closes #2421: more complete fix, now also check...

closes #2421: more complete fix, now also check validity of inferred
type arguments for expressions inferred for implicit values review by
odersky

1 files changed, 8 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index 9657cea101..c4464010c1 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -459,7 +459,9 @@ self: Analyzer =>
               if (traceImplicits) println("tvars = "+tvars+"/"+(tvars map (_.constr)))
               val targs = solvedTypes(tvars, undetParams, undetParams map varianceInType(pt),
                                       false, lubDepth(List(itree2.tpe, pt)))
-              checkBounds(itree2.pos, NoPrefix, NoSymbol, undetParams, targs, "inferred ") // #2421
+
+              // #2421: check that we correctly instantiated type parameters outside of the implicit tree:
+              checkBounds(itree2.pos, NoPrefix, NoSymbol, undetParams, targs, "inferred ")
 
               // filter out failures from type inference, don't want to remove them from undetParams!
               // we must be conservative in leaving type params in undetparams
@@ -472,6 +474,11 @@ self: Analyzer =>
               val subst = new TreeTypeSubstituter(okParams, okArgs)
               subst traverse itree2
 
+              // #2421b: since type inference (which may have been performed during implicit search)
+              // does not check whether inferred arguments meet the bounds of the corresponding parameter (see note in solvedTypes),
+              // must check again here:
+              typed1(itree2, EXPRmode, wildPt)
+
               val result = new SearchResult(itree2, subst)
               incCounter(foundImplicits)
               if (traceImplicits) println("RESULT = "+result)