Merge pull request #8205 from dotty-staging/fix-#7142-2

Fix #7142: Detect escaped variables across macro expansion

Author: nicolasstucki

community-build/community-projects/sourcecode

@@ -41,7 +41,7 @@ object Splicer {
     case Quoted(quotedTree) => quotedTree
     case _ =>
       val interpreter = new Interpreter(pos, classLoader)
-      val macroOwner = ctx.newSymbol(ctx.owner, NameKinds.UniqueName.fresh(nme.MACROkw), Synthetic, defn.AnyType, coord = tree.span)
+      val macroOwner = ctx.newSymbol(ctx.owner, nme.MACROkw, Macro | Synthetic, defn.AnyType, coord = tree.span)
       try {
         given Context = ctx.withOwner(macroOwner)
         // Some parts of the macro are evaluated during the unpickling performed in quotedExprToTree
@@ -100,7 +100,10 @@ object Splicer {
             traverseChildren(tree)
       private def isEscapedVariable(sym: Symbol)(given ctx: Context): Boolean =
         sym.exists && !sym.is(Package)
-        && sym.owner.ownersIterator.contains(expansionOwner) // symbol was generated within the macro expansion
+        && sym.owner.ownersIterator.exists(x =>
+          x == expansionOwner || // symbol was generated within this macro expansion
+          x.is(Macro, butNot = Method) && x.name == nme.MACROkw // symbol was generated within another macro expansion
+        )
         && !locals.contains(sym) // symbol is not in current scope
     }.traverse(tree)
     tree

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

@@ -0,0 +1,11 @@
+package macros
+import scala.quoted._
+
+var saved = Option.empty[Expr[Int]]
+
+def oops(given QuoteContext) = {
+  if (saved.isEmpty) '{ (x: Int) => ${ saved = Some('{x}); 'x } }
+  else saved.get
+}
+
+inline def test = ${oops}

tests/neg-macros/i7142h/Macro_1.scala

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

tests/neg-macros/i7142h/Test_2.scala

@@ -1,5 +1,5 @@
 foo
-ValDef("macro$1", Inferred(), None)
+ValDef("macro", Inferred(), None)
 
 bar
 DefDef("foo", Nil, Nil, Inferred(), None)
@@ -8,7 +8,7 @@ bar2
 DefDef("foo", Nil, Nil, Inferred(), None)
 
 foo2
-ValDef("macro$1", Inferred(), None)
+ValDef("macro", Inferred(), None)
 
 baz
 ValDef("foo2", Inferred(), None)

tests/run-custom-args/Yretain-trees/tasty-extractors-owners.check

@@ -1,6 +1,6 @@
-foo Location(List(Test$, loc1, macro$1))
-foo Location(List(Test$, main, macro$2))
-foo Location(List(Test$, main, macro$3))
-foo Location(List(Test$, main, bar, macro$4))
-foo Location(List(Test$, main, bar, baz, macro$5))
-foo Location(List(Test$, main, f, $anonfun, macro$6))
+foo Location(List(Test$, loc1, macro))
+foo Location(List(Test$, main, macro))
+foo Location(List(Test$, main, macro))
+foo Location(List(Test$, main, bar, macro))
+foo Location(List(Test$, main, bar, baz, macro))
+foo Location(List(Test$, main, f, $anonfun, macro))