SI-7876 Scaladoc crasher due to regression in isFunctionType.

`isFunctionType` and `isTupleType` started returing true for
type constructors as of aeb73314. This led to a crash in type
printing in ScalaDoc (specfically, in ModelFactoryTypeSupport.scala)

This commit:
  - fixes those methods by guarding with !isHigherKinded
  - unit tests said methods
  - tests the reported crasher with a ScalaDoc test.

1 files changed, 26 insertions, 0 deletions

diff --git a/test/files/run/t7876.scala b/test/files/run/t7876.scala
new file mode 100644
index 0000000000..aeec8c8cce
--- /dev/null
+++ b/test/files/run/t7876.scala
@@ -0,0 +1,26 @@
+import scala.tools.partest._
+
+// Type constructors for FunctionN and TupleN should not be considered as function type / tuple types.
+object Test extends DirectTest {
+  override def extraSettings: String = "-usejavacp"
+
+  def code = ""
+
+  def show() {
+    val global = newCompiler()
+    new global.Run()
+    import global._, definitions._
+    val function0TC = FunctionClass(0).typeConstructor
+    val tuple1TC = TupleClass(1).typeConstructor
+    FunctionClass.seq.foreach { sym =>
+      val tc = sym.typeConstructor
+      assert(!isFunctionType(tc), s"$tc")
+      assert(!isFunctionTypeDirect(tc), s"$tc (direct)")
+    }
+    TupleClass.seq.foreach { sym =>
+      val tc = sym.typeConstructor
+      assert(!isTupleType(tc), s"$sym")
+      assert(!isTupleTypeDirect(tc), s"$tc (direct)")
+    }
+  }
+}