Merge pull request #223 from scala/backport-lts-3.3-20894

Backport "In selector check, prefix of reference must match import qualifier" to 3.3 LTS

Author: tgodzik

compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

@@ -818,7 +818,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
 
       methSymbol  = dd.symbol
       jMethodName = methSymbol.javaSimpleName
-      returnType  = asmMethodType(dd.symbol).returnType
+      returnType  = asmMethodType(methSymbol).returnType
       isMethSymStaticCtor = methSymbol.isStaticConstructor
 
       resetMethodBookkeeping(dd)
@@ -915,7 +915,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
             for (p <- params) { emitLocalVarScope(p.symbol, veryFirstProgramPoint, onePastLastProgramPoint, force = true) }
           }
 
-          if (isMethSymStaticCtor) { appendToStaticCtor(dd) }
+          if (isMethSymStaticCtor) { appendToStaticCtor() }
         } // end of emitNormalMethodBody()
 
         lineNumber(rhs)
@@ -936,7 +936,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
      *
      *  TODO document, explain interplay with `fabricateStaticInitAndroid()`
      */
-    private def appendToStaticCtor(dd: DefDef): Unit = {
+    private def appendToStaticCtor(): Unit = {
 
       def insertBefore(
             location: asm.tree.AbstractInsnNode,

compiler/src/dotty/tools/backend/jvm/ClassfileWriters.scala

@@ -12,10 +12,10 @@ import java.util.zip.{CRC32, Deflater, ZipEntry, ZipOutputStream}
 
 import dotty.tools.dotc.core.Contexts.*
 import dotty.tools.dotc.core.Decorators.em
+import dotty.tools.dotc.util.chaining.*
 import dotty.tools.io.{AbstractFile, PlainFile, VirtualFile}
 import dotty.tools.io.PlainFile.toPlainFile
 import BTypes.InternalName
-import scala.util.chaining._
 import dotty.tools.io.JarArchive
 
 import scala.language.unsafeNulls
@@ -180,7 +180,7 @@ class ClassfileWriters(frontendAccess: PostProcessorFrontendAccess) {
       // important detail here, even on Windows, Zinc expects the separator within the jar
       // to be the system default, (even if in the actual jar file the entry always uses '/').
       // see https://github.com/sbt/zinc/blob/dcddc1f9cfe542d738582c43f4840e17c053ce81/internal/compiler-bridge/src/main/scala/xsbt/JarUtils.scala#L47
-      val pathInJar = 
+      val pathInJar =
         if File.separatorChar == '/' then relativePath
         else relativePath.replace('/', File.separatorChar)
       PlainFile.toPlainFile(Paths.get(s"${file.absolutePath}!$pathInJar"))

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -8,7 +8,6 @@ import cc.CheckCaptures
 import parsing.Parser
 import Phases.Phase
 import transform.*
-import dotty.tools.backend
 import backend.jvm.{CollectSuperCalls, GenBCode}
 import localopt.StringInterpolatorOpt
 
@@ -35,8 +34,7 @@ class Compiler {
   protected def frontendPhases: List[List[Phase]] =
     List(new Parser) ::             // Compiler frontend: scanner, parser
     List(new TyperPhase) ::         // Compiler frontend: namer, typer
-    List(new CheckUnused.PostTyper) :: // Check for unused elements
-    List(new CheckShadowing) :: // Check shadowing elements
+    List(CheckUnused.PostTyper(), CheckShadowing()) :: // Check for unused, shadowed elements
     List(new YCheckPositions) ::    // YCheck positions
     List(new sbt.ExtractDependencies) :: // Sends information on classes' dependencies to sbt via callbacks
     List(new semanticdb.ExtractSemanticDB.ExtractSemanticInfo) :: // Extract info into .semanticdb files
@@ -51,10 +49,10 @@ class Compiler {
     List(new Pickler) ::            // Generate TASTY info
     List(new Inlining) ::           // Inline and execute macros
     List(new PostInlining) ::       // Add mirror support for inlined code
-    List(new CheckUnused.PostInlining) ::  // Check for unused elements
     List(new Staging) ::            // Check staging levels and heal staged types
     List(new Splicing) ::           // Replace level 1 splices with holes
     List(new PickleQuotes) ::       // Turn quoted trees into explicit run-time data structures
+    List(new CheckUnused.PostInlining) ::  // Check for unused elements
     Nil
 
   /** Phases dealing with the transformation from pickled trees to backend trees */

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

@@ -45,6 +45,14 @@ object desugar {
    */
   val UntupledParam: Property.Key[Unit] = Property.StickyKey()
 
