Handle $asInstanceOf$ in Splicer

Before that commit macro expansion would fail with:

"Could not find method Box$.$asInstanceOf$ with parameters (). The most common reason for that is that you apply macros in the compilation run that defines them"

Author: OlivierBlanvillain

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

@@ -264,9 +264,12 @@ object Splicer {
       }
 
       val name = getDirectName(fn.info.finalResultType, fn.name.asTermName)
-      val method = getMethod(clazz, name, paramsSig(fn))
-
-      (args: List[Object]) => stopIfRuntimeException(method.invoke(inst, args: _*))
+      if (name == nme.asInstanceOfPM)
+        (args: List[Object]) => interpretModuleAccess(moduleClass)
+      else {
+        val method = getMethod(clazz, name, paramsSig(fn))
+        (args: List[Object]) => stopIfRuntimeException(method.invoke(inst, args: _*))
+      }
     }
 
     private def interpretModuleAccess(fn: Symbol)(implicit env: Env): Object =

tests/run-macros/dollar-asInstanceOf-dollar/1.scala

@@ -0,0 +1,12 @@
+import scala.quoted._
+import scala.deriving._
+
+case class Box[A](x: A)
+
+object Macro {
+  inline def foo[X[_]](implicit inline m: Mirror { type MirroredType = X }): Int =
+    ${ fooImpl }
+
+  def fooImpl[X[_]](implicit m: Mirror { type MirroredType = X }, qc: QuoteContext): Expr[Int] =
+    '{ 1 }
+}

tests/run-macros/dollar-asInstanceOf-dollar/2.scala

@@ -0,0 +1,4 @@
+object Test {
+  def main(args: Array[String]): Unit =
+    assert(Macro.foo[Box] == 1)
+}