SI-9231 Don't attempt implicit search for erroneous parameter

If the instantiated type of an implicit parameter is erroneous,
we should not attempt the implicit search. This avoids the following
useless error message in the enclosed test:

    error: ambiguous implicit values: ... match expected type M[<error>]

3 files changed, 14 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 3a85d16f55..377404b564 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -151,7 +151,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
           for(ar <- argResultsBuff)
             paramTp = paramTp.subst(ar.subst.from, ar.subst.to)
 
-          val res = if (paramFailed || (paramTp.isError && {paramFailed = true; true})) SearchFailure else inferImplicit(fun, paramTp, context.reportErrors, isView = false, context)
+          val res = if (paramFailed || (paramTp.isErroneous && {paramFailed = true; true})) SearchFailure else inferImplicit(fun, paramTp, context.reportErrors, isView = false, context)
           argResultsBuff += res
 
           if (res.isSuccess) {
diff --git a/test/files/neg/t9231.check b/test/files/neg/t9231.check
new file mode 100644
index 0000000000..43c14f53ca
--- /dev/null
+++ b/test/files/neg/t9231.check
@@ -0,0 +1,4 @@
+t9231.scala:8: error: not found: type DoesNotExist
+  foo[DoesNotExist]
+      ^
+one error found
diff --git a/test/files/neg/t9231.scala b/test/files/neg/t9231.scala
new file mode 100644
index 0000000000..05b1d24e9a
--- /dev/null
+++ b/test/files/neg/t9231.scala
@@ -0,0 +1,9 @@
+class M[A]
+class C {
+  implicit def M1: M[Int] = null
+  implicit def M2: M[String] = null
+
+  def foo[A](implicit M: M[A]) = null
+
+  foo[DoesNotExist]
+}