Fix #10966: handle local apply methods

compiler/src/dotty/tools/dotc/transform/SpecializeFunctions.scala

@@ -67,7 +67,7 @@ class SpecializeFunctions extends MiniPhase {
   /** Dispatch to specialized `apply`s in user code when available */
   override def transformApply(tree: Apply)(using Context) =
     tree match {
-      case Apply(fun: NameTree, args) if fun.name == nme.apply && args.size <= 3 =>
+      case Apply(fun: NameTree, args) if fun.name == nme.apply && args.size <= 3 && fun.symbol.owner.isType =>
         val argTypes = fun.tpe.widen.firstParamTypes.map(_.widenSingleton.dealias)
         val retType  = tree.tpe.widenSingleton.dealias
         val isSpecializable =

tests/pos/i10966.scala

@@ -0,0 +1,16 @@
+object Main {
+  def main(args: Array[String]): Unit = {
+    def apply(a: Int, b: Int): Unit = {}
+    apply(1, 2)
+
+    // The following will work:
+    def f(a: Int, b: Int): Unit = {}
+    f(1, 2)
+  }
+
+  def foo() = {
+    // The following will not work either:
+    def `apply`(a: Int): Unit = {}
+    `apply`(1)
+  }
+}