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Splicing of default getters should not special case constructors with implicits #22344

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Splicing of default getters should not special case constructors with implicits #22344

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16 changes: 1 addition & 15 deletions compiler/src/dotty/tools/dotc/typer/Applications.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -365,21 +365,7 @@ 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) =>
// 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
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@hamzaremmal hamzaremmal Jan 10, 2025 •
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Just to keep track of some info, this test is now tests/neg-macros/i12344.scala and it seems that some of the discussions that led to this change are not relevant now (See #12344 (comment) and https://github.com/scala/scala3/pull/14840/files#diff-a602b2ba421d0da906b1d1915ca14c84b336da38e2ab907b695c441c5d58f5b3)

//
// see NamerOps.normalizeIfConstructor
//
if args == Nil
&& !fn.isInstanceOf[Apply]
&& app.tpe.isImplicitMethod
&& fn.symbol.isConstructor
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I think that we should rather add another condition that checks if meth actually requires the empty argument list i.e.

&& !meth.tpe.widen.isNullaryMethod

then meth
else spliceMeth(meth, fn).appliedToArgs(args)
case Apply(fn, args) => 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
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5 changes: 5 additions & 0 deletions tests/pos/i22061.scala
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@@ -0,0 +1,5 @@
abstract class A()(implicit val x: Int = 3)
trait B extends A

abstract class C()(using y: Int = 9)
class D extends C()
Comment on lines +1 to +5
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If you extend the test case to one that also includes the syntactically inserted param lists, you will see that the current fix doesn't work. Test case:

abstract class A()(implicit val x: Int = 3)
class A1 extends A
class A2 extends A()

abstract class B()(using y: Int = 9)
class B1 extends B
class B2 extends B()

abstract class C(implicit val x: Int = 3)
class C1 extends C
class C2 extends C()

abstract class D(using y: Int = 9)
class D1 extends D
class D2 extends D()

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I would probably even extend it to:

abstract class A()(implicit val x: Int = 3)
class A1 extends A
class A2 extends A()

abstract class B()(using y: Int = 9)
class B1 extends B
class B2 extends B()

abstract class C(implicit val x: Int = 3)
class C1 extends C
class C2 extends C()

abstract class D(using y: Int = 9)
class D1 extends D
class D2 extends D()

abstract class E()(implicit val x: Int = 3, val y: Int = 4)
class E1 extends E
class E2 extends E()

abstract class F()(using y: Int = 9, x: Int = 8)
class F1 extends F
class F2 extends F()

abstract class G(implicit val x: Int = 3, val y: Int = 4)
class G1 extends G
class G2 extends G()

abstract class H(using y: Int = 9, x: Int = 8)
class H1 extends H
class H2 extends H()

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