Fix tryExtensionOrConversion

Author: odersky

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2924,19 +2924,24 @@ class Typer extends Namer
       (using Context): Tree =
 
     def selectionProto = SelectionProto(tree.name, mbrProto, compat, privateOK)
-    // try an extension method in scope
-    try
-      val nestedCtx = ctx.fresh.setNewTyperState()
+
+    def tryExtension(using Context): Tree =
       findRef(tree.name, WildcardType, ExtensionMethod, EmptyFlags, qual.srcPos) match
         case ref: TermRef =>
-          val app = extMethodApply(untpd.ref(ref).withSpan(tree.span), qual, pt)
-          if !nestedCtx.reporter.hasErrors then
-            nestedCtx.typerState.commit()
-            return app
-          for err <- nestedCtx.reporter.allErrors.take(1) do
-            rememberSearchFailure(qual,
-              SearchFailure(app.withType(FailedExtension(app, selectionProto, err.msg))))
+          extMethodApply(untpd.ref(ref).withSpan(tree.span), qual, pt)
         case _ =>
+          EmptyTree
+
+    // try an extension method in scope
+    try
+      val nestedCtx = ctx.fresh.setNewTyperState()
+      val app = tryExtension(using nestedCtx)
+      if !app.isEmpty && !nestedCtx.reporter.hasErrors then
+        nestedCtx.typerState.commit()
+        return app
+      for err <- nestedCtx.reporter.allErrors.take(1) do
+        rememberSearchFailure(qual,
+          SearchFailure(app.withType(FailedExtension(app, selectionProto, err.msg))))
     catch case ex: TypeError =>
       rememberSearchFailure(qual,
         SearchFailure(qual.withType(NestedFailure(ex.toMessage, selectionProto))))