Fix scala#7142: Detect scope extrusions in macros and run

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -44,7 +44,9 @@ object Splicer {
       try {
         // Some parts of the macro are evaluated during the unpickling performed in quotedExprToTree
         val interpretedExpr = interpreter.interpret[scala.quoted.QuoteContext => scala.quoted.Expr[Any]](tree)
-        interpretedExpr.fold(tree)(macroClosure => PickledQuotes.quotedExprToTree(macroClosure(QuoteContext())))
+        val interpretedTree = interpretedExpr.fold(tree)(macroClosure => PickledQuotes.quotedExprToTree(macroClosure(QuoteContext())))
+        checkFreeVariables(interpretedTree)
+        interpretedTree
       }
       catch {
         case ex: CompilationUnit.SuspendException =>
@@ -63,6 +65,38 @@ object Splicer {
       }
   }
 
+  def checkFreeVariables(tree: Tree)(given ctx: Context): Unit =
+    println()
+    println(tree.show)
+    println(tree)
+    println(freeVariables(tree))
+    println()
+    println(tree.symbol.exists)
+    println(!tree.symbol.is(Package))
+    println(!tree.symbol.owner.isStaticOwner)
+    println(!ctx.owner.ownersIterator.contains(tree.symbol.owner))
+    println()
+    println(ctx.owner.ownersIterator.toList)
+    println(tree.symbol)
+    println(tree.symbol.owner)
+    println(tree.symbol.owner.isLocalDummy)
+    println(tree.symbol.owner.is(Local))
+    println()
+    println()
+    freeVariables(tree).foreach(x => ctx.error(em"$x was used outside the scope where it was defined", x.symbol.sourcePos))
+
+  private def freeVariables(tree: Tree)(given ctx: Context): List[Tree] =
+    def isFreeVariable(sym: Symbol): Boolean =
+      sym.exists && !sym.is(Package) && !sym.owner.isStaticOwner && !ctx.owner.ownersIterator.contains(sym.owner)
+    new TreeAccumulator[List[Tree]] {
+      private[this] val local = collection.mutable.HashSet.empty[Symbol]
+      def apply(x: List[Tree], tree: Tree)(given ctx: Context): List[Tree] = tree match {
+        case tree: Ident if local(tree.symbol) => tree :: x
+        case _ => foldOver(x, tree)
+      }
+    }.apply(Nil, tree)
+
+
   /** Check that the Tree can be spliced. `${'{xyz}}` becomes `xyz`
     *  and for `$xyz` the tree of `xyz` is interpreted for which the
     *  resulting expression is returned as a `Tree`

staging/src/scala/quoted/staging/QuoteCompiler.scala

@@ -68,6 +68,8 @@ private class QuoteCompiler extends Compiler {
           val qctx = dotty.tools.dotc.quoted.QuoteContext()
           val quoted = PickledQuotes.quotedExprToTree(exprUnit.exprBuilder.apply(qctx))(ctx.withOwner(meth))
 
+          dotty.tools.dotc.transform.Splicer.checkFreeVariables(quoted)
+
           getLiteral(quoted) match {
             case Some(value) =>
               result = Right(value)

tests/neg-macros/i7142/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ (x: Int) => ${ v = '{x}; v } } // error
+  '{$q($v)}
+}
+inline def test = ${oops}

tests/neg-macros/i7142/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142b/Macro_1.scala

@@ -0,0 +1,8 @@
+package macros
+import scala.quoted._
+import scala.util.control.NonLocalReturns._
+
+def oops(given QuoteContext): Expr[Int] =
+  returning('{ { (x: Int) => ${ throwReturn('x) }} apply 0 }) // error
+
+inline def test = ${oops}

tests/neg-macros/i7142b/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142c/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ val x: Int = 8; ${ v = '{x}; v } } // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142c/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142d/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ ??? match { case x => ${ v = '{x}; v } } } // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142d/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142e/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ def x: Int = 8; ${ v = '{x}; v } } // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142e/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142f/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ def f(x: Int): Int = ${ v = '{x}; v } } // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142f/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142g/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ class Foo(x: Int) { ${ v = 'x; '{} }  }} // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142g/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142i/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{0};
+  val q = '{ class Foo { val x = 3; ${ v = 'x; '{} }  }} // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142i/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/neg-macros/i7142j/Macro_1.scala

@@ -0,0 +1,9 @@
+package macros
+import scala.quoted._
+
+def oops(given QuoteContext) = {
+  var v = '{};
+  val q = '{ var x: Int = 8; ${ v = '{x = 9}; v } } // error
+  v
+}
+inline def test = ${oops}

tests/neg-macros/i7142j/Test_2.scala

@@ -0,0 +1,4 @@
+
+object Test {
+  macros.test
+}

tests/run-staging/i7142.scala

@@ -0,0 +1,12 @@
+import scala.quoted._
+import scala.quoted.staging._
+import scala.util.control.NonLocalReturns._
+
+object Test {
+  given Toolbox = Toolbox.make(getClass.getClassLoader)
+  def main(args: Array[String]): Unit =
+    try run {returning('{ { (x: Int) => ${ throwReturn('x) }} apply 0 })}
+    catch {
+      case ex: dotty.tools.dotc.reporting.diagnostic.messages.Error if ex.getMessage == "x was used outside the scope where it was defined" => // OK
+    }
+}