TASTy macro annotations class modifications (part 2)

Enable modification of classes with `TastyAnnotation`:
 * Can annotate `class` to transform it
 * Can annotate `object` to transform the companion class

Supported class modifications:
 * Modify the implementations of `def`, `val`, `var`, `lazy val`, `class`, `object` in the class
 * Add new `def`, `val`, `var`, `lazy val`, `class`, `object` members to the class
 * Add a new override for a `def`, `val`, `var`, `lazy val` members in the class

Restrictions:
 * An annotation on a top-level class cannot return a top-level `def`, `val`, `var`, `lazy val`

compiler/src/dotty/tools/dotc/transform/TastyAnnotations.scala

@@ -9,6 +9,7 @@ import dotty.tools.dotc.config.Printers.{macroAnnot => debug}
 import dotty.tools.dotc.core.Annotations.*
 import dotty.tools.dotc.core.Contexts.*
 import dotty.tools.dotc.core.Decorators.*
+import dotty.tools.dotc.core.Decorators.*
 import dotty.tools.dotc.core.DenotTransformers.DenotTransformer
 import dotty.tools.dotc.core.Flags.*
 import dotty.tools.dotc.core.MacroClassLoader
@@ -30,14 +31,10 @@ class TastyAnnotations(thisPhase: DenotTransformer):
   def expandAnnotations(tree: MemberDef)(using Context): List[DefTree] =
     if !hasTastyAnnotation(tree.symbol) then
       List(tree)
-    else if tree.symbol.is(Module) then
-      if tree.symbol.isClass then // error only reported on module class
-        report.error("TASTy annotations are not supported on object", tree)
-      List(tree)
-    else if tree.symbol.isClass then
-      report.error("TASTy annotations are not supported on class", tree)
+    else if tree.symbol.is(Module) && !tree.symbol.isClass then
+      // only class is transformed
       List(tree)
-    else if tree.symbol.isType then
+    else if tree.symbol.isType && !tree.symbol.isClass then
       report.error("TASTy annotations are not supported on type", tree)
       List(tree)
     else
@@ -71,7 +68,6 @@ class TastyAnnotations(thisPhase: DenotTransformer):
         else
           tree
       }
-
       allTrees += transformedTree
       insertedAfter.foreach(allTrees.++=)
 
@@ -99,11 +95,13 @@ class TastyAnnotations(thisPhase: DenotTransformer):
   private def checkAndEnter(newTree: Tree, annotated: Symbol, annot: Annotation)(using Context) =
     val sym = newTree.symbol
     if sym.isClass then
-      report.error("Generating classes is not supported", annot.tree)
+      report.error(i"TASTy annotation returning a `class` is not yet supported. $annot tried to add $sym", annot.tree)
     else if sym.isType then
-      report.error("Generating type is not supported", annot.tree)
+      report.error(i"TASTy annotation cannot return a `type`. $annot tried to add $sym", annot.tree)
     else if sym.owner != annotated.owner then
       report.error(i"TASTy annotation $annot added $sym with an inconsistent owner. Expected it to be owned by ${annotated.owner} but was owned by ${sym.owner}.", annot.tree)
+    else if annotated.isClass && annotated.owner.is(Package) /*&& !sym.isClass*/ then
+      report.error(i"TASTy annotation can not add top-level ${sym.showKind}. $annot tried to add $sym.", annot.tree)
     else
       sym.enteredAfter(thisPhase)
 

