Fix #9161: Add toString to companion modules

Author: nicolasstucki

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

@@ -699,7 +699,10 @@ object desugar {
           DefDef(methName, derivedTparams, (unapplyParam :: Nil) :: Nil, unapplyResTp, unapplyRHS)
             .withMods(synthetic)
         }
-        companionDefs(companionParent, applyMeths ::: unapplyMeth :: companionMembers)
+        val toStringMeth =
+          DefDef(nme.toString_, Nil, Nil, TypeTree(), Literal(Constant(className.toString))).withMods(Modifiers(Override | Synthetic))
+
+        companionDefs(companionParent, applyMeths ::: unapplyMeth :: toStringMeth :: companionMembers)
       }
       else if (companionMembers.nonEmpty || companionDerived.nonEmpty || isEnum)
         companionDefs(anyRef, companionMembers)

tests/run-macros/tasty-extractors-2.check

@@ -49,7 +49,7 @@ TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
 Inlined(None, Nil, Block(List(ClassDef("Foo", DefDef("<init>", Nil, List(Nil), Inferred(), None), List(Apply(Select(New(Inferred()), "<init>"), Nil)), Nil, None, List(DefDef("a", Nil, Nil, Inferred(), Some(Literal(Constant(0))))))), Literal(Constant(()))))
 TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
 
-Inlined(None, Nil, Block(List(ClassDef("Foo", DefDef("<init>", Nil, List(Nil), Inferred(), None), List(Apply(Select(New(Inferred()), "<init>"), Nil), TypeSelect(Select(Ident("_root_"), "scala"), "Product"), TypeSelect(Select(Ident("_root_"), "scala"), "Serializable")), Nil, None, List(DefDef("copy", Nil, List(Nil), Inferred(), Some(Apply(Select(New(Inferred()), "<init>"), Nil))))), ValDef("Foo", TypeIdent("Foo$"), Some(Apply(Select(New(TypeIdent("Foo$")), "<init>"), Nil))), ClassDef("Foo$", DefDef("<init>", Nil, List(Nil), Inferred(), None), List(Apply(Select(New(Inferred()), "<init>"), Nil), Applied(Inferred(), List(Inferred())), TypeSelect(Select(Ident("_root_"), "scala"), "Serializable")), Nil, Some(ValDef("_", Singleton(Ident("Foo")), None)), List(DefDef("apply", Nil, List(Nil), Inferred(), Some(Apply(Select(New(Inferred()), "<init>"), Nil))), DefDef("unapply", Nil, List(List(ValDef("x$1", Inferred(), None))), Singleton(Literal(Constant(true))), Some(Literal(Constant(true))))))), Literal(Constant(()))))
+Inlined(None, Nil, Block(List(ClassDef("Foo", DefDef("<init>", Nil, List(Nil), Inferred(), None), List(Apply(Select(New(Inferred()), "<init>"), Nil), TypeSelect(Select(Ident("_root_"), "scala"), "Product"), TypeSelect(Select(Ident("_root_"), "scala"), "Serializable")), Nil, None, List(DefDef("copy", Nil, List(Nil), Inferred(), Some(Apply(Select(New(Inferred()), "<init>"), Nil))))), ValDef("Foo", TypeIdent("Foo$"), Some(Apply(Select(New(TypeIdent("Foo$")), "<init>"), Nil))), ClassDef("Foo$", DefDef("<init>", Nil, List(Nil), Inferred(), None), List(Apply(Select(New(Inferred()), "<init>"), Nil), Applied(Inferred(), List(Inferred())), TypeSelect(Select(Ident("_root_"), "scala"), "Serializable")), Nil, Some(ValDef("_", Singleton(Ident("Foo")), None)), List(DefDef("apply", Nil, List(Nil), Inferred(), Some(Apply(Select(New(Inferred()), "<init>"), Nil))), DefDef("unapply", Nil, List(List(ValDef("x$1", Inferred(), None))), Singleton(Literal(Constant(true))), Some(Literal(Constant(true)))), DefDef("toString", Nil, Nil, Inferred(), Some(Literal(Constant("Foo"))))))), Literal(Constant(()))))
 TypeRef(ThisType(TypeRef(NoPrefix(), "scala")), "Unit")
 
