Adding warnings for selecting and assigning arrays

Author: EnzeXing

compiler/src/dotty/tools/dotc/transform/init/Objects.scala

@@ -798,6 +798,10 @@ object Objects:
       report.warning("[Internal error] unexpected tree in selecting a function, fun = " + fun.code.show + Trace.show, fun.code)
       Bottom
 
+    case arr: OfArray =>
+      report.warning("[Internal error] unexpected tree in selecting an array, array = " + arr.show + Trace.show, Trace.position)
+      Bottom
+
     case Bottom =>
       if field.isStaticObject then ObjectRef(field.moduleClass.asClass)
       else Bottom
@@ -818,6 +822,9 @@ object Objects:
     case fun: Fun =>
       report.warning("[Internal error] unexpected tree in assignment, fun = " + fun.code.show + Trace.show, Trace.position)
 
+    case arr: OfArray =>
+      report.warning("[Internal error] unexpected tree in assignment, array = " + arr.show + Trace.show, Trace.position)
+
     case Cold =>
       report.warning("Assigning to cold aliases is forbidden. Calling trace:\n" + Trace.show, Trace.position)
 
@@ -854,7 +861,7 @@ object Objects:
       report.warning("[Internal error] unexpected outer in instantiating a class, outer = " + outer.show + ", class = " + klass.show + ", " + Trace.show, Trace.position)
       Bottom
 
-    case _: Ref | _ : Cold.type | _ : Bottom.type =>
+    case outer: (Ref | Cold.type | Bottom.type) =>
       if klass == defn.ArrayClass then
         val arr = OfArray(State.currentObject, summon[Regions.Data])
         Heap.write(arr.addr, Bottom)
@@ -930,7 +937,7 @@ object Objects:
           case Cold =>
             report.warning("Calling cold by-name alias. Call trace: \n" + Trace.show, Trace.position)
             Bottom
-          case _: ValueSet | _: Ref =>
+          case _: ValueSet | _: Ref | _: OfArray =>
             report.warning("[Internal error] Unexpected by-name value " + value.show  + ". Calling trace:\n" + Trace.show, Trace.position)
             Bottom
         else

project/Build.scala

@@ -196,7 +196,7 @@ object Build {
       "-deprecation",
       "-unchecked",
       //"-Wconf:cat=deprecation&msg=Unsafe:s",    // example usage
-      // "-Xfatal-warnings",                         // -Werror in modern usage
+      "-Xfatal-warnings",                         // -Werror in modern usage
       "-encoding", "UTF8",
       "-language:implicitConversions",
     ),
@@ -810,9 +810,6 @@ object Build {
       )
     },
 
-    // Note: bench/profiles/projects.yml should be updated accordingly.
-    Compile / scalacOptions ++= Seq("-Yexplicit-nulls", "-Ysafe-init", "-Ysafe-init-global"),
-
     repl := (Compile / console).value,
     Compile / console / scalacOptions := Nil, // reset so that we get stock REPL behaviour!  E.g. avoid -unchecked being enabled
   )