Merge pull request #15682 from dotty-staging/zero-init-warnings

Fix remaining initialization warnings in bootstrapping

Author: olhotak

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

@@ -6,107 +6,119 @@ package init
 import ast.tpd._
 import core._
 import util.SourcePosition
+import util.Property
 import Decorators._, printing.SyntaxHighlighting
 import Types._, Symbols._, Contexts._
 
 import scala.collection.mutable
 
 object Errors:
+  private val IsFromPromotion = new Property.Key[Boolean]
+
   sealed trait Error:
     def trace: Seq[Tree]
     def show(using Context): String
 
     def pos(using Context): SourcePosition = trace.last.sourcePos
 
+    def stacktrace(using Context): String =
+      val preamble: String =
+        if ctx.property(IsFromPromotion).nonEmpty
+        then " Promotion trace:\n"
+        else " Calling trace:\n"
+      buildStacktrace(trace, preamble)
+
     def issue(using Context): Unit =
       report.warning(show, this.pos)
+  end Error
+
+  def buildStacktrace(trace: Seq[Tree], preamble: String)(using Context): String = if trace.isEmpty then "" else preamble + {
+    var lastLineNum = -1
+    var lines: mutable.ArrayBuffer[String] = new mutable.ArrayBuffer
+    trace.foreach { tree =>
+      val pos = tree.sourcePos
+      val prefix = "-> "
+      val line =
+        if pos.source.exists then
+          val loc = "[ " + pos.source.file.name + ":" + (pos.line + 1) + " ]"
+          val code = SyntaxHighlighting.highlight(pos.lineContent.trim.nn)
+          i"$code\t$loc"
+        else
+          tree.show
+      val positionMarkerLine =
+        if pos.exists && pos.source.exists then
+          positionMarker(pos)
+        else ""
+
+      // always use the more precise trace location
+      if lastLineNum == pos.line then
+        lines.dropRightInPlace(1)
 
-    def stacktrace(preamble: String = " Calling trace:\n")(using Context): String = if trace.isEmpty then "" else preamble + {
-      var lastLineNum = -1
-      var lines: mutable.ArrayBuffer[String] = new mutable.ArrayBuffer
-      trace.foreach { tree =>
-        val pos = tree.sourcePos
-        val prefix = "-> "
-        val line =
-          if pos.source.exists then
-            val loc = "[ " + pos.source.file.name + ":" + (pos.line + 1) + " ]"
-            val code = SyntaxHighlighting.highlight(pos.lineContent.trim.nn)
-            i"$code\t$loc"
-          else
-            tree.show
-        val positionMarkerLine =
-          if pos.exists && pos.source.exists then
-            positionMarker(pos)
-          else ""
-
-        // always use the more precise trace location
-        if lastLineNum == pos.line then
-          lines.dropRightInPlace(1)
-
-        lines += (prefix + line + "\n" + positionMarkerLine)
-
-        lastLineNum = pos.line
-      }
-      val sb = new StringBuilder
-      for line <- lines do sb.append(line)
-      sb.toString
+      lines += (prefix + line + "\n" + positionMarkerLine)
+
+      lastLineNum = pos.line
     }
+    val sb = new StringBuilder
+    for line <- lines do sb.append(line)
+    sb.toString
+  }
 
-    /** Used to underline source positions in the stack trace
-     *  pos.source must exist
-     */
-    private def positionMarker(pos: SourcePosition): String =
-      val trimmed = pos.lineContent.takeWhile(c => c.isWhitespace).length
-      val padding = pos.startColumnPadding.substring(trimmed).nn + "   "
-      val carets =
-        if (pos.startLine == pos.endLine)
-          "^" * math.max(1, pos.endColumn - pos.startColumn)
-        else "^"
+  /** Used to underline source positions in the stack trace
+   *  pos.source must exist
+   */
+  private def positionMarker(pos: SourcePosition): String =
+    val trimmed = pos.lineContent.takeWhile(c => c.isWhitespace).length
+    val padding = pos.startColumnPadding.substring(trimmed).nn + "   "
+    val carets =
+      if (pos.startLine == pos.endLine)
+        "^" * math.max(1, pos.endColumn - pos.startColumn)
+      else "^"
 
-      s"$padding$carets\n"
+    s"$padding$carets\n"
 
-    override def toString() = this.getClass.getName.nn
-  end Error
+  override def toString() = this.getClass.getName.nn
 
   /** Access non-initialized field */
   case class AccessNonInit(field: Symbol, trace: Seq[Tree]) extends Error:
     def source: Tree = trace.last
     def show(using Context): String =
-      "Access non-initialized " + field.show + "." + stacktrace()
+      "Access non-initialized " + field.show + "." + stacktrace
 
     override def pos(using Context): SourcePosition = field.sourcePos
 
   /** Promote a value under initialization to fully-initialized */
   case class PromoteError(msg: String, trace: Seq[Tree]) extends Error:
-    def show(using Context): String = msg + stacktrace()
+    def show(using Context): String = msg + stacktrace
 
   case class AccessCold(field: Symbol, trace: Seq[Tree]) extends Error:
     def show(using Context): String =
-      "Access field " + field.show +  " on a cold object." + stacktrace()
+      "Access field " + field.show +  " on a cold object." + stacktrace
 
   case class CallCold(meth: Symbol, trace: Seq[Tree]) extends Error:
     def show(using Context): String =
-      "Call method " + meth.show + " on a cold object." + stacktrace()
+      "Call method " + meth.show + " on a cold object." + stacktrace
 
   case class CallUnknown(meth: Symbol, trace: Seq[Tree]) extends Error:
     def show(using Context): String =
       val prefix = if meth.is(Flags.Method) then "Calling the external method " else "Accessing the external field"
-      prefix + meth.show + " may cause initialization errors." + stacktrace()
+      prefix + meth.show + " may cause initialization errors." + stacktrace
 
   /** Promote a value under initialization to fully-initialized */
   case class UnsafePromotion(msg: String, trace: Seq[Tree], error: Error) extends Error:
     def show(using Context): String =
-      msg + stacktrace() + "\n" +
-        "Promoting the value to fully initialized failed due to the following problem:\n" +
-        error.show
+      msg + stacktrace + "\n" +
+        "Promoting the value to hot failed due to the following problem:\n" + {
+          val ctx2 = ctx.withProperty(IsFromPromotion, Some(true))
+          error.show(using ctx2)
+        }
 
   /** Unsafe leaking a non-hot value as constructor arguments
    *
    *  Invariant: argsIndices.nonEmpty
    */
   case class UnsafeLeaking(trace: Seq[Tree], error: Error, nonHotOuterClass: Symbol, argsIndices: List[Int]) extends Error:
     def show(using Context): String =
-      "Problematic object instantiation: " + argumentInfo() + stacktrace() + "\n" +
+      "Problematic object instantiation: " + argumentInfo() + stacktrace + "\n" +
         "It leads to the following error during object initialization:\n" +
         error.show
 
@@ -129,5 +141,5 @@ object Errors:
           acc + text2
         }
       val verb = if multiple then " are " else " is "
-      val adjective = "not fully initialized."
+      val adjective = "not hot."
       subject + verb + adjective