Merge pull request #974 from adriaanm/repull-unchecked-hk

Improve unchecked warnings.

5 files changed, 36 insertions, 6 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index 22e78a1e36..bcbcb96400 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -1352,8 +1352,10 @@ trait Infer {
             } else {
               for (arg <- args) {
                 if (sym == ArrayClass) check(arg, bound)
-                else if (arg.typeArgs.nonEmpty) ()              // avoid spurious warnings with higher-kinded types
-                else if (sym == NonLocalReturnControlClass) ()  // no way to suppress unchecked warnings on try/catch
+                // avoid spurious warnings with higher-kinded types
+                else if (arg.typeArgs exists (_.typeSymbol.isTypeParameterOrSkolem)) ()
+                // no way to suppress unchecked warnings on try/catch
+                else if (sym == NonLocalReturnControlClass) ()
                 else arg match {
                   case TypeRef(_, sym, _) if isLocalBinding(sym) =>
                     ;
@@ -1497,7 +1499,7 @@ trait Infer {
         )
 
       // Intentionally *not* using `Type#typeSymbol` here, which would normalize `tp`
-      // and collect symbols from the result type of any resulting `PolyType`s, which 
+      // and collect symbols from the result type of any resulting `PolyType`s, which
       // are not free type parameters of `tp`.
       //
       // Contrast with `isFreeTypeParamNoSkolem`.
@@ -1530,7 +1532,7 @@ trait Infer {
     def inferExprAlternative(tree: Tree, pt: Type) = tree.tpe match {
       case OverloadedType(pre, alts) => tryTwice { isSecondTry =>
         val alts0          = alts filter (alt => isWeaklyCompatible(pre.memberType(alt), pt))
-        val noAlternatives = alts0.isEmpty 
+        val noAlternatives = alts0.isEmpty
         val alts1          = if (noAlternatives) alts else alts0
 
         //println("trying "+alts1+(alts1 map (_.tpe))+(alts1 map (_.locationString))+" for "+pt)
@@ -1688,7 +1690,7 @@ trait Infer {
         val saved = context.state
         var fallback = false
         context.setBufferErrors()
-        // We cache the current buffer because it is impossible to 
+        // We cache the current buffer because it is impossible to
         // distinguish errors that occurred before entering tryTwice
         // and our first attempt in 'withImplicitsDisabled'. If the
         // first attempt fails we try with implicits on *and* clean
diff --git a/test/files/neg/unchecked2.check b/test/files/neg/unchecked2.check
new file mode 100644
index 0000000000..2c0be9ce00
--- /dev/null
+++ b/test/files/neg/unchecked2.check
@@ -0,0 +1,19 @@
+unchecked2.scala:2: error: non variable type-argument Int in type Option[Int] is unchecked since it is eliminated by erasure
+  Some(123).isInstanceOf[Option[Int]]
+                        ^
+unchecked2.scala:3: error: non variable type-argument String in type Option[String] is unchecked since it is eliminated by erasure
+  Some(123).isInstanceOf[Option[String]]
+                        ^
+unchecked2.scala:4: error: non variable type-argument List[String] in type Option[List[String]] is unchecked since it is eliminated by erasure
+  Some(123).isInstanceOf[Option[List[String]]]
+                        ^
+unchecked2.scala:5: error: non variable type-argument List[Int => String] in type Option[List[Int => String]] is unchecked since it is eliminated by erasure
+  Some(123).isInstanceOf[Option[List[Int => String]]]
+                        ^
+unchecked2.scala:6: error: non variable type-argument (String, Double) in type Option[(String, Double)] is unchecked since it is eliminated by erasure
+  Some(123).isInstanceOf[Option[(String, Double)]]
+                        ^
+unchecked2.scala:7: error: non variable type-argument String => Double in type Option[String => Double] is unchecked since it is eliminated by erasure
+  Some(123).isInstanceOf[Option[String => Double]]
+                        ^
+6 errors found
diff --git a/test/files/neg/unchecked2.flags b/test/files/neg/unchecked2.flags
new file mode 100644
index 0000000000..144ddac9d3
--- /dev/null
+++ b/test/files/neg/unchecked2.flags
@@ -0,0 +1 @@
+-unchecked -Xfatal-warnings
diff --git a/test/files/neg/unchecked2.scala b/test/files/neg/unchecked2.scala
new file mode 100644
index 0000000000..a2e757e1dc
--- /dev/null
+++ b/test/files/neg/unchecked2.scala
@@ -0,0 +1,8 @@
+object Test {
+  Some(123).isInstanceOf[Option[Int]]
+  Some(123).isInstanceOf[Option[String]]
+  Some(123).isInstanceOf[Option[List[String]]]
+  Some(123).isInstanceOf[Option[List[Int => String]]]
+  Some(123).isInstanceOf[Option[(String, Double)]]
+  Some(123).isInstanceOf[Option[String => Double]]
+}
diff --git a/test/files/pos/t1439.scala b/test/files/pos/t1439.scala
index 68a7332b2a..0efcc74b65 100644
--- a/test/files/pos/t1439.scala
+++ b/test/files/pos/t1439.scala
@@ -2,7 +2,7 @@
 class View[C[A]] { }
 
 object Test {
-  null match {
+  (null: Any) match {
     case v: View[_] =>
   }
 }