Handle SummonFrom in reflect TreeAccumulator

Fixes #14789

Author: nicolasstucki

library/src/scala/quoted/Quotes.scala

@@ -4621,6 +4621,7 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
           case Bind(_, body) => foldTree(x, body)(owner)
           case Unapply(fun, implicits, patterns) => foldTrees(foldTrees(foldTree(x, fun)(owner), implicits)(owner), patterns)(owner)
           case Alternatives(patterns) => foldTrees(x, patterns)(owner)
+          case SummonFrom(cases) => foldTrees(x, cases)(owner)
           case _ => throw MatchError(tree.show(using Printer.TreeStructure))
         }
       }

tests/run-custom-args/tasty-inspector/i14789.scala

@@ -0,0 +1,43 @@
+import scala.quoted.*
+import scala.tasty.inspector.*
+
+@main def Test = {
+  // Artefact of the current test infrastructure
+  // TODO improve infrastructure to avoid needing this code on each test
+  val classpath = dotty.tools.dotc.util.ClasspathFromClassloader(this.getClass.getClassLoader).split(java.io.File.pathSeparator).find(_.contains("runWithCompiler")).get
+  val allTastyFiles = dotty.tools.io.Path(classpath).walkFilter(_.extension == "tasty").map(_.toString).toList
+  val tastyFiles = allTastyFiles.filter(_.contains("App"))
+
+  // in dotty-example-project
+  val inspector = new Inspector {
+    def inspect(using Quotes)(tastys: List[Tasty[quotes.type]]): Unit = {
+      import quotes.reflect.*
+      val traverser = new TreeTraverser {
+        override def traverseTree(tree: Tree)(owner: Symbol): Unit = {
+          try {
+            super.traverseTree(tree)(owner)
+          } catch {
+            case e =>
+              report.error(s"unexpected error ${e}", tree.pos)
+              throw e
+          }
+        }
+      }
+      tastys.foreach{ tasty =>
+        traverser.traverseTree(tasty.ast)(tasty.ast.symbol)
+      }
+    }
+  }
+  TastyInspector.inspectTastyFiles(tastyFiles)(inspector)
+}
+
+object App {
+  import scala.compiletime.*
+
+  transparent inline def summonFirst0[T]: Any =
+    inline erasedValue[T] match
+      case _: (a *: b) => summonFrom {
+        case instance: `a` => instance
+        case _ => summonFirst0[b]
+      }
+}