiler started crashing
-Yrangepos builds. Now wrapping Typed nodes are assigned with transparent
positions.

13 files changed, 34 insertions, 11 deletions

diff --git a/test/files/neg/compile-time-only-b.check b/test/files/neg/compile-time-only-b.check
index 8292a0ddeb..50cdf57fb5 100644
--- a/test/files/neg/compile-time-only-b.check
+++ b/test/files/neg/compile-time-only-b.check
@@ -1,7 +1,13 @@
+compile-time-only-b.scala:9: error: splice must be enclosed within a reify {} block
+  val ignored1 = expr.splice
+                      ^
+compile-time-only-b.scala:10: error: cannot use value except for signatures of macro implementations
+  val ignored2 = expr.value
+                      ^
 compile-time-only-b.scala:13: error: splice must be enclosed within a reify {} block
   val ignored3 = reify(fortyTwo).splice
                                  ^
 compile-time-only-b.scala:14: error: cannot use value except for signatures of macro implementations
   val ignored4 = reify(fortyTwo).value
                                  ^
-two errors found
+four errors found
diff --git a/test/files/neg/macro-reify-splice-splice.check b/test/files/neg/macro-reify-splice-splice.check
new file mode 100644
index 0000000000..bd1ea7acee
--- /dev/null
+++ b/test/files/neg/macro-reify-splice-splice.check
@@ -0,0 +1,7 @@
+Macros_1.scala:8: error: the splice cannot be resolved statically, which means there is a cross-stage evaluation involved.
+cross-stage evaluations need to be invoked explicitly, so we're showing you this error.
+if you're sure this is not an oversight, add scala-compiler.jar to the classpath,
+import `scala.tools.reflect.Eval` and call `<your expr>.eval` instead.
+      { c.universe.reify(c.universe.reify("hello world")) }.splice.splice
+                                                                   ^
+one error found
diff --git a/test/files/run/macro-reify-splice-splice.flags b/test/files/neg/macro-reify-splice-splice.flags
index cd66464f2f..cd66464f2f 100644
--- a/test/files/run/macro-reify-splice-splice.flags
+++ b/test/files/neg/macro-reify-splice-splice.flags
diff --git a/test/files/run/macro-reify-splice-splice/Macros_1.scala b/test/files/neg/macro-reify-splice-splice/Macros_1.scala
index 691f22ad07..691f22ad07 100644
--- a/test/files/run/macro-reify-splice-splice/Macros_1.scala
+++ b/test/files/neg/macro-reify-splice-splice/Macros_1.scala
diff --git a/test/files/run/macro-reify-splice-splice/Test_2.scala b/test/files/neg/macro-reify-splice-splice/Test_2.scala
index f697da6020..f697da6020 100644
--- a/test/files/run/macro-reify-splice-splice/Test_2.scala
+++ b/test/files/neg/macro-reify-splice-splice/Test_2.scala
diff --git a/test/files/neg/t6539.check b/test/files/neg/t6539.check
index b647636338..8c94a8ad4c 100644
--- a/test/files/neg/t6539.check
+++ b/test/files/neg/t6539.check
@@ -7,4 +7,10 @@ Test_2.scala:3: error: cto may only be used as an argument to m
 Test_2.scala:5: error: cto may only be used as an argument to m
   M.cto // error
     ^
-three errors found
+Test_2.scala:9: error: splice must be enclosed within a reify {} block
+    val splice = expr.splice
+                      ^
+Test_2.scala:10: error: cannot use value except for signatures of macro implementations
