improves traces and error messages

1 files changed, 13 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index 217cadaab8..6a2a9b850c 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -1183,16 +1183,24 @@ trait Implicits {
             // if ``pre'' is not a PDT, e.g. if someone wrote
             //   implicitly[scala.reflect.makro.Context#TypeTag[Int]]
             // then we need to fail, because we don't know the prefix to use during type reification
-            return failure(tp, "tag error: unsupported prefix type %s (%s)".format(pre, pre.kind))
+            // upd. we also need to fail silently, because this is a very common situation
+            // e.g. quite often we're searching for BaseUniverse#TypeTag, e.g. for a type tag in any universe
+            // so that if we find one, we could convert it to whatever universe we need by the means of the `in` method
+            // if no tag is found in scope, we end up here, where we ask someone to materialize the tag for us
+            // however, since the original search was about a tag with no particular prefix, we cannot proceed
+            // this situation happens very often, so emitting an error message here (even if only for -Xlog-implicits) would be too much
+            //return failure(tp, "tag error: unsupported prefix type %s (%s)".format(pre, pre.kind))
+            return SearchFailure
         }
       )
       // todo. migrate hardcoded materialization in Implicits to corresponding implicit macros
-      var materializer = atPos(pos.focus)(
-        gen.mkMethodCall(TagMaterializers(tagClass), List(tp), List(prefix))
-      )
+      var materializer = atPos(pos.focus)(gen.mkMethodCall(TagMaterializers(tagClass), List(tp), List(prefix)))
       if (settings.XlogImplicits.value) println("materializing requested %s.%s[%s] using %s".format(pre, tagClass.name, tp, materializer))
       if (context.macrosEnabled) success(materializer)
-      else failure(materializer, "macros are disabled")
+      // don't call `failure` here. if macros are disabled, we just fail silently
+      // otherwise -Xlog-implicits will spam the long with zillions of "macros are disabled"
+      // this is ugly but temporary, since all this code will be removed once I fix implicit macros
+      else SearchFailure
     }
 
     private val ManifestSymbols = Set[Symbol](PartialManifestClass, FullManifestClass, OptManifestClass)