Assert that memberType selects an existing memberType

Fixes #15159
Updates buggy tests of #13230

Author: nicolasstucki

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

@@ -1779,6 +1779,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
         def termSymbol: Symbol = self.termSymbol
         def isSingleton: Boolean = self.isSingleton
         def memberType(member: Symbol): TypeRepr =
+          assert(self.derivesFrom(member.owner), s"$member is not a member of ${self.show}")
           member.info.asSeenFrom(self, member.owner)
         def baseClasses: List[Symbol] = self.baseClasses
         def baseType(cls: Symbol): TypeRepr = self.baseType(cls)

tests/neg-macros/i15159/Macro_1.scala

@@ -0,0 +1,10 @@
+import scala.quoted.*
+object TestMacro:
+  inline def test[T]: Unit = ${ testImpl[T] }
+  def testImpl[T: Type](using Quotes): Expr[Unit] =
+    import quotes.reflect.*
+    val tpe = TypeRepr.of[T]
+    tpe.typeSymbol.children.map { childSymbol =>
+      tpe.memberType(childSymbol) // not a member of tpe
+    }
+    '{ () }

tests/neg-macros/i15159/Test_2.scala

@@ -0,0 +1,6 @@
+sealed trait A
+case class X(i: Int) extends A
+
+object Test extends App {
+  TestMacro.test[A] // error
+}

tests/run-macros/i13230/Macros_1.scala

@@ -7,6 +7,6 @@ inline def showEnumChildren = ${ showEnumChildrenExpr }
 
 def showEnumChildrenExpr(using Quotes) =
   import quotes.reflect.*
-  val repr = TypeRepr.of[E]
+  val repr = TypeRepr.of[E.type] // we know that all the implementations of the class E are in the object E
   Expr(TypeRepr.of[E].classSymbol.get.children.map(sym => (sym.name, repr.memberType(sym).show)))