diff --git a/compiler/src/dotty/tools/dotc/reporting/ExploringReporter.scala b/compiler/src/dotty/tools/dotc/reporting/ExploringReporter.scala
index f469c03764c0..99720b8e4d29 100644
--- a/compiler/src/dotty/tools/dotc/reporting/ExploringReporter.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/ExploringReporter.scala
@@ -18,6 +18,9 @@ class ExploringReporter extends StoreReporter(null, fromTyperState = false):
   override def removeBufferedMessages(using Context): List[Diagnostic] =
     try infos.toList finally reset()
 
+  override def mapBufferedMessages(f: Diagnostic => Diagnostic)(using Context): Unit =
+    infos.mapInPlace(f)
+
   def reset(): Unit = infos.clear()
 
-end ExploringReporter
\ No newline at end of file
+end ExploringReporter
diff --git a/compiler/src/dotty/tools/dotc/reporting/Reporter.scala b/compiler/src/dotty/tools/dotc/reporting/Reporter.scala
index db63cd7a7ce4..84969a21acac 100644
--- a/compiler/src/dotty/tools/dotc/reporting/Reporter.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/Reporter.scala
@@ -264,9 +264,7 @@ abstract class Reporter extends interfaces.ReporterResult {
   def removeBufferedMessages(using Context): List[Diagnostic] = Nil
 
   /** If this reporter buffers messages, apply `f` to all buffered messages. */
-  def mapBufferedMessages(f: Diagnostic => Diagnostic)(using Context): Unit =
-    val mappedDiagnostics = removeBufferedMessages.map(f)
-    mappedDiagnostics.foreach(report)
+  def mapBufferedMessages(f: Diagnostic => Diagnostic)(using Context): Unit = ()
 
   /** Issue all messages in this reporter to next outer one, or make sure they are written. */
   def flush()(using Context): Unit =
diff --git a/compiler/src/dotty/tools/dotc/reporting/StoreReporter.scala b/compiler/src/dotty/tools/dotc/reporting/StoreReporter.scala
index 532aeab9d383..9395788d4cc7 100644
--- a/compiler/src/dotty/tools/dotc/reporting/StoreReporter.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/StoreReporter.scala
@@ -37,6 +37,9 @@ class StoreReporter(outer: Reporter | Null = Reporter.NoReporter, fromTyperState
     if (infos != null) try infos.uncheckedNN.toList finally infos = null
     else Nil
 
+  override def mapBufferedMessages(f: Diagnostic => Diagnostic)(using Context): Unit =
+    if infos != null then infos.uncheckedNN.mapInPlace(f)
+
   override def pendingMessages(using Context): List[Diagnostic] =
     if (infos != null) infos.uncheckedNN.toList else Nil
 
diff --git a/compiler/src/dotty/tools/dotc/typer/Applications.scala b/compiler/src/dotty/tools/dotc/typer/Applications.scala
index cb7f6cb9cf54..bac82e1deb8f 100644
--- a/compiler/src/dotty/tools/dotc/typer/Applications.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Applications.scala
@@ -1097,6 +1097,7 @@ trait Applications extends Compatibility {
                                   case _ => dia
                               case msg => dia
                           case dia => dia
+                      case _ => ()
 
                 // Try once with original prototype and once (if different) with tupled one.
                 // The reason we need to try both is that the decision whether to use tupled