 Inlined(None, Nil, Block(List(ClassDef("Foo1", DefDef("<init>", Nil, List(List(ValDef("a", TypeIdent("Int"), None))), Inferred(), None), List(Apply(Select(New(Inferred()), "<init>"), Nil)), Nil, None, List(ValDef("a", Inferred(), None)))), Literal(Constant(()))))

tests/run/i9161.scala

@@ -0,0 +1,4 @@
+
+final case class T(i:Int)
+
+@main def Test = assert(T.toString == "T")

tests/semanticdb/metac.expect

@@ -339,7 +339,7 @@ Schema => SemanticDB v4
 Uri => Classes.scala
 Text => empty
 Language => Scala
-Symbols => 106 entries
+Symbols => 109 entries
 Occurrences => 130 entries
 
 Symbols:
@@ -364,6 +364,7 @@ classes/C3#x. => val method x
 classes/C3. => final object C3
 classes/C3.apply(). => method apply
 classes/C3.apply().(x) => param x
+classes/C3.toString(). => method toString
 classes/C3.unapply(). => method unapply
 classes/C3.unapply().(x$1) => param x$1
 classes/C4# => case class C4
@@ -377,6 +378,7 @@ classes/C4#x. => val method x
 classes/C4. => final object C4
 classes/C4.apply(). => method apply
 classes/C4.apply().(x) => param x
+classes/C4.toString(). => method toString
 classes/C4.unapply(). => method unapply
 classes/C4.unapply().(x$1) => param x$1
 classes/C6# => case class C6
@@ -390,6 +392,7 @@ classes/C6#x. => val method x
 classes/C6. => final object C6
 classes/C6.apply(). => method apply
 classes/C6.apply().(x) => param x
+classes/C6.toString(). => method toString
 classes/C6.unapply(). => method unapply
 classes/C6.unapply().(x$1) => param x$1
 classes/C7# => class C7
@@ -639,7 +642,7 @@ Schema => SemanticDB v4
 Uri => Enums.scala
 Text => empty
 Language => Scala
-Symbols => 157 entries
+Symbols => 159 entries
 Occurrences => 203 entries
 
 Symbols:
@@ -705,6 +708,7 @@ _empty_/Enums.Maybe.Just. => final object Just
 _empty_/Enums.Maybe.Just.apply(). => method apply
 _empty_/Enums.Maybe.Just.apply().(value) => param value
 _empty_/Enums.Maybe.Just.apply().[A] => typeparam A
+_empty_/Enums.Maybe.Just.toString(). => method toString
 _empty_/Enums.Maybe.Just.unapply(). => method unapply
 _empty_/Enums.Maybe.Just.unapply().(x$1) => param x$1
 _empty_/Enums.Maybe.Just.unapply().[A] => typeparam A
@@ -788,6 +792,7 @@ _empty_/Enums.`<:<`.Refl#copy().[C] => typeparam C
 _empty_/Enums.`<:<`.Refl. => final object Refl
 _empty_/Enums.`<:<`.Refl.apply(). => method apply
 _empty_/Enums.`<:<`.Refl.apply().[C] => typeparam C
+_empty_/Enums.`<:<`.Refl.toString(). => method toString
 _empty_/Enums.`<:<`.Refl.unapply(). => method unapply
 _empty_/Enums.`<:<`.Refl.unapply().(x$1) => param x$1
 _empty_/Enums.`<:<`.Refl.unapply().[C] => typeparam C
@@ -2071,7 +2076,7 @@ Schema => SemanticDB v4
 Uri => NamedApplyBlock.scala
 Text => empty
 Language => Scala
-Symbols => 45 entries
+Symbols => 46 entries
 Occurrences => 46 entries
 
 Symbols:
@@ -2100,6 +2105,7 @@ example/NamedApplyBlockCaseClassConstruction.Msg.apply(). => method apply
 example/NamedApplyBlockCaseClassConstruction.Msg.apply().(body) => param body
 example/NamedApplyBlockCaseClassConstruction.Msg.apply().(head) => param head
 example/NamedApplyBlockCaseClassConstruction.Msg.apply().(tail) => param tail
+example/NamedApplyBlockCaseClassConstruction.Msg.toString(). => method toString
 example/NamedApplyBlockCaseClassConstruction.Msg.unapply(). => method unapply
 example/NamedApplyBlockCaseClassConstruction.Msg.unapply().(x$1) => param x$1
 example/NamedApplyBlockCaseClassConstruction.bodyText. => val method bodyText
@@ -2177,7 +2183,7 @@ Schema => SemanticDB v4
 Uri => NamedArguments.scala
 Text => empty
 Language => Scala
-Symbols => 15 entries
+Symbols => 16 entries
 Occurrences => 13 entries
 
