Optimize and simplify SourcePosition handling

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -533,7 +533,7 @@ object desugar {
         appliedRef(enumClassRef)
       else {
         report.error(TypedCaseDoesNotExplicitlyExtendTypedEnum(enumClass, cdef)
-            , cdef.sourcePos.startPos)
+            , cdef.srcPos.startPos)
         appliedTypeTree(enumClassRef, constrTparams map (_ => anyRef))
       }
 
@@ -633,7 +633,7 @@ object desugar {
         .withSpan(cdef.span).toList
       if (companionDerived.nonEmpty)
         for (modClsDef @ TypeDef(_, _) <- mdefs)
-          modClsDef.putAttachment(DerivingCompanion, impl.sourcePos.startPos)
+          modClsDef.putAttachment(DerivingCompanion, impl.srcPos.startPos)
       mdefs
     }
 
@@ -741,19 +741,19 @@ object desugar {
       if (!mods.isOneOf(GivenOrImplicit))
         Nil
       else if (ctx.owner.is(Package)) {
-        report.error(TopLevelImplicitClass(cdef), cdef.sourcePos)
+        report.error(TopLevelImplicitClass(cdef), cdef.srcPos)
         Nil
       }
       else if (mods.is(Trait)) {
-        report.error(TypesAndTraitsCantBeImplicit(), cdef.sourcePos)
+        report.error(TypesAndTraitsCantBeImplicit(), cdef.srcPos)
         Nil
       }
       else if (isCaseClass) {
-        report.error(ImplicitCaseClass(cdef), cdef.sourcePos)
+        report.error(ImplicitCaseClass(cdef), cdef.srcPos)
         Nil
       }
       else if (arity != 1 && !mods.is(Given)) {
-        report.error(ImplicitClassPrimaryConstructorArity(), cdef.sourcePos)
+        report.error(ImplicitClassPrimaryConstructorArity(), cdef.srcPos)
         Nil
       }
       else {
@@ -895,7 +895,7 @@ object desugar {
         .withSpan(mdef.span.startPos)
       val ValDef(selfName, selfTpt, _) = impl.self
       val selfMods = impl.self.mods
-      if (!selfTpt.isEmpty) report.error(ObjectMayNotHaveSelfType(mdef), impl.self.sourcePos)
+      if (!selfTpt.isEmpty) report.error(ObjectMayNotHaveSelfType(mdef), impl.self.srcPos)
       val clsSelf = ValDef(selfName, SingletonTypeTree(Ident(moduleName)), impl.self.rhs)
         .withMods(selfMods)
         .withSpan(impl.self.span.orElse(impl.span.startPos))
@@ -911,7 +911,7 @@ object desugar {
     for mdef <- ext.methods yield
       if mdef.tparams.nonEmpty then
         report.error("extension method cannot have type parameters here, all type parameters go after `extension`",
-          mdef.tparams.head.sourcePos)
+          mdef.tparams.head.srcPos)
       defDef(
         cpy.DefDef(mdef)(
           name = mdef.name.toExtensionName,
@@ -1015,7 +1015,7 @@ object desugar {
             case Some(DefDef(name, _, (vparam :: _) :: _, _, _)) =>
               s"extension_${name}_${inventTypeName(vparam.tpt)}"
             case _ =>
-              report.error(AnonymousInstanceCannotBeEmpty(impl), impl.sourcePos)
+              report.error(AnonymousInstanceCannotBeEmpty(impl), impl.srcPos)
               nme.ERROR.toString
         else
           impl.parents.map(inventTypeName(_)).mkString("given_", "_", "")
@@ -1189,7 +1189,7 @@ object desugar {
       var tested: MemberDef = tree
       def checkApplicable(flag: Flag, test: MemberDefTest): Unit =
         if (tested.mods.is(flag) && !test.applyOrElse(tree, (md: MemberDef) => false)) {
-          report.error(ModifierNotAllowedForDefinition(flag), tree.sourcePos)
+          report.error(ModifierNotAllowedForDefinition(flag), tree.srcPos)
           tested = tested.withMods(tested.mods.withoutFlags(flag))
         }
       checkApplicable(Opaque, legalOpaque)
@@ -1701,7 +1701,7 @@ object desugar {
                  |This can be achieved by adding the import clause 'import scala.language.postfixOps'
                  |or by setting the compiler option -language:postfixOps.
                  |See the Scaladoc for value scala.language.postfixOps for a discussion
-                 |why the feature needs to be explicitly enabled.""".stripMargin, t.sourcePos)
+                 |why the feature needs to be explicitly enabled.""".stripMargin, t.srcPos)
           }
           Select(t, op.name)
         }
@@ -1821,7 +1821,7 @@ object desugar {
         elems foreach collect
       case Alternative(trees) =>
         for (tree <- trees; (vble, _) <- getVariables(tree))
-          report.error(IllegalVariableInPatternAlternative(), vble.sourcePos)
+          report.error(IllegalVariableInPatternAlternative(), vble.srcPos)
       case Annotated(arg, _) =>
         collect(arg)
       case InterpolatedString(_, segments) =>
@@ -1844,7 +1844,7 @@ object desugar {
           def traverse(tree: untpd.Tree)(using Context): Unit = tree match {
             case Splice(expr) => collect(expr)
             case TypSplice(expr) =>
-              report.error(TypeSpliceInValPattern(expr), tree.sourcePos)
+              report.error(TypeSpliceInValPattern(expr), tree.srcPos)
             case _ => traverseChildren(tree)
           }
         }.traverse(expr)

