Reuse typed prefix for applyDynamic and applyDynamicNamed

Fixes #16544

Author: nicolasstucki

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

@@ -1002,7 +1002,10 @@ trait Applications extends Compatibility {
             case TypeApply(fun, _) => !fun.isInstanceOf[Select]
             case _ => false
           }
-          typedDynamicApply(tree, isInsertedApply, pt)
+          val tree1 = fun1 match
+            case Select(_, nme.apply) => tree
+            case _ => untpd.Apply(fun1, tree.args)
+          typedDynamicApply(tree1, isInsertedApply, pt)
         case _ =>
           if (originalProto.isDropped) fun1
           else if (fun1.symbol == defn.Compiletime_summonFrom)

tests/pos/i16544a.scala

@@ -0,0 +1,49 @@
+import scala.language.dynamics
+
+object Foo extends Dynamic:
+  def applyDynamic(name: String)(): Foo.type = this
+
+object Test:
+  def test(): Foo.type =
+    Foo.xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()
+      .xxx()

tests/pos/i16544b.scala

@@ -0,0 +1,49 @@
+import scala.language.dynamics
+
+object Foo extends Dynamic:
+  def applyDynamicNamed(name: String)(args: (String, Int)): Foo.type = this
+
+object Test:
+  def test(): Foo.type =
+    Foo.xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)
+      .xxx(a = 1)

tests/pos/i16544c.scala

@@ -0,0 +1,49 @@
+import scala.language.dynamics
+
+object Foo extends Dynamic:
+  def selectDynamic(name: String): Foo.type = this
+
+object Test:
+  def test(): Foo.type =
+    Foo.xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx
+      .xxx

tests/pos/i16544d.scala

@@ -0,0 +1,49 @@
+import scala.language.dynamics
+
+object Foo extends Dynamic:
+  def applyDynamic(name: String)(): Foo.type = this
+  def applyDynamicNamed(name: String)(args: (String, Int)): Foo.type = this
+  def selectDynamic(name: String): Foo.type = this
+
+object Test:
+  def test(): Foo.type =
+    Foo.xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx
+      .xxx()
+      .xxx(a = 1)
+      .xxx