+  /** An attachment key to indicate that a ValDef originated from a pattern.
+   */
+  val PatternVar: Property.Key[Unit] = Property.StickyKey()
+
+  /** An attachment key for Trees originating in for-comprehension, such as tupling of assignments.
+   */
+  val ForArtifact: Property.Key[Unit] = Property.StickyKey()
+
   /** What static check should be applied to a Match? */
   enum MatchCheck {
     case None, Exhaustive, IrrefutablePatDef, IrrefutableGenFrom
@@ -1221,7 +1229,7 @@ object desugar {
       val matchExpr =
         if (tupleOptimizable) rhs
         else
-          val caseDef = CaseDef(pat, EmptyTree, makeTuple(ids))
+          val caseDef = CaseDef(pat, EmptyTree, makeTuple(ids).withAttachment(ForArtifact, ()))
           Match(makeSelector(rhs, MatchCheck.IrrefutablePatDef), caseDef :: Nil)
       vars match {
         case Nil if !mods.is(Lazy) =>
@@ -1251,6 +1259,7 @@ object desugar {
                   ValDef(named.name.asTermName, tpt, selector(n))
                     .withMods(mods)
                     .withSpan(named.span)
+                    .withAttachment(PatternVar, ())
                 )
           flatTree(firstDef :: restDefs)
       }
@@ -1542,6 +1551,7 @@ object desugar {
     val vdef = ValDef(named.name.asTermName, tpt, rhs)
       .withMods(mods)
       .withSpan(original.span.withPoint(named.span.start))
+      .withAttachment(PatternVar, ())
     val mayNeedSetter = valDef(vdef)
     mayNeedSetter
   }
@@ -1733,7 +1743,7 @@ object desugar {
               case _ => Modifiers()
             makePatDef(valeq, mods, defpat, rhs)
           }
-          val rhs1 = makeFor(nme.map, nme.flatMap, GenFrom(defpat0, gen.expr, gen.checkMode) :: Nil, Block(pdefs, makeTuple(id0 :: ids)))
+          val rhs1 = makeFor(nme.map, nme.flatMap, GenFrom(defpat0, gen.expr, gen.checkMode) :: Nil, Block(pdefs, makeTuple(id0 :: ids).withAttachment(ForArtifact, ())))
           val allpats = gen.pat :: pats
           val vfrom1 = GenFrom(makeTuple(allpats), rhs1, GenCheckMode.Ignore)
           makeFor(mapName, flatMapName, vfrom1 :: rest1, body)

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

@@ -31,7 +31,7 @@ object Trees {
 
   /** Property key for backquoted identifiers and definitions */
   val Backquoted: Property.StickyKey[Unit] = Property.StickyKey()
-  
+
   val SyntheticUnit: Property.StickyKey[Unit] = Property.StickyKey()
 
   /** Trees take a parameter indicating what the type of their `tpe` field
@@ -765,6 +765,7 @@ object Trees {
     override def isEmpty: Boolean = !hasType
     override def toString: String =
       s"TypeTree${if (hasType) s"[$typeOpt]" else ""}"
+    def isInferred = false
   }
 
   /** Tree that replaces a level 1 splices in pickled (level 0) quotes.
@@ -787,6 +788,7 @@ object Trees {
    */
   class InferredTypeTree[+T <: Untyped](implicit @constructorOnly src: SourceFile) extends TypeTree[T]:
     type ThisTree[+T <: Untyped] <: InferredTypeTree[T]
+    override def isInferred = true
 
   /** ref.type */
   case class SingletonTypeTree[+T <: Untyped] private[ast] (ref: Tree[T])(implicit @constructorOnly src: SourceFile)

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

@@ -7,7 +7,7 @@ import Settings.*
 import core.Contexts.*
 import printing.Highlighting
 
-import scala.util.chaining.given
+import dotty.tools.dotc.util.chaining.*
 import scala.PartialFunction.cond
 
 trait CliCommand:

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

@@ -12,7 +12,7 @@ import dotty.tools.io.{AbstractFile, Directory, JDK9Reflectors, PlainDirectory}
 import dotty.tools.backend.jvm.BackendUtils.classfileVersionMap
 import Setting.ChoiceWithHelp
 