tests/neg-macros/annot-error-annot.check

@@ -1,68 +1,98 @@
 
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:18:6 ---------------------------------------------------------
-17 |  @error
-18 |  val vMember: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:17:6 ---------------------------------------------------------
+16 |@error
+17 |class cGlobal // error
+   |^
+   |MACRO ERROR
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:20:7 ---------------------------------------------------------
+19 |@error
+20 |object oGlobal // error
+   |^
+   |MACRO ERROR
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:24:6 ---------------------------------------------------------
+23 |  @error
+24 |  val vMember: Int = 1 // error
    |  ^
    |  MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:20:11 --------------------------------------------------------
-19 |  @error
-20 |  lazy val lvMember: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:26:11 --------------------------------------------------------
+25 |  @error
+26 |  lazy val lvMember: Int = 1 // error
    |  ^
    |  MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:22:6 ---------------------------------------------------------
-21 |  @error
-22 |  def dMember: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:28:6 ---------------------------------------------------------
+27 |  @error
+28 |  def dMember: Int = 1 // error
    |  ^
    |  MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:24:8 ---------------------------------------------------------
-23 |  @error
-24 |  given gMember: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:30:8 ---------------------------------------------------------
+29 |  @error
+30 |  given gMember: Int = 1 // error
    |  ^
    |  MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:26:8 ---------------------------------------------------------
-25 |  @error
-26 |  given gMember2: Num[Int] with // error: object not supported (TODO support)
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:32:8 ---------------------------------------------------------
+31 |  @error
+32 |  given gMember2: Num[Int] with // error
+   |  ^
+   |  MACRO ERROR
+33 |    def zero = 0
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:35:8 ---------------------------------------------------------
+34 |  @error
+35 |  given gMember3(using DummyImplicit): Num[Int] with // error
+   |  ^
+   |  MACRO ERROR
+36 |    def zero = 0
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:39:8 ---------------------------------------------------------
+38 |  @error
+39 |  class cMember // error
    |  ^
-   |  TASTy annotations are not supported on object
-27 |    def zero = 0
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:29:8 ---------------------------------------------------------
-28 |  @error
-29 |  given gMember3(using DummyImplicit): Num[Int] with // error: class not supported (TODO support)
+   |  MACRO ERROR
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:42:9 ---------------------------------------------------------
+41 |  @error
+42 |  object oMember // error
    |  ^
-   |  TASTy annotations are not supported on class
-30 |    def zero = 0
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:34:8 ---------------------------------------------------------
-33 |    @error
-34 |    val vLocal: Int = 1 // error
+   |  MACRO ERROR
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:46:8 ---------------------------------------------------------
+45 |    @error
+46 |    val vLocal: Int = 1 // error
    |    ^
    |    MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:36:13 --------------------------------------------------------
-35 |    @error
-36 |    lazy val lvLocal: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:48:13 --------------------------------------------------------
+47 |    @error
+48 |    lazy val lvLocal: Int = 1 // error
    |    ^
    |    MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:38:8 ---------------------------------------------------------
-37 |    @error
-38 |    def dLocal: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:50:8 ---------------------------------------------------------
+49 |    @error
+50 |    def dLocal: Int = 1 // error
    |    ^
    |    MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:40:10 --------------------------------------------------------
-39 |    @error
-40 |    given gLocal: Int = 1 // error
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:52:10 --------------------------------------------------------
+51 |    @error
+52 |    given gLocal: Int = 1 // error
    |    ^
    |    MACRO ERROR
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:42:10 --------------------------------------------------------
-41 |    @error
-42 |    given gLocal2: Num[Int] with // error: object not supported (TODO support)
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:54:10 --------------------------------------------------------
+53 |    @error
+54 |    given gLocal2: Num[Int] with // error
    |    ^
-   |    TASTy annotations are not supported on object
-43 |      def zero = 0
--- Error: tests/neg-macros/annot-error-annot/Test_2.scala:45:10 --------------------------------------------------------
-44 |    @error
-45 |    given gLocal3(using DummyImplicit): Num[Int] with // error: class not supported (TODO support)
+   |    MACRO ERROR
+55 |      def zero = 0
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:57:10 --------------------------------------------------------
+56 |    @error
+57 |    given gLocal3(using DummyImplicit): Num[Int] with // error
    |    ^
-   |    TASTy annotations are not supported on class
-46 |      def zero = 0
+   |    MACRO ERROR
+58 |      def zero = 0
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:61:10 --------------------------------------------------------
+60 |    @error
+61 |    class cLocal // error
+   |    ^
+   |    MACRO ERROR
+-- Error: tests/neg-macros/annot-error-annot/Test_2.scala:63:11 --------------------------------------------------------
+62 |    @error
+63 |    object oLocal // error
+   |    ^
+   |    MACRO ERROR
 -- Error: tests/neg-macros/annot-error-annot/Test_2.scala:2:4 ----------------------------------------------------------
 1 |@error
 2 |val vGlobal: Int = 1 // error
@@ -85,13 +115,13 @@
   |MACRO ERROR
 -- Error: tests/neg-macros/annot-error-annot/Test_2.scala:10:6 ---------------------------------------------------------
  9 |@error
-10 |given gGlobal2: Num[Int] with // error: object not supported (TODO support)
+10 |given gGlobal2: Num[Int] with // error
    |^
-   |TASTy annotations are not supported on object
+   |MACRO ERROR
 11 |  def zero = 0
 -- Error: tests/neg-macros/annot-error-annot/Test_2.scala:13:6 ---------------------------------------------------------
 12 |@error
-13 |given gGlobal3(using DummyImplicit): Num[Int] with // error: class not supported (TODO support)
+13 |given gGlobal3(using DummyImplicit): Num[Int] with // error
    |^
-   |TASTy annotations are not supported on class
+   |MACRO ERROR
 14 |  def zero = 0

tests/neg-macros/annot-error-annot/Test_2.scala

@@ -7,12 +7,18 @@ def dGlobal: Int = 1 // error
 @error
 given gGlobal: Int = 1 // error
 @error
-given gGlobal2: Num[Int] with // error: object not supported (TODO support)
+given gGlobal2: Num[Int] with // error
   def zero = 0
 @error
-given gGlobal3(using DummyImplicit): Num[Int] with // error: class not supported (TODO support)
+given gGlobal3(using DummyImplicit): Num[Int] with // error
   def zero = 0
 