+    val value = expr.value
+                     ^
+5 errors found
diff --git a/test/files/run/macro-reify-splice-splice.check b/test/files/run/macro-reify-splice-splice.check
deleted file mode 100644
index 3b18e512db..0000000000
--- a/test/files/run/macro-reify-splice-splice.check
+++ /dev/null
@@ -1 +0,0 @@
-hello world
diff --git a/test/files/run/macro-typecheck-macrosdisabled.check b/test/files/run/macro-typecheck-macrosdisabled.check
index e0e880ab66..0579a4f4c8 100644
--- a/test/files/run/macro-typecheck-macrosdisabled.check
+++ b/test/files/run/macro-typecheck-macrosdisabled.check
@@ -1,4 +1,4 @@
-{
+({
   val $u: reflect.runtime.universe.type = scala.reflect.runtime.`package`.universe;
   val $m: $u.Mirror = scala.reflect.runtime.`package`.universe.runtimeMirror(this.getClass().getClassLoader());
   $u.Expr.apply[Int(2)]($m, {
@@ -28,5 +28,5 @@
     };
     new $typecreator2()
   }))
-}
+}: reflect.runtime.universe.Expr[Int])
 ru.reify[Int](2)
diff --git a/test/files/run/macro-typecheck-macrosdisabled2.check b/test/files/run/macro-typecheck-macrosdisabled2.check
index 347dfec1dc..c6e1c08d5d 100644
--- a/test/files/run/macro-typecheck-macrosdisabled2.check
+++ b/test/files/run/macro-typecheck-macrosdisabled2.check
@@ -1,4 +1,4 @@
-{
+({
   val $u: reflect.runtime.universe.type = scala.reflect.runtime.`package`.universe;
   val $m: $u.Mirror = scala.reflect.runtime.`package`.universe.runtimeMirror(this.getClass().getClassLoader());
   $u.Expr.apply[Array[Int]]($m, {
@@ -28,5 +28,5 @@
     };
     new $typecreator2()
   }))
-}
+}: reflect.runtime.universe.Expr[Array[Int]])
 ru.reify[Array[Int]](scala.Array.apply(2))
diff --git a/test/files/run/t8091.check b/test/files/run/t8091.check
new file mode 100644
index 0000000000..4c4e91774f
--- /dev/null
+++ b/test/files/run/t8091.check
@@ -0,0 +1 @@
+b&#x00f6;rk b&#x00f6;rk
diff --git a/test/files/run/t8091.scala b/test/files/run/t8091.scala
new file mode 100644
index 0000000000..cd412d4c2a
--- /dev/null
+++ b/test/files/run/t8091.scala
@@ -0,0 +1,4 @@
+object Test extends App {
+  val result = "börk börk" flatMap (ch ⇒ if (ch > 127) f"&#x${ch}%04x;" else "" + ch)
+  println(result)
+}
\ No newline at end of file
diff --git a/test/files/run/toolbox_typecheck_macrosdisabled.check b/test/files/run/toolbox_typecheck_macrosdisabled.check
index 3de296f1ad..d9e79cdd19 100644
--- a/test/files/run/toolbox_typecheck_macrosdisabled.check
+++ b/test/files/run/toolbox_typecheck_macrosdisabled.check
@@ -1,4 +1,4 @@
-{
+({
   val $u: ru.type = ru;
   val $m: $u.Mirror = ru.runtimeMirror({
   final class $anon extends scala.AnyRef {
@@ -37,5 +37,5 @@
     };
     new $typecreator2()
   }))
-}
+}: ru.Expr[Int])
 ru.reify[Int](2)
diff --git a/test/files/run/toolbox_typecheck_macrosdisabled2.check b/test/files/run/toolbox_typecheck_macrosdisabled2.check
index 9810946024..8e554a6c8f 100644
--- a/test/files/run/toolbox_typecheck_macrosdisabled2.check
+++ b/test/files/run/toolbox_typecheck_macrosdisabled2.check
@@ -1,4 +1,4 @@
-{
+({
   val $u: ru.type = ru;
   val $m: $u.Mirror = ru.runtimeMirror({
   final class $anon extends scala.AnyRef {
@@ -37,5 +37,5 @@
     };
     new $typecreator2()
   }))
-}
+}: ru.Expr[Array[Int]])
 ru.reify[Array[Int]](scala.Array.apply(2))