SI-8675 Avoid unreported error after second try using implicit view

This is specific to situations in which we first typecheck an
application `qual.m(arg)` against the method `m` directly provided
by `qual`, and then fall back to `implicitView(qual).m(arg)`.

Regressed in SI-3971 / 7fa77af, in which error reports were moved
to the innermost `Apply`, and the check for `errorInResult` was
accordingly changed to recurse through `Apply` trees.

Before that change, we did not fall back to using a view. After the
change, we do try a view. We retypecheck the arguments under the
`retyping` mode (see `tryTypedArgs`), but this doesn't seem to
be enough to avoid leaking the error typed nested trees from the
first try.

Here's an example from the enclosed test case:

    a.update(0, x[A]({new isString(true)}))
                                   `-- error typed

    refArrayOps(a).update(0, x[A]({new isString(true)}))
                             `                  `-- error type persists
                              `-- this tree is retypecked by tryTypedArgs

This commit changes `onError` to only proceed with the second
try if the retyped argument trees are error free.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 66b1c2d87a..9a4d5e3c06 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -4399,7 +4399,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
           if (retry) {
             val Select(qual, name) = fun
             tryTypedArgs(args, forArgMode(fun, mode)) match {
-              case Some(args1) =>
+              case Some(args1) if !args1.exists(arg => arg.exists(_.isErroneous)) =>
                 val qual1 =
                   if (!pt.isError) adaptToArguments(qual, name, args1, pt, reportAmbiguous = true, saveErrors = true)
                   else qual