+@error
+class cGlobal // error
+
+@error
+object oGlobal // error
+
 class B:
   @error
   val vMember: Int = 1 // error
@@ -23,12 +29,18 @@ class B:
   @error
   given gMember: Int = 1 // error
   @error
-  given gMember2: Num[Int] with // error: object not supported (TODO support)
+  given gMember2: Num[Int] with // error
     def zero = 0
   @error
-  given gMember3(using DummyImplicit): Num[Int] with // error: class not supported (TODO support)
+  given gMember3(using DummyImplicit): Num[Int] with // error
     def zero = 0
 
+  @error
+  class cMember // error
+
+  @error
+  object oMember // error
+
   def locals: Unit =
     @error
     val vLocal: Int = 1 // error
@@ -39,11 +51,16 @@ class B:
     @error
     given gLocal: Int = 1 // error
     @error
-    given gLocal2: Num[Int] with // error: object not supported (TODO support)
+    given gLocal2: Num[Int] with // error
       def zero = 0
     @error
-    given gLocal3(using DummyImplicit): Num[Int] with // error: class not supported (TODO support)
+    given gLocal3(using DummyImplicit): Num[Int] with // error
       def zero = 0
+
+    @error
+    class cLocal // error
+    @error
+    object oLocal // error
     ()
 
 trait Num[T]:

tests/neg-macros/annot-mod-class-add-top-method.check

@@ -0,0 +1,9 @@
+
+-- Error: tests/neg-macros/annot-mod-class-add-top-method/Test_2.scala:1:0 ---------------------------------------------
+1 |@addTopLevelMethod // error
+  |^^^^^^^^^^^^^^^^^^
+  |TASTy annotation can not add top-level method. @addTopLevelMethod tried to add method toLevelMethod$1.
+-- Error: tests/neg-macros/annot-mod-class-add-top-method/Test_2.scala:4:0 ---------------------------------------------
+4 |@addTopLevelMethod // error
+  |^^^^^^^^^^^^^^^^^^
+  |TASTy annotation can not add top-level method. @addTopLevelMethod tried to add method toLevelMethod$2.

tests/neg-macros/annot-mod-class-add-top-method/Macro_1.scala

@@ -0,0 +1,18 @@
+import scala.annotation.{experimental, TastyAnnotation}
+import scala.quoted._
+import scala.collection.mutable
+
+@experimental
+class addTopLevelMethod extends TastyAnnotation:
+  def transform(using Quotes)(tree: quotes.reflect.Definition): List[quotes.reflect.Definition] =
+    import quotes.reflect._
+    tree match
+      case ClassDef(name, ctr, parents, self, body) =>
+        val cls = tree.symbol
+        val methType = MethodType(Nil)(_ => Nil, _ => TypeRepr.of[Int])
+        val methSym = Symbol.newUniqueMethod(cls.owner, "toLevelMethod", methType, Flags.EmptyFlags, Symbol.noSymbol)
+        val methDef = DefDef(methSym, _ => Some(Literal(IntConstant(1))))
+        List(methDef, tree)
+      case _ =>
+        report.error("Annotation only supports `class`")
+        List(tree)

tests/neg-macros/annot-mod-class-add-top-method/Test_2.scala

@@ -0,0 +1,5 @@
+@addTopLevelMethod // error
+class Foo
+
+@addTopLevelMethod // error
+object Foo

tests/neg-macros/annot-mod-class-add-top-val.check

@@ -0,0 +1,9 @@
+
+-- Error: tests/neg-macros/annot-mod-class-add-top-val/Test_2.scala:1:0 ------------------------------------------------
+1 |@addTopLevelVal // error
+  |^^^^^^^^^^^^^^^
+  |TASTy annotation can not add top-level value. @addTopLevelVal tried to add value toLevelvalod$1.
+-- Error: tests/neg-macros/annot-mod-class-add-top-val/Test_2.scala:4:0 ------------------------------------------------
+4 |@addTopLevelVal // error
+  |^^^^^^^^^^^^^^^
+  |TASTy annotation can not add top-level value. @addTopLevelVal tried to add value toLevelvalod$2.

tests/neg-macros/annot-mod-class-add-top-val/Macro_1.scala

@@ -0,0 +1,17 @@
+import scala.annotation.{experimental, TastyAnnotation}
+import scala.quoted._
+import scala.collection.mutable
+
+@experimental
+class addTopLevelVal extends TastyAnnotation:
+  def transform(using Quotes)(tree: quotes.reflect.Definition): List[quotes.reflect.Definition] =
+    import quotes.reflect._
+    tree match
+      case ClassDef(name, ctr, parents, self, body) =>
+        val cls = tree.symbol
+        val valSym = Symbol.newUniqueVal(cls.owner, "toLevelvalod", TypeRepr.of[Int], Flags.EmptyFlags, Symbol.noSymbol)
+        val valDef = DefDef(valSym, _ => Some(Literal(IntConstant(1))))
+        List(valDef, tree)
+      case _ =>
+        report.error("Annotation only supports `class`")
+        List(tree)

tests/neg-macros/annot-mod-class-add-top-val/Test_2.scala

@@ -0,0 +1,5 @@
+@addTopLevelVal // error
+class Foo
+
+@addTopLevelVal // error
+object Foo