From ee44db864654d85bedbb380aa9ee62d74483a59e Mon Sep 17 00:00:00 2001
From: Dale Wijnand <dale.wijnand@gmail.com>
Date: Mon, 23 Jan 2023 11:47:29 +0000
Subject: [PATCH] Fix early returns nested in trace

Found by enabling the tracing config.
---
 .../src/dotty/tools/dotc/transform/patmat/Space.scala |  5 +++--
 compiler/src/dotty/tools/dotc/typer/Implicits.scala   | 11 +++++------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala b/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
index 90310a385d0c..f4c4863d073d 100644
--- a/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
+++ b/compiler/src/dotty/tools/dotc/transform/patmat/Space.scala
@@ -489,9 +489,10 @@ class SpaceEngine(using Context) extends SpaceLogic {
   private def erase(tp: Type, inArray: Boolean = false, isValue: Boolean = false): Type = trace(i"$tp erased to", debug) {
 
     tp match {
-      case tp @ AppliedType(tycon, args) =>
-        if tycon.typeSymbol.isPatternBound then return WildcardType
+      case tp @ AppliedType(tycon, args) if tycon.typeSymbol.isPatternBound =>
+        WildcardType
 
+      case tp @ AppliedType(tycon, args) =>
         val args2 =
           if (tycon.isRef(defn.ArrayClass)) args.map(arg => erase(arg, inArray = true, isValue = false))
           else args.map(arg => erase(arg, inArray = false, isValue = false))
diff --git a/compiler/src/dotty/tools/dotc/typer/Implicits.scala b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
index 3e0e7dd5879d..c04f9b990bc7 100644
--- a/compiler/src/dotty/tools/dotc/typer/Implicits.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Implicits.scala
@@ -1002,11 +1002,10 @@ trait Implicits:
         if (argument.isEmpty) i"missing implicit parameter of type $pt after typer at phase ${ctx.phase.phaseName}"
         else i"type error: ${argument.tpe} does not conform to $pt${err.whyNoMatchStr(argument.tpe, pt)}")
 
-      if pt.unusableForInference
-         || !argument.isEmpty && argument.tpe.unusableForInference
-      then return NoMatchingImplicitsFailure
+      val usableForInference = !pt.unusableForInference
+        && (argument.isEmpty || !argument.tpe.unusableForInference)
 
-      val result0 =
+      val result0 = if usableForInference then
         // If we are searching implicits when resolving an import symbol, start the search
         // in the first enclosing context that does not have the same scope and owner as the current
         // context. Without that precaution, an eligible implicit in the current scope
@@ -1023,7 +1022,7 @@ trait Implicits:
         catch case ce: CyclicReference =>
           ce.inImplicitSearch = true
           throw ce
-      end result0
+      else NoMatchingImplicitsFailure
 
       val result =
         result0 match {
@@ -1052,7 +1051,7 @@ trait Implicits:
                   result
               }
             else result
-          case NoMatchingImplicitsFailure =>
+          case NoMatchingImplicitsFailure if usableForInference =>
             SearchFailure(new NoMatchingImplicits(pt, argument, ctx.typerState.constraint), span)
           case _ =>
             result0