SI-10081 Avoid diverging implicit scope search

Storing empty infos into the infoMap (thus avoiding recomputation) prevents the endless recursion. This is an alternative to #5734 that avoids the expensive annotation removal and the regression in pos/t1203a.scala.
scala · Feb 27, 2017 · ebe1180 · ebe1180
1 parent 920bc4e
commit ebe1180
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Showing 3 changed files with 7 additions and 2 deletions.
diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -1042,8 +1042,7 @@ trait Implicits {
                   if (sym.isPackageClass) sym.packageObject.typeOfThis
                   else singleType(pre, companionSymbolOf(sym, context))
                 val infos = pre1.implicitMembers.iterator.map(mem => new ImplicitInfo(mem.name, pre1, mem)).toList
-                if (infos.nonEmpty)
-                  infoMap += (sym -> infos)
+                infoMap += (sym -> infos)
               }
               val bts = tp.baseTypeSeq
               var i = 1

diff --git a/test/files/neg/t10081.check b/test/files/neg/t10081.check
@@ -0,0 +1,4 @@
+t10081.scala:2: error: value x is not a member of B[X]
+trait B[X] extends A[B[X @unchecked]] { this.x }
+                                             ^
+one error found
diff --git a/test/files/neg/t10081.scala b/test/files/neg/t10081.scala
@@ -0,0 +1,2 @@
+trait A[_]
+trait B[X] extends A[B[X @unchecked]] { this.x }