Add tests to check for wrong owner

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

@@ -143,10 +143,10 @@ class MacroAnnotations(phase: IdentityDenotTransformer):
         val isSymbolInDecls = tdef.symbol.asClass.info.decls.toList.toSet
         for tree <- template.body do
           if tree.symbol.owner != tdef.symbol then
-            report.error(em"Macro added a definition with the wrong owner - ${tree.symbol.owner} - ${tdef.symbol} in ${tree.source}")
+            report.error(em"Macro added a definition with the wrong owner - ${tree.symbol.owner} - ${tdef.symbol} in ${tree.source}", tree.srcPos)
           else if !isSymbolInDecls(tree.symbol) then
             tree.symbol.enteredAfter(phase)
-        traverseChildren(tree) // Taverse before or after dealing with this class?
+        traverseChildren(tree)
       case _ => traverseChildren(tree)
   }.traverse(tree)
 

tests/neg-macros/wrong-owner.check

@@ -0,0 +1,23 @@
+-- Error: tests/neg-macros/wrong-owner/Test_2.scala:7:6 ------------------------
+5 |@experimental
+6 |@wrongOwner
+7 |class Foo // error
+  |^
+  |Malformed tree was found while expanding macro with -Xcheck-macros.
+  |               |The tree does not conform to the compiler's tree invariants.
+  |               |
+  |               |Macro was:
+  |               |@scala.annotation.internal.SourceFile("tests/neg-macros/wrong-owner/Test_2.scala") @wrongOwner @scala.annotation.experimental class Foo()
+  |               |
+  |               |The macro returned:
+  |               |@scala.annotation.internal.SourceFile("tests/neg-macros/wrong-owner/Test_2.scala") @wrongOwner @scala.annotation.experimental class Foo() {
+  |  override def toString(): java.lang.String = "Hello from macro"
+  |}
+  |               |
+  |               |Error:
+  |               |assertion failed: bad owner; method toString has owner class String, expected was class Foo
+  |owner chain = method toString, class String, package java.lang, package java, package <root>, ctxOwners = class Foo, class Foo, package <empty>, package <empty>, package <empty>, package <root>, package <root>, package <root>, package <root>, package <root>, package <root>,  <none>,  <none>,  <none>,  <none>
+  |               |
+  |stacktrace available when compiling with `-Ydebug`
+  |               |
+1 error found

tests/neg-macros/wrong-owner/Macro_1.scala

@@ -0,0 +1,19 @@
+import scala.annotation.experimental
+import scala.annotation.MacroAnnotation
+import scala.quoted.*
+
+@experimental
+class wrongOwner 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(Symbol.classSymbol("java.lang.String"), "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-macros/wrong-owner/Test_2.scala

@@ -0,0 +1,5 @@
+import scala.annotation.experimental
+
+@experimental
+@wrongOwner
+class Foo // error