Fix tracked modifier checks

Author: KacperFKorban

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

@@ -1484,7 +1484,7 @@ object desugar {
   val legalTracked: Context ?=> MemberDefTest = {
     case valdef @ ValDef(_, _, _) =>
       val sym = valdef.symbol
-      ctx.owner.exists && (ctx.owner.isClass || ctx.owner.isConstructor)
+      !ctx.owner.exists || ctx.owner.isClass || ctx.owner.is(Case) || ctx.owner.isConstructor || valdef.mods.is(Param) || valdef.mods.is(ParamAccessor)
   }
 
   def checkOpaqueAlias(tree: MemberDef)(using Context): MemberDef =

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2835,14 +2835,14 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
         excludeDeferredGiven(rhs, sym):
           typedExpr(_, tpt1.tpe.widenExpr)
     setAbstractTrackedInfo(sym, rhs1, tpt)
-    val tpt2 = if sym.flags.is(Tracked) && tpt.isEmpty && !sym.flags.is(ParamAccessor) then TypeTree(rhs1.tpe) else tpt1
+    val tpt2 = if sym.flags.is(Tracked) && tpt.isEmpty && !sym.flags.is(ParamAccessor) && !sym.flags.is(Param) then TypeTree(rhs1.tpe) else tpt1
     val vdef2 = assignType(cpy.ValDef(vdef)(name, tpt2, rhs1), sym)
     postProcessInfo(vdef2, sym)
     vdef2.setDefTree
   }
 
   private def setAbstractTrackedInfo(sym: Symbol, rhs: Tree, tpt: untpd.Tree)(using Context): Unit =
-    if sym.allOverriddenSymbols.exists(_.flags.is(Tracked)) && !sym.flags.is(ParamAccessor) then
+    if sym.allOverriddenSymbols.exists(_.flags.is(Tracked)) && !sym.flags.is(ParamAccessor) && !sym.flags.is(Param) then
       sym.setFlag(Tracked)
       if tpt.isEmpty then
         sym.info = rhs.tpe

tests/neg/tracked.check

@@ -6,22 +6,6 @@
 7 |  def foo(tracked a: Int) = // error
   |                  ^
   |                  ':' expected, but identifier found
--- Error: tests/neg/tracked.scala:8:12 ---------------------------------------------------------------------------------
-8 |    tracked val b: Int = 2 // error
-  |            ^^^
-  |            end of statement expected but 'val' found
--- Error: tests/neg/tracked.scala:11:10 --------------------------------------------------------------------------------
-11 |  tracked object Foo // error // error
-   |          ^^^^^^
-   |          end of statement expected but 'object' found
--- Error: tests/neg/tracked.scala:14:10 --------------------------------------------------------------------------------
-14 |  tracked class D // error // error
-   |          ^^^^^
-   |          end of statement expected but 'class' found
--- Error: tests/neg/tracked.scala:17:10 --------------------------------------------------------------------------------
-17 |  tracked type T = Int // error // error
-   |          ^^^^
-   |          end of statement expected but 'type' found
 -- Error: tests/neg/tracked.scala:20:25 --------------------------------------------------------------------------------
 20 |  given g2: (tracked val x: Int) => C = C(x) // error
    |             ^^^^^^^^^^^^^^^^^^
@@ -30,21 +14,19 @@
 4 |class C2(tracked var x: Int) // error
   |                     ^
   |                     mutable variables may not be `tracked`
--- [E006] Not Found Error: tests/neg/tracked.scala:11:2 ----------------------------------------------------------------
-11 |  tracked object Foo // error // error
-   |  ^^^^^^^
-   |  Not found: tracked
-   |
-   | longer explanation available when compiling with `-explain`
--- [E006] Not Found Error: tests/neg/tracked.scala:14:2 ----------------------------------------------------------------
-14 |  tracked class D // error // error
-   |  ^^^^^^^
-   |  Not found: tracked
-   |
-   | longer explanation available when compiling with `-explain`
--- [E006] Not Found Error: tests/neg/tracked.scala:17:2 ----------------------------------------------------------------
-17 |  tracked type T = Int // error // error
-   |  ^^^^^^^
-   |  Not found: tracked
-   |
-   | longer explanation available when compiling with `-explain`
+-- [E156] Syntax Error: tests/neg/tracked.scala:8:16 -------------------------------------------------------------------
+8 |    tracked val b: Int = 2 // error
+  |    ^^^^^^^^^^^^^^^^^^^^^^
+  |    Modifier tracked is not allowed for this definition
+-- [E156] Syntax Error: tests/neg/tracked.scala:11:17 ------------------------------------------------------------------
+11 |  tracked object Foo // error
+   |  ^^^^^^^^^^^^^^^^^^
+   |  Modifier tracked is not allowed for this definition
+-- [E156] Syntax Error: tests/neg/tracked.scala:14:16 ------------------------------------------------------------------
+14 |  tracked class D // error
+   |  ^^^^^^^^^^^^^^^
+   |  Modifier tracked is not allowed for this definition
+-- [E156] Syntax Error: tests/neg/tracked.scala:17:15 ------------------------------------------------------------------
+17 |  tracked type T = Int // error
+   |  ^^^^^^^^^^^^^^^^^^^^
+   |  Modifier tracked is not allowed for this definition

tests/neg/tracked.scala

@@ -8,13 +8,13 @@ object A:
     tracked val b: Int = 2 // error
 
 object B:
-  tracked object Foo // error // error
+  tracked object Foo // error
 
 object C:
-  tracked class D // error // error
+  tracked class D // error
 
 object D:
-  tracked type T = Int // error // error
+  tracked type T = Int // error
 
 object E:
   given g2: (tracked val x: Int) => C = C(x) // error