Try early promotion before updating env

Author: EnzeXing

compiler/src/dotty/tools/dotc/config/Config.scala

@@ -192,7 +192,7 @@ object Config {
   inline val flattenContextFunctionResults = true
 
   /** If set, enables tracing */
-  inline val tracingEnabled = true
+  inline val tracingEnabled = false
 
   /** Initial capacity of the uniques HashMap.
    *  Note: This should be a power of two to work with util.HashSet

compiler/src/dotty/tools/dotc/config/Printers.scala

@@ -28,7 +28,7 @@ object Printers {
   val implicits = noPrinter
   val implicitsDetailed = noPrinter
   val lexical = noPrinter
-  val init = new Printer
+  val init = noPrinter
   val inlining = noPrinter
   val interactiv = noPrinter
   val matchTypes = noPrinter

compiler/src/dotty/tools/dotc/reporting/trace.scala

@@ -90,7 +90,7 @@ trait TraceSyntax:
           finalize(trailing(ex.value))
           throw ex
         case ex: Throwable =>
-          // val msg = s"<== $q = <missing> (with exception $ex)"
-          // finalize(msg)
+          val msg = s"<== $q = <missing> (with exception $ex)"
+          finalize(msg)
           throw ex
 end TraceSyntax

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

@@ -690,7 +690,8 @@ class Semantic {
     case h :: t => h match {
       case v: ValDef => {
         val res = eval(h, thisV, klass)
-        val newEnv = Env(Map(v.symbol -> res.value))
+        val newEnv = 
+          if res.value.promote("Try early promotion", h).isEmpty then Env(Map(v.symbol -> Hot)) else Env(Map(v.symbol -> res.value))
         withEnv(env.union(newEnv)) {
           val (res2, env2) = eval(t, thisV, klass)
           (res :: res2, env2)