Add error reporting

Author: liufengyun

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

@@ -140,7 +140,10 @@ object Checking {
 
   private def checkEffectsIn(effs: Effects, cls: ClassSymbol)(implicit state: State): Unit = {
     val rebased = Effects.asSeenFrom(effs, ThisRef(state.thisClass)(null), cls, Potentials.empty)
-    rebased.foreach { check(_) }
+    for {
+      eff <- rebased
+      error <- check(eff)
+    } error.report
   }
 
   private def check(eff: Effect)(implicit state: State): Errors =
@@ -162,8 +165,11 @@ object Checking {
 
             case Fun(pots, effs) =>
               val errs1 = effs.flatMap { check(_) }
-              val errs2 = pots.flatMap { pot => check(Promote(pot)(eff.source)) }
-              UnsafePromotion(pot, eff.source, state.path, errs1 ++ errs2).toErrors
+              val errs2 = pots.flatMap { pot => check(Promote(pot)(eff.source))(state.copy(path = Vector.empty)) }
+              if (errs1.nonEmpty || errs2.nonEmpty)
+                UnsafePromotion(pot, eff.source, state.path, errs1 ++ errs2).toErrors
+              else
+                Errors.empty
 
             case pot =>
               val pots = expand(pot)

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

@@ -7,6 +7,7 @@ import ast.tpd._
 import core._
 import Decorators._
 import Types._, Symbols._, Contexts._
+import util.NoSourcePosition
 
 import Effects._, Potentials._
 
@@ -18,13 +19,16 @@ object Errors {
     errs.map(_.show).mkString(", ")
 
   sealed trait Error {
+    def source: Tree
     def trace: Vector[Tree]
-    def report(implicit ctx: Context): Unit
     def show(implicit ctx: Context): String
 
+    def report(implicit ctx: Context): Unit =
+      ctx.warning(show + " Calling trace:\n" + stacktrace, source.sourcePos)
+
     def toErrors: Errors = Set(this)
 
-    def stacktrace(implicit ctx: Context): String = {
+    def stacktrace(implicit ctx: Context): String = if (trace.isEmpty) "" else " Calling trace:\n" + {
       var indentCount = 0
       var last = ""
       val sb = new StringBuilder
@@ -43,68 +47,68 @@ object Errors {
       }
       sb.toString
     }
+
+    /** Flatten UnsafePromotion errors
+     */
+    def flatten: Errors = this match {
+      case unsafe: UnsafePromotion => unsafe.errors.flatMap(_.flatten)
+      case _ => Set(this)
+    }
   }
 
   /** Access non-initialized field */
   case class AccessNonInit(field: Symbol, trace: Vector[Tree]) extends Error {
+    def source: Tree = trace.last
     def show(implicit ctx: Context): String =
-      "Access non-initialized field " + field.show + ". Calling trace:\n" + stacktrace
+      "Access non-initialized field " + field.show + "."
 
-    def report(implicit ctx: Context): Unit = ???
+    override def report(implicit ctx: Context): Unit = ctx.error(show + stacktrace, field.sourcePos)
   }
 
   /** Promote `this` under initialization to fully-initialized */
   case class PromoteThis(pot: ThisRef, source: Tree, trace: Vector[Tree]) extends Error {
-    def show(implicit ctx: Context): String = "Promote `this` to be initialized while it is not. Calling trace:\n" + stacktrace
-    def report(implicit ctx: Context): Unit = ???
+    def show(implicit ctx: Context): String = "Promote `this` to be initialized while it is not."
   }
 
   /** Promote `this` under initialization to fully-initialized */
   case class PromoteWarm(pot: Warm, source: Tree, trace: Vector[Tree]) extends Error {
     def show(implicit ctx: Context): String =
-      "Promoting the value under initialization to be initialized: " + source.show +
-      ". Calling trace:\n" + stacktrace
-
-    def report(implicit ctx: Context): Unit = ???
+      "Promoting the value under initialization to be initialized: " + source.show + "."
   }
 
   /** Promote a cold value under initialization to fully-initialized */
   case class PromoteCold(source: Tree, trace: Vector[Tree]) extends Error {
     def show(implicit ctx: Context): String =
-      "Promoting the value " + source.show + " to be initialized while it is under initialization" +
-      ". Calling trace:\n" + stacktrace
-
-    def report(implicit ctx: Context): Unit = ???
+      "Promoting the value " + source.show + " to be initialized while it is under initialization" + "."
   }
 
   case class AccessCold(field: Symbol, source: Tree, trace: Vector[Tree]) extends Error {
     def show(implicit ctx: Context): String =
-      "Access field " + source.show + " on a value under unknown initialization status" +
-      ". Calling trace:\n" + stacktrace
-
-    def report(implicit ctx: Context): Unit = ???
+      "Access field " + source.show + " on a value under unknown initialization status" + "."
   }
 
   case class CallCold(meth: Symbol, source: Tree, trace: Vector[Tree]) extends Error {
     def show(implicit ctx: Context): String =
-      "Call method " + source.show + " on a value under unknown initialization" +
-      ". Calling trace:\n" + stacktrace
-
-    def report(implicit ctx: Context): Unit = ???
+      "Call method " + source.show + " on a value under unknown initialization" + "."
   }
 
   case class CallUnknown(meth: Symbol, source: Tree, trace: Vector[Tree]) extends Error {
     def show(implicit ctx: Context): String =
-      "Calling the external method " + meth.show +
-      " may cause initialization errors" + ". Calling trace:\n" + stacktrace
-
-    def report(implicit ctx: Context): Unit = ???
+      "Calling the external method " + meth.show + " may cause initialization errors" + "."
   }
 
   /** Promote a value under initialization to fully-initialized */
-  case class UnsafePromotion(pot: Potential, source: Tree, trace: Vector[Tree], errors: Set[Error]) extends Error {
-    def show(implicit ctx: Context): String = ???
-
-    def report(implicit ctx: Context): Unit = ???
+  case class UnsafePromotion(pot: Potential, source: Tree, trace: Vector[Tree], errors: Errors) extends Error {
+    assert(errors.nonEmpty)
+
+    def show(implicit ctx: Context): String = {
+      var index = 0
+      "Promoting the value " + source.show + " to initialized is unsafe.\n" + stacktrace +
+        "\n The unsafe promotion is caused by the following problem(s):" +
+        errors.map { error =>
+          index += 1
+          s"\n  $index" + error.show + error.stacktrace
+        }.mkString
+    }
   }
 }