New config setting: noUnsafeMutableFields

Author: odersky

compiler/src/dotty/tools/dotc/cc/CheckCaptures.scala

@@ -1141,7 +1141,7 @@ class CheckCaptures extends Recheck, SymTransformer:
                   ""
               disallowBadRootsIn(
                 tree.tpt.nuType, NoSymbol, i"Mutable $sym", "have type", addendum, sym.srcPos)
-            if sepChecksEnabled && false
+            if ccConfig.noUnsafeMutableFields
                 && sym.owner.isClass
                 && !sym.owner.derivesFrom(defn.Caps_Mutable)
                 && !sym.hasAnnotation(defn.UntrackedCapturesAnnot) then

compiler/src/dotty/tools/dotc/cc/ccConfig.scala

@@ -48,6 +48,11 @@ object ccConfig:
    */
   inline val useSpanCapset = false
 
+  /** If true force all mutable fields to be in Mutable classes, unless they
+   *  are annotated with @untrackedCaptures
+   */
+  inline val noUnsafeMutableFields = false
+
   /** If true, do level checking for FreshCap instances */
   def useFreshLevels(using Context): Boolean =
     Feature.sourceVersion.stable.isAtLeast(SourceVersion.`3.7`)
@@ -59,4 +64,6 @@ object ccConfig:
   def allowUse(using Context): Boolean =
     Feature.sourceVersion.stable.isAtMost(SourceVersion.`3.7`)
 
+
+
 end ccConfig