Merge pull request #12353 from dotty-staging/fix-12344

Fix #12344: tune splicing of default getters

Author: liufengyun

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

@@ -261,7 +261,20 @@ object Applications {
   /** Splice new method reference `meth` into existing application `app` */
   private def spliceMeth(meth: Tree, app: Tree)(using Context): Tree = app match {
     case Apply(fn, args) =>
-      spliceMeth(meth, fn).appliedToArgs(args)
+      // Constructors always have one leading non-implicit parameter list.
+      // Empty list is inserted for constructors where the first parameter list is implicit.
+      //
+      // Therefore, we need to ignore the first empty argument list.
+      // This is needed for the test tests/neg/i12344.scala
+      //
+      // see NamerOps.normalizeIfConstructor
+      //
+      if args == Nil
+         && !fn.isInstanceOf[Apply]
+         && app.tpe.isImplicitMethod
+         && fn.symbol.isConstructor
+      then meth
+      else spliceMeth(meth, fn).appliedToArgs(args)
     case TypeApply(fn, targs) =>
       // Note: It is important that the type arguments `targs` are passed in new trees
       // instead of being spliced in literally. Otherwise, a type argument to a default

tests/neg/i12344.scala

@@ -0,0 +1,26 @@
+import scala.quoted.*
+
+class C(using q: Quotes)(i: Int = 1, f: q.reflect.Flags = q.reflect.Flags.EmptyFlags)
+
+def test1a(using q: Quotes) = new C()                           // error
+def test2a(using q: Quotes) = new C(1)                          // error
+def test3a(using q: Quotes) = new C(1, q.reflect.Flags.Lazy)    // error
+def test4a(using q: Quotes) = new C(f = q.reflect.Flags.Lazy)   // error
+
+def test1b(using q: Quotes) = C()                               // error
+def test2b(using q: Quotes) = C(1)                              // error
+def test3b(using q: Quotes) = C(1, q.reflect.Flags.Lazy)        // error
+def test4b(using q: Quotes) = C(f = q.reflect.Flags.Lazy)       // error
+
+def test1c(using q: Quotes) = new C(using q)()
+def test2c(using q: Quotes) = new C(using q)(1)
+def test3c(using q: Quotes) = new C(using q)(1, q.reflect.Flags.Lazy)
+def test4c(using q: Quotes) = new C(using q)(f = q.reflect.Flags.Lazy)
+
+def test1d(using q: Quotes) = C(using q)()
+def test2d(using q: Quotes) = C(using q)(1)
+def test3d(using q: Quotes) = C(using q)(1, q.reflect.Flags.Lazy)
+def test4d(using q: Quotes) = C(using q)(f = q.reflect.Flags.Lazy)
+
+def test1e(using q: Quotes) = new C()()
+def test2e(using q: Quotes) = C()()