 Symbols:
@@ -2193,6 +2199,7 @@ example/NamedArguments#User#name. => val method name
 example/NamedArguments#User. => final object User
 example/NamedArguments#User.apply(). => method apply
 example/NamedArguments#User.apply().(name) => param name
+example/NamedArguments#User.toString(). => method toString
 example/NamedArguments#User.unapply(). => method unapply
 example/NamedArguments#User.unapply().(x$1) => param x$1
 example/NamedArguments#`<init>`(). => primary ctor <init>
@@ -2430,7 +2437,7 @@ Schema => SemanticDB v4
 Uri => Synthetic.scala
 Text => empty
 Language => Scala
-Symbols => 37 entries
+Symbols => 38 entries
 Occurrences => 163 entries
 
 Symbols:
@@ -2456,6 +2463,7 @@ example/Synthetic#s.Bar#`<init>`(). => primary ctor <init>
 example/Synthetic#s.Bar#copy(). => method copy
 example/Synthetic#s.Bar. => final object Bar
 example/Synthetic#s.Bar.apply(). => method apply
+example/Synthetic#s.Bar.toString(). => method toString
 example/Synthetic#s.Bar.unapply(). => method unapply
 example/Synthetic#s.Bar.unapply().(x$1) => param x$1
 example/Synthetic#s.apply(). => method apply
@@ -3113,7 +3121,7 @@ Schema => SemanticDB v4
 Uri => recursion.scala
 Text => empty
 Language => Scala
-Symbols => 35 entries
+Symbols => 36 entries
 Occurrences => 56 entries
 
 Symbols:
@@ -3145,6 +3153,7 @@ recursion/Nats.Succ. => final object Succ
 recursion/Nats.Succ.apply(). => method apply
 recursion/Nats.Succ.apply().(p) => param p
 recursion/Nats.Succ.apply().[N] => typeparam N
+recursion/Nats.Succ.toString(). => method toString
 recursion/Nats.Succ.unapply(). => method unapply
 recursion/Nats.Succ.unapply().(x$1) => param x$1
 recursion/Nats.Succ.unapply().[N] => typeparam N
@@ -3400,7 +3409,7 @@ Schema => SemanticDB v4
 Uri => semanticdb-Types.scala
 Text => empty
 Language => Scala
-Symbols => 140 entries
+Symbols => 142 entries
 Occurrences => 250 entries
 
 Symbols:
@@ -3428,6 +3437,7 @@ types/Foo#s. => val method s
 types/Foo. => final object Foo
 types/Foo.apply(). => method apply
 types/Foo.apply().(s) => param s
+types/Foo.toString(). => method toString
 types/Foo.unapply(). => method unapply
 types/Foo.unapply().(x$1) => param x$1
 types/Foo.x. => val method x
@@ -3479,6 +3489,7 @@ types/Test.C#RepeatedType#s. => val method s
 types/Test.C#RepeatedType. => final object RepeatedType
 types/Test.C#RepeatedType.apply(). => method apply
 types/Test.C#RepeatedType.apply().(s) => param s
+types/Test.C#RepeatedType.toString(). => method toString
 types/Test.C#RepeatedType.unapplySeq(). => method unapplySeq
 types/Test.C#RepeatedType.unapplySeq().(x$1) => param x$1
 types/Test.C#TypeType. => final object TypeType
@@ -3805,7 +3816,7 @@ Schema => SemanticDB v4
 Uri => semanticdb-extract.scala
 Text => empty
 Language => Scala
-Symbols => 17 entries
+Symbols => 18 entries
 Occurrences => 22 entries
 
 Symbols:
@@ -3821,6 +3832,7 @@ _empty_/AnObject.Foo#x. => val method x
 _empty_/AnObject.Foo. => final object Foo
 _empty_/AnObject.Foo.apply(). => method apply
 _empty_/AnObject.Foo.apply().(x) => param x
+_empty_/AnObject.Foo.toString(). => method toString
 _empty_/AnObject.Foo.unapply(). => method unapply
 _empty_/AnObject.Foo.unapply().(x$1) => param x$1
 _empty_/AnObject.foo(). => method foo