Add MiniPhase to enter generated symbols from MacroAnnotations

Author: hamzaremmal

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -7,7 +7,6 @@ import typer.{TyperPhase, RefChecks}
 import parsing.Parser
 import Phases.Phase
 import transform._
-import dotty.tools.backend
 import backend.jvm.{CollectSuperCalls, GenBCode}
 import localopt.StringInterpolatorOpt
 
@@ -49,6 +48,7 @@ class Compiler {
   protected def picklerPhases: List[List[Phase]] =
     List(new Pickler) ::            // Generate TASTY info
     List(new Inlining) ::           // Inline and execute macros
+    List(new PostInlining2) ::       // Add mirror support for inlined code
     List(new PostInlining) ::       // Add mirror support for inlined code
     List(new CheckUnused.PostInlining) ::  // Check for unused elements
     List(new Staging) ::            // Check staging levels and heal staged types

compiler/src/dotty/tools/dotc/transform/PostInlining2.scala

@@ -0,0 +1,52 @@
+package dotty.tools.dotc
+package transform
+
+import core.*
+import ast.tpd.*
+import Contexts.*
+import dotty.tools.dotc.core.DenotTransformers.IdentityDenotTransformer
+
+/**
+ * ???
+ * @author Hamza REMMAL ([email protected])
+ */
+class PostInlining2 extends MacroTransform, IdentityDenotTransformer:
+  thisPhase =>
+
+  override def phaseName: String = PostInlining2.name
+
+  override def description: String = PostInlining2.description
+
+  override def changesMembers = true
+
+  def newTransformer(using Context): Transformer = new Transformer:
+    override def transform(tree: Tree)(using Context): Tree =
+      super.transform(tree) match
+        // HR : Check if the owner of the added symbols is correct.
+        // HR : if yes, and the symbol is not entered. enter it
+
+        /* HR : Questions :
+            - What symbol are we allowed to change ? Check for now if the content of the tree is consistent
+            - What happens if we enter a symbol twice ? I have a NamingError reported
+            - What if we already have that symbol entered ? ignore it...
+            - Can we merge it with the PostInlining phase ?
+            - Is there an optimal way to check if a tree was generated by a macro annotation ?
+            - Define a correct error message below
+         */
+
+        case t@TypeDef(_, template: Template) =>
+          for tree <- template.constr :: template.body do
+            if tree.symbol.owner == t.symbol then
+              if !t.symbol.asClass.info.decls.exists(_ == tree.symbol) then
+                tree.symbol.enteredAfter(thisPhase)
+            else
+              report.error("Macro added a definition with the wrong owner")
+          t
+        case t => t
+
+
+
+object PostInlining2:
+      val name: String = "postInlining2"
+      val description: String = "check the result of the macro annotation extension"
+

tests/neg/i18825.check

@@ -0,0 +1,3 @@
+error overriding method toString in class Foo of type (): String;
+  method toString of type (): String cannot override final member method toString in class Foo
+1 error found

tests/neg/i18825/Macro_1.scala

@@ -0,0 +1,19 @@
+import scala.annotation.experimental
+import scala.annotation.MacroAnnotation
+import scala.quoted.*
+
+@experimental
+class toString extends MacroAnnotation :
+  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 toStringSym = Symbol.requiredMethod("java.lang.Object.toString")
+        val toStringOverrideSym = Symbol.newMethod(cls, "toString", toStringSym.info, Flags.Override, Symbol.noSymbol)
+        val toStringDef = DefDef(toStringOverrideSym, _ => Some(Literal(StringConstant("Hello from macro"))))
+        val newClassDef = ClassDef.copy(tree)(name, ctr, parents, self, toStringDef :: body)
+        List(newClassDef)
+      case _ =>
+        report.error("@toString can only be annotated on class definitions")
+        tree :: Nil

tests/neg/i18825/Test_2.scala

@@ -0,0 +1,13 @@
+import annotation.experimental
+
+class Foo :
+  final override def toString(): String = "Hello"
+
+@experimental
+@toString
+class AFoo extends Foo //:
+  //override def toString(): String = "Hello from macro"
+
+@experimental
+@main def run =
+  println(new AFoo().toString)