Merge pull request #14425 from dwijnand/quote-matching-avoidance

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -3056,8 +3056,9 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
       // that we have found, seal them in a quoted.Type and add them to the result
       def typeHoleApproximation(sym: Symbol) =
         val fromAboveAnnot = sym.hasAnnotation(dotc.core.Symbols.defn.QuotedRuntimePatterns_fromAboveAnnot)
-        val approx = ctx1.gadt.approximation(sym, !fromAboveAnnot)
-        reflect.TypeReprMethods.asType(approx)
+        val fullBounds = ctx1.gadt.fullBounds(sym)
+        val tp = if fromAboveAnnot then fullBounds.hi else fullBounds.lo
+        reflect.TypeReprMethods.asType(tp)
       matchings.map { tup =>
         Tuple.fromIArray(typeHoles.map(typeHoleApproximation).toArray.asInstanceOf[IArray[Object]]) ++ tup
       }

tests/pos-macros/i12343/Macro.scala

@@ -0,0 +1,13 @@
+package test
+
+import scala.quoted.*
+
+object Macro:
+  def covImpl(arg: Expr[Any])(using Quotes): Expr[Any] = arg match // Covariant (List)
+    case '{ $h : List[h] } => '{ $h : List[h] }
+
+  def invImpl(arg: Expr[Any])(using Quotes): Expr[Any] = arg match // Invariant (Set)
+    case '{ $h : Set[h] } => '{ $h : Set[h] }
+
+  transparent inline def cov(inline arg: Any): Any = ${ covImpl('arg) }
+  transparent inline def inv(inline arg: Any): Any = ${ invImpl('arg) }

tests/pos-macros/i12343/Test.scala

@@ -0,0 +1,7 @@
+package test
+
+object Test:
+  val cov1: List[Boolean]          = Macro.cov(List(true))
+  val inv1: Set[Boolean]           = Macro.inv(Set(true))
+  def cov2[X](a: List[X]): List[X] = Macro.cov(a)
+  def inv2[X](a: Set[X]): Set[X]   = Macro.inv(a) // doesn't compile; Set[Nothing] is inferred