Add support for applied constructor sugar

Author: mbovel

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2515,17 +2515,19 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
   }
 
   def typedAppliedTypeTree(tree: untpd.AppliedTypeTree)(using Context): Tree = {
+    val tpt1 = withoutMode(Mode.Pattern):
+      typed(tree.tpt, AnyTypeConstructorProto)
+
     tree.args match
       case arg :: _ if arg.isTerm =>
         if Feature.dependentEnabled then
-          return errorTree(tree, em"Not yet implemented: T(...)")
+          tpt1.tpe.typeSymbol.primaryConstructor.typeRef.underlying match
+            case mt: MethodType =>
+              return TypeTree(mt.instantiate(tree.args.map((typedExpr(_).tpe))))
         else
           return errorTree(tree, dependentMsg)
       case _ =>
-
-    val tpt1 = withoutMode(Mode.Pattern) {
-      typed(tree.tpt, AnyTypeConstructorProto)
-    }
+    
     val tparams = tpt1.tpe.typeParams
      if tpt1.tpe.isError then
        val args1 = tree.args.mapconserve(typedType(_))