-import scala.util.chaining.*
+import dotty.tools.dotc.util.chaining.*
 
 import java.util.zip.Deflater
 
@@ -179,28 +179,20 @@ private sealed trait WarningSettings:
     choices = List(
       ChoiceWithHelp("nowarn", ""),
       ChoiceWithHelp("all", ""),
-      ChoiceWithHelp(
-        name = "imports",
-        description = "Warn if an import selector is not referenced.\n" +
-        "NOTE : overrided by -Wunused:strict-no-implicit-warn"),
+      ChoiceWithHelp("imports", "Warn if an import selector is not referenced."),
       ChoiceWithHelp("privates", "Warn if a private member is unused"),
       ChoiceWithHelp("locals", "Warn if a local definition is unused"),
       ChoiceWithHelp("explicits", "Warn if an explicit parameter is unused"),
       ChoiceWithHelp("implicits", "Warn if an implicit parameter is unused"),
       ChoiceWithHelp("params", "Enable -Wunused:explicits,implicits"),
+      ChoiceWithHelp("patvars","Warn if a variable bound in a pattern is unused"),
+      //ChoiceWithHelp("inlined", "Apply -Wunused to inlined expansions"), // TODO
       ChoiceWithHelp("linted", "Enable -Wunused:imports,privates,locals,implicits"),
       ChoiceWithHelp(
         name = "strict-no-implicit-warn",
         description = "Same as -Wunused:import, only for imports of explicit named members.\n" +
         "NOTE : This overrides -Wunused:imports and NOT set by -Wunused:all"
       ),
-      // ChoiceWithHelp("patvars","Warn if a variable bound in a pattern is unused"),
-      ChoiceWithHelp(
-        name = "unsafe-warn-patvars",
-        description = "(UNSAFE) Warn if a variable bound in a pattern is unused.\n" +
-        "This warning can generate false positive, as warning cannot be\n" +
-        "suppressed yet."
-      )
     ),
     default = Nil
   )
@@ -212,7 +204,6 @@ private sealed trait WarningSettings:
     // Is any choice set for -Wunused?
     def any(using Context): Boolean = Wall.value || Wunused.value.nonEmpty
 
-    // overrided by strict-no-implicit-warn
     def imports(using Context) =
       (allOr("imports") || allOr("linted")) && !(strictNoImplicitWarn)
     def locals(using Context) =
@@ -226,9 +217,8 @@ private sealed trait WarningSettings:
     def params(using Context) = allOr("params")
     def privates(using Context) =
       allOr("privates") || allOr("linted")
-    def patvars(using Context) =
-      isChoiceSet("unsafe-warn-patvars") // not with "all"
-      // allOr("patvars") // todo : rename once fixed
+    def patvars(using Context) = allOr("patvars")
+    def inlined(using Context) = isChoiceSet("inlined")
     def linted(using Context) =
       allOr("linted")
     def strictNoImplicitWarn(using Context) =

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

@@ -482,6 +482,8 @@ class Definitions {
     @tu lazy val Predef_undefined: Symbol = ScalaPredefModule.requiredMethod(nme.???)
   @tu lazy val ScalaPredefModuleClass: ClassSymbol = ScalaPredefModule.moduleClass.asClass
 
+  @tu lazy val SameTypeClass: ClassSymbol = requiredClass("scala.=:=")
+  @tu lazy val SameType_refl: Symbol = SameTypeClass.companionModule.requiredMethod(nme.refl)
   @tu lazy val SubTypeClass: ClassSymbol = requiredClass("scala.<:<")
   @tu lazy val SubType_refl: Symbol = SubTypeClass.companionModule.requiredMethod(nme.refl)
 
@@ -816,6 +818,7 @@ class Definitions {
   @tu lazy val QuotedExprClass: ClassSymbol = requiredClass("scala.quoted.Expr")
 
   @tu lazy val QuotesClass: ClassSymbol = requiredClass("scala.quoted.Quotes")
+    @tu lazy val Quotes_reflectModule: Symbol = QuotesClass.requiredClass("reflectModule")
     @tu lazy val Quotes_reflect: Symbol = QuotesClass.requiredValue("reflect")
       @tu lazy val Quotes_reflect_asTerm: Symbol = Quotes_reflect.requiredMethod("asTerm")
       @tu lazy val Quotes_reflect_Apply: Symbol = Quotes_reflect.requiredValue("Apply")
@@ -941,6 +944,7 @@ class Definitions {
   def NonEmptyTupleClass(using Context): ClassSymbol = NonEmptyTupleTypeRef.symbol.asClass
     lazy val NonEmptyTuple_tail: Symbol = NonEmptyTupleClass.requiredMethod("tail")
   @tu lazy val PairClass: ClassSymbol = requiredClass("scala.*:")
+    @tu lazy val PairClass_unapply: Symbol = PairClass.companionModule.requiredMethod("unapply")
 
