Merge pull request #6982 from ashwinbhaskar/master

Add empty case class params check. Add test.

Author: allanrenucci

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -446,7 +446,7 @@ object desugar {
  val constrTparams = impliedTparams.map(toDefParam(_, keepAnnotations = false))
  val constrVparamss =
  if (originalVparamss.isEmpty) { // ensure parameter list is non-empty
- if (isCaseClass && originalTparams.isEmpty)
+ if (isCaseClass)
  ctx.error(CaseClassMissingParamList(cdef), namePos)
  ListOfNil
  } else if (isCaseClass && originalVparamss.head.exists(_.mods.isOneOf(GivenOrImplicit))) {

tests/neg/EmptyCaseClassParams.check

@@ -0,0 +1,18 @@
+-- [E004] Syntax Error: tests/neg/EmptyCaseClassParams.scala:2:13 ------------------------------------------------------
+2 | case class A[T] // error
+ | ^
+ | A case class must have at least one parameter list
+
+longer explanation available when compiling with `-explain`
+-- [E004] Syntax Error: tests/neg/EmptyCaseClassParams.scala:5:13 ------------------------------------------------------
+5 | case class B[T] // error
+ | ^
+ | A case class must have at least one parameter list
+
+longer explanation available when compiling with `-explain`
+-- [E004] Syntax Error: tests/neg/EmptyCaseClassParams.scala:9:9 -------------------------------------------------------
+9 | case D[T] extends Foo[T] // error
+ | ^
+ | A case class must have at least one parameter list
+
+longer explanation available when compiling with `-explain`

tests/neg/EmptyCaseClassParams.scala

@@ -0,0 +1,11 @@
+object EmptyCaseClassParams{
+ case class A[T] // error
+
+ class C
+ case class B[T] // error
+ extends C
+
+ enum Foo[T]{
+ case D[T] extends Foo[T] // error
+ }
+}

tests/neg/derive-eq.scala

@@ -9,7 +9,7 @@ enum Lst[T] derives Eql {
  case Nil()
 }
 
-case class Triple[S, T, U] derives Eql
+case class Triple[S, T, U]() derives Eql
 
 
 object Test extends App {

tests/neg/enumsAccess.scala

@@ -5,7 +5,7 @@ object test1 {
  enum E4 {
  case C1(x: INT) // error: illegal reference
  case C2(x: Int = defaultX) // error: illegal reference
- case C3[T <: INT] // error: illegal reference
+ case C3[T <: INT]() // error: illegal reference
  }
 
  object E4 {
@@ -24,7 +24,7 @@ object test2 {
  enum E5 {
  case C1(x: INT) // ok
  case C2(x: Int = defaultX) // ok
- case C3[T <: INT] // ok
+ case C3[T <: INT]() // ok
  }
 }
 
@@ -39,7 +39,7 @@ object test3 {
  enum E5 {
  case C1(x: INT) // ok
  case C2(x: Int = defaultX)// ok
- case C3[T <: INT] // ok
+ case C3[T <: INT]() // ok
  }
 }
 
@@ -48,7 +48,7 @@ object test4 {
  enum E5 {
  case C1(x: INT) // error: illegal reference
  case C2(x: Int = defaultX) // error: illegal reference
- case C3[T <: INT] // error: illegal reference
+ case C3[T <: INT]() // error: illegal reference
  }
 
  import E5._
@@ -76,7 +76,7 @@ object test6 {
  import E5._
  enum E5[T](x: T) {
  case C3() extends E5[INT](defaultX) // ok
- case C4 extends E5[INT](defaultX) // ok
+ case C4() extends E5[INT](defaultX) // ok
  }
 
  object E5 {
@@ -90,7 +90,7 @@ object test7 {
  trait Arg
 
  enum E(x: Arg) {
- case C extends E(this) // error: illegal reference to `this`
+ case C() extends E(this) // error: illegal reference to `this`
  }
  object E extends Arg
 }

tests/neg/parser-stability-19.scala

@@ -1,5 +1,5 @@
 object x0 {
- case class x0[] // error // error
+ case class x0[]() // error // error
  def x0( ) ] // error // error
  def x0 ( x0:x0 ):x0.type = x1 x0 // error // error
 // error

tests/neg/typeclass-derivation2.scala

@@ -101,10 +101,10 @@ object TypeLevel {
  enum Shape {
 
  /** A sum with alternative types `Alts` */
- case Cases[Alts <: Tuple]
+ case Cases[Alts <: Tuple]()
 
  /** A product type `T` with element types `Elems` */
- case Case[T, Elems <: Tuple]
+ case Case[T, Elems <: Tuple]()
  }
 
  /** Every generic derivation starts with a typeclass instance of this type.

tests/pos/gadt-GadtStlc.scala

@@ -10,7 +10,7 @@ object GadtStlc {
  // Var[M[W]]
  sealed trait Var[A]
  object VarW extends Var[W]
- case class VarM[A] extends Var[M[A]]
+ case class VarM[A]() extends Var[M[A]]
 
  // \s.e
  sealed trait Abs[S, E]

tests/pos/i4176-gadt.scala

@@ -1,7 +1,7 @@
 object i4176 {
  sealed trait TNat
  case class TZero() extends TNat
- case class TSucc[N <: TNat] extends TNat
+ case class TSucc[N <: TNat]() extends TNat
 
  object TNatSum {
  sealed trait TSum[M, N, R]

tests/pos/i4316.scala

@@ -1,6 +1,6 @@
 object Test {
 
- case class Bar[A]
+ case class Bar[A]()
 
  def meth[A](consumer: A => Unit, s: Bar[A]): Unit = {
  s match {