Merge pull request #3936 from som-snytt/issue/8806

SI-8806 Add lower bound check to Any lint

3 files changed, 20 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 421021163e..ee2775ee26 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -544,7 +544,14 @@ trait Infer extends Checkable {
       val targs = solvedTypes(tvars, tparams, tparams map varianceInTypes(formals), upper = false, lubDepth(formals) max lubDepth(argtpes))
       // Can warn about inferring Any/AnyVal as long as they don't appear
       // explicitly anywhere amongst the formal, argument, result, or expected type.
-      def canWarnAboutAny = !(pt :: restpe :: formals ::: argtpes exists (t => (t contains AnyClass) || (t contains AnyValClass)))
+      // ...or lower bound of a type param, since they're asking for it.
+      def canWarnAboutAny = {
+        val loBounds = tparams map (_.info.bounds.lo)
+        val hasAny = pt :: restpe :: formals ::: argtpes ::: loBounds exists (t =>
+          (t contains AnyClass) || (t contains AnyValClass)
+        )
+        !hasAny
+      }
       def argumentPosition(idx: Int): Position = context.tree match {
         case x: ValOrDefDef => x.rhs match {
           case Apply(fn, args) if idx < args.size => args(idx).pos
diff --git a/test/files/neg/warn-inferred-any.check b/test/files/neg/warn-inferred-any.check
index 4628033e55..8ad81d1529 100644
--- a/test/files/neg/warn-inferred-any.check
+++ b/test/files/neg/warn-inferred-any.check
@@ -7,6 +7,9 @@ warn-inferred-any.scala:16: warning: a type was inferred to be `AnyVal`; this ma
 warn-inferred-any.scala:17: warning: a type was inferred to be `AnyVal`; this may indicate a programming error.
   { 1l to 5l contains 5d }
              ^
+warn-inferred-any.scala:25: warning: a type was inferred to be `Any`; this may indicate a programming error.
+  def za = f(1, "one")
+             ^
 error: No warnings can be incurred under -Xfatal-warnings.
-three warnings found
+four warnings found
 one error found
diff --git a/test/files/neg/warn-inferred-any.scala b/test/files/neg/warn-inferred-any.scala
index b853e6e5a8..693c33e7be 100644
--- a/test/files/neg/warn-inferred-any.scala
+++ b/test/files/neg/warn-inferred-any.scala
@@ -17,3 +17,11 @@ trait Ys[+A] {
   { 1l to 5l contains 5d }
   { 1l to 5l contains 5l }
 }
+
+trait Zs {
+  def f[A](a: A*) = 42
+  def g[A >: Any](a: A*) = 42  // don't warn
+
+  def za = f(1, "one")
+  def zu = g(1, "one")
+}