   @tu lazy val TupleXXLClass: ClassSymbol = requiredClass("scala.runtime.TupleXXL")
   def TupleXXLModule(using Context): Symbol = TupleXXLClass.companionModule
@@ -1031,6 +1035,7 @@ class Definitions {
   @tu lazy val UncheckedCapturesAnnot: ClassSymbol = requiredClass("scala.annotation.unchecked.uncheckedCaptures")
   @tu lazy val VolatileAnnot: ClassSymbol = requiredClass("scala.volatile")
   @tu lazy val WithPureFunsAnnot: ClassSymbol = requiredClass("scala.annotation.internal.WithPureFuns")
+  @tu lazy val LanguageFeatureMetaAnnot: ClassSymbol = requiredClass("scala.annotation.meta.languageFeature")
   @tu lazy val BeanGetterMetaAnnot: ClassSymbol = requiredClass("scala.annotation.meta.beanGetter")
   @tu lazy val BeanSetterMetaAnnot: ClassSymbol = requiredClass("scala.annotation.meta.beanSetter")
   @tu lazy val FieldMetaAnnot: ClassSymbol = requiredClass("scala.annotation.meta.field")

compiler/src/dotty/tools/dotc/report.scala

@@ -1,13 +1,11 @@
 package dotty.tools.dotc
 
-import reporting.*
-import Diagnostic.*
-import util.{SourcePosition, NoSourcePosition, SrcPos}
-import core.*
-import Contexts.*, Flags.*, Symbols.*, Decorators.*
-import config.SourceVersion
 import ast.*
-import config.Feature.sourceVersion
+import core.*, Contexts.*, Flags.*, Symbols.*, Decorators.*
+import config.Feature.sourceVersion, config.SourceVersion
+import reporting.*, Diagnostic.*
+import util.{SourcePosition, NoSourcePosition, SrcPos}
+
 import java.lang.System.currentTimeMillis
 
 object report:
@@ -54,6 +52,9 @@ object report:
     else issueWarning(new FeatureWarning(msg, pos.sourcePos))
   end featureWarning
 
+  def warning(msg: Message, pos: SrcPos, origin: String)(using Context): Unit =
+    issueWarning(LintWarning(msg, addInlineds(pos), origin))
+
   def warning(msg: Message, pos: SrcPos)(using Context): Unit =
     issueWarning(new Warning(msg, addInlineds(pos)))
 

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

@@ -8,9 +8,9 @@ import dotty.tools.dotc.config.Settings.Setting
 import dotty.tools.dotc.core.Contexts.*
 import dotty.tools.dotc.interfaces.Diagnostic.{ERROR, INFO, WARNING}
 import dotty.tools.dotc.util.SourcePosition
+import dotty.tools.dotc.util.chaining.*
 
 import java.util.{Collections, Optional, List => JList}
-import scala.util.chaining.*
 import core.Decorators.toMessage
 
 object Diagnostic:
@@ -36,6 +36,18 @@ object Diagnostic:
     pos: SourcePosition
   ) extends Error(msg, pos)
 
+  /** A Warning with an origin. The semantics of `origin` depend on the warning.
+   *  For example, an unused import warning has an origin that specifies the unused selector.
+   *  The origin of a deprecation is the deprecated element.
+   */
+  trait OriginWarning(val origin: String):
+    self: Warning =>
+
+  /** Lints are likely to be filtered. Provide extra axes for filtering by `-Wconf`.
+   */
+  class LintWarning(msg: Message, pos: SourcePosition, origin: String)
+  extends Warning(msg, pos), OriginWarning(origin)
+
   class Warning(
     msg: Message,
     pos: SourcePosition
@@ -73,13 +85,9 @@ object Diagnostic:
     def enablingOption(using Context): Setting[Boolean] = ctx.settings.unchecked
   }
 
-  class DeprecationWarning(
-    msg: Message,
-    pos: SourcePosition,
-    val origin: String
-  ) extends ConditionalWarning(msg, pos) {
+  class DeprecationWarning(msg: Message, pos: SourcePosition, origin: String)
+  extends ConditionalWarning(msg, pos), OriginWarning(origin):
     def enablingOption(using Context): Setting[Boolean] = ctx.settings.deprecation
-  }
 
   class MigrationWarning(
     msg: Message,
@@ -104,5 +112,5 @@ class Diagnostic(
   override def diagnosticRelatedInformation: JList[interfaces.DiagnosticRelatedInformation] =
     Collections.emptyList()
 
-  override def toString: String = s"$getClass at $pos: $message"
+  override def toString: String = s"$getClass at $pos L${pos.line+1}: $message"
 end Diagnostic