compiler/src/dotty/tools/dotc/ast/DesugarEnums.scala

@@ -217,7 +217,7 @@ object DesugarEnums {
           case Ident(name) =>
             val matches = tparamNames.contains(name)
             if (matches && (caseTypeParams.nonEmpty || vparamss.isEmpty))
-              report.error(i"illegal reference to type parameter $name from enum case", tree.sourcePos)
+              report.error(i"illegal reference to type parameter $name from enum case", tree.srcPos)
             matches
           case LambdaTypeTree(lambdaParams, body) =>
             underBinders(lambdaParams, foldOver(x, tree))

compiler/src/dotty/tools/dotc/ast/Positioned.scala

@@ -3,7 +3,7 @@ package dotc
 package ast
 
 import util.Spans._
-import util.{SourceFile, NoSource, SourcePosition}
+import util.{SourceFile, NoSource, SourcePosition, SrcPos}
 import core.Contexts._
 import core.Decorators._
 import core.Flags.{JavaDefined, Extension}
@@ -17,7 +17,7 @@ import java.io.{ PrintWriter }
 
 /** A base class for things that have positions (currently: modifiers and trees)
  */
-abstract class Positioned(implicit @constructorOnly src: SourceFile) extends Product with Cloneable {
+abstract class Positioned(implicit @constructorOnly src: SourceFile) extends SrcPos, Product, Cloneable {
 
   private var myUniqueId: Int = _
   private var mySpan: Span = _
@@ -46,7 +46,12 @@ abstract class Positioned(implicit @constructorOnly src: SourceFile) extends Pro
   span = envelope(src)
 
   def source: SourceFile = SourceFile.fromId(uniqueId)
-  def sourcePos: SourcePosition = source.atSpan(span)
+  def sourcePos(using Context): SourcePosition = source.atSpan(span)
+
+  /** This positioned item, widened to `SrcPos`. Used to make clear we only need the
+   *  position, typically for error reporting.
+   */
+  final def srcPos: SrcPos = this
 
   /** A positioned item like this one with given `span`.
    *  If the positioned item is source-derived, a clone is returned.

compiler/src/dotty/tools/dotc/ast/TreeMapWithImplicits.scala

@@ -121,7 +121,7 @@ class TreeMapWithImplicits extends tpd.TreeMap {
     }
     catch {
       case ex: TypeError =>
-        report.error(ex, tree.sourcePos)
+        report.error(ex, tree.srcPos)
         tree
     }
   }

compiler/src/dotty/tools/dotc/ast/Trees.scala

@@ -10,7 +10,7 @@ import language.higherKinds
 import collection.mutable.ListBuffer
 import printing.Printer
 import printing.Texts.Text
-import util.{Stats, Attachment, Property, SourceFile, NoSource, SourcePosition}
+import util.{Stats, Attachment, Property, SourceFile, NoSource, SrcPos, SourcePosition}
 import config.Config
 import annotation.internal.sharable
 import annotation.unchecked.uncheckedVariance
@@ -54,18 +54,10 @@ object Trees {
    *     nodes.
    */
   abstract class Tree[-T >: Untyped](implicit @constructorOnly src: SourceFile)
-  extends Positioned
-     with Product
-     with Attachment.Container
-     with printing.Showable {
+  extends Positioned, SrcPos, Product, Attachment.Container, printing.Showable {
 
     if (Stats.enabled) ntrees += 1
 
-    /** This tree, widened to `Positioned`. Used to make clear we only need the
-     *  position, typically for error reporting.
-     */
-    final def posd: Positioned = this
-
     /** The type  constructor at the root of the tree */
     type ThisTree[T >: Untyped] <: Tree[T]
 

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

@@ -6,7 +6,7 @@ import core._
 import Contexts._, Symbols._, Names._, NameOps._, Phases._
 import StdNames.nme
 import Decorators.{given _}
-import util.SourcePosition
+import util.SrcPos
 import SourceVersion._
 import reporting.Message
 
@@ -76,7 +76,7 @@ object Feature:
   /** If current source migrates to `version`, issue given warning message
    *  and return `true`, otherwise return `false`.
    */
-  def warnOnMigration(msg: Message, pos: SourcePosition,
+  def warnOnMigration(msg: Message, pos: SrcPos,
       version: SourceVersion = defaultSourceVersion)(using Context): Boolean =
     if sourceVersion.isMigrating && sourceVersion.stable == version
        || version == `3.0` && migrateTo3

compiler/src/dotty/tools/dotc/core/Decorators.scala

@@ -5,7 +5,7 @@ package core
 import annotation.tailrec
 import Symbols._
 import Contexts._, Names._, Phases._, printing.Texts._, printing.Printer
-import util.Spans.Span, util.SourcePosition
+import util.Spans.Span
 import collection.mutable.ListBuffer
 import dotty.tools.dotc.transform.MegaPhase
 import ast.tpd._

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -2508,7 +2508,7 @@ object SymDenotations {
     def complete(denot: SymDenotation)(using Context): Unit = {
       val sym = denot.symbol
       val errMsg = BadSymbolicReference(denot)
-      report.error(errMsg, sym.sourcePos)
+      report.error(errMsg, sym.srcPos)
       if (ctx.debug) throw new scala.Error()
       initializeToDefaults(denot, errMsg)
     }

compiler/src/dotty/tools/dotc/core/SymbolLoaders.scala

@@ -134,7 +134,7 @@ object SymbolLoaders {
             report.warning(i"""$what ${tree.name} is in the wrong directory.
                            |It was declared to be in package ${path.reverse.mkString(".")}
                            |But it is found in directory     ${filePath.reverse.mkString(File.separator)}""",
-              tree.sourcePos.focus)
+              tree.srcPos.focus)
           ok
         }
 

compiler/src/dotty/tools/dotc/core/Symbols.scala

@@ -30,7 +30,7 @@ import reporting.Message
 import collection.mutable
 import io.AbstractFile
 import language.implicitConversions
-import util.{SourceFile, NoSource, Property, SourcePosition}
+import util.{SourceFile, NoSource, Property, SourcePosition, SrcPos}
 import scala.collection.JavaConverters._
 import scala.annotation.internal.sharable
 import config.Printers.typr
@@ -47,7 +47,7 @@ object Symbols {
    *  @param id     A unique identifier of the symbol (unique per ContextBase)
    */
   class Symbol private[Symbols] (private var myCoord: Coord, val id: Int)
-    extends Designator with ParamInfo with printing.Showable {
+    extends Designator, ParamInfo, SrcPos, printing.Showable {
 
     type ThisName <: Name
 
@@ -321,6 +321,11 @@ object Symbols {
       (if (src.exists) src else ctx.source).atSpan(span)
     }
 
+    /** This positioned item, widened to `SrcPos`. Used to make clear we only need the
+     *  position, typically for error reporting.
+     */
+    final def srcPos: SrcPos = this
+
     // ParamInfo types and methods
     def isTypeParam(using Context): Boolean = denot.is(TypeParam)
     def paramName(using Context): ThisName = name.asInstanceOf[ThisName]

compiler/src/dotty/tools/dotc/core/TypeOps.scala

@@ -6,7 +6,6 @@ import Contexts._, Types._, Symbols._, Names._, Flags._
 import SymDenotations._
 import util.Spans._
 import util.Stats
-import util.SourcePosition
 import NameKinds.DepParamName
 import Decorators._
 import StdNames._

compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala

@@ -84,7 +84,7 @@ class TreePickler(pickler: TastyPickler) {
       // I believe it's a bug in typer: the type of an implicit argument refers
       // to a closure parameter outside the closure itself. TODO: track this down, so that we
       // can eliminate this case.
-      report.log(i"pickling reference to as yet undefined $sym in ${sym.owner}", sym.sourcePos)
+      report.log(i"pickling reference to as yet undefined $sym in ${sym.owner}", sym.srcPos)
       pickleForwardSymRef(sym)
   }
 
@@ -622,7 +622,7 @@ class TreePickler(pickler: TastyPickler) {
       }
       catch {
         case ex: TypeError =>
-          report.error(ex.toMessage, tree.sourcePos.focus)
+          report.error(ex.toMessage, tree.srcPos.focus)
         case ex: AssertionError =>
           println(i"error when pickling tree $tree")
           throw ex
@@ -734,7 +734,7 @@ class TreePickler(pickler: TastyPickler) {
 
   def pickle(trees: List[Tree])(using Context): Unit = {
     trees.foreach(tree => if (!tree.isEmpty) pickleTree(tree))
-    def missing = forwardSymRefs.keysIterator.map(sym => sym.showLocated + "(line " + sym.sourcePos.line + ")").toList
+    def missing = forwardSymRefs.keysIterator.map(sym => sym.showLocated + "(line " + sym.srcPos.line + ")").toList
     assert(forwardSymRefs.isEmpty, i"unresolved symbols: $missing%, % when pickling ${ctx.source}")
   }