Add missing span to extension method select (#18557)

For:
```Demo.scala
class MyIntOut(val value: Int)
object MyIntOut:
  extension (i: MyIntOut) def uneven = i.value % 2 == 1

val a = MyIntOut(1).uneven
```
`uneven` call in the typed tree has span `<126..126>`, where it should
be `<138..144>`.

connected to: scalameta/metals#5630

I'm open to suggestions on how to do it nicer.

Author: bishabosha

Diff for: compiler/src/dotty/tools/dotc/inlines/Inliner.scala

@@ -771,7 +771,7 @@ class Inliner(val call: tpd.Tree)(using Context):
 
     override def typedSelect(tree: untpd.Select, pt: Type)(using Context): Tree = {
       val locked = ctx.typerState.ownedVars
-      val qual1 = typed(tree.qualifier, shallowSelectionProto(tree.name, pt, this))
+      val qual1 = typed(tree.qualifier, shallowSelectionProto(tree.name, pt, this, tree.nameSpan))
       val resNoReduce = untpd.cpy.Select(tree)(qual1, tree.name).withType(tree.typeOpt)
       val reducedProjection = reducer.reduceProjection(resNoReduce)
       if reducedProjection.isType then

Diff for: compiler/src/dotty/tools/dotc/typer/Applications.scala

@@ -976,7 +976,7 @@ trait Applications extends Compatibility {
             val resultType =
               if !originalResultType.isRef(defn.ObjectClass) then originalResultType
               else AvoidWildcardsMap()(proto.resultType.deepenProtoTrans) match
-                case SelectionProto(nme.asInstanceOf_, PolyProto(_, resTp), _, _) => resTp
+                case SelectionProto(nme.asInstanceOf_, PolyProto(_, resTp), _, _, _) => resTp
                 case resTp if isFullyDefined(resTp, ForceDegree.all) => resTp
                 case _ => defn.ObjectType
             val methType = MethodType(proto.typedArgs().map(_.tpe.widen), resultType)

Diff for: compiler/src/dotty/tools/dotc/typer/ErrorReporting.scala

@@ -8,6 +8,7 @@ import Types._, ProtoTypes._, Contexts._, Decorators._, Denotations._, Symbols._
 import Implicits._, Flags._, Constants.Constant
 import Trees._
 import NameOps._
+import util.Spans.NoSpan
 import util.SrcPos
 import config.Feature
 import reporting._
@@ -275,7 +276,7 @@ object ErrorReporting {
       else
         val add = suggestImports(
           ViewProto(qualType.widen,
-            SelectionProto(tree.name, WildcardType, NoViewsAllowed, privateOK = false)))
+            SelectionProto(tree.name, WildcardType, NoViewsAllowed, privateOK = false, NoSpan)))
         if add.isEmpty then ""
         else ", but could be made available as an extension method." ++ add
     end selectErrorAddendum

Diff for: compiler/src/dotty/tools/dotc/typer/Implicits.scala

@@ -76,7 +76,7 @@ object Implicits:
    *  method with the selecting name? False otherwise.
    */
   def hasExtMethod(tp: Type, expected: Type)(using Context) = expected match
-    case selProto @ SelectionProto(selName: TermName, _, _, _) =>
+    case selProto @ SelectionProto(selName: TermName, _, _, _, _) =>
       tp.memberBasedOnFlags(selName, required = ExtensionMethod).exists
     case _ =>
       false
@@ -454,7 +454,7 @@ object Implicits:
     def clarify(tp: Type)(using Context): Type = tp
 
     final protected def qualify(using Context): String = expectedType match {
-      case SelectionProto(name, mproto, _, _) if !argument.isEmpty =>
+      case SelectionProto(name, mproto, _, _, _) if !argument.isEmpty =>
         i"provide an extension method `$name` on ${argument.tpe}"
       case NoType =>
         if (argument.isEmpty) i"match expected type"
@@ -866,8 +866,8 @@ trait Implicits:
       NoMatchingImplicitsFailure
     else {
       def adjust(to: Type) = to.stripTypeVar.widenExpr match {
-        case SelectionProto(name, memberProto, compat, true) =>
-          SelectionProto(name, memberProto, compat, privateOK = false)
+        case SelectionProto(name, memberProto, compat, true, nameSpan) =>
+          SelectionProto(name, memberProto, compat, privateOK = false, nameSpan)
         case tp => tp
       }
 
@@ -1161,10 +1161,10 @@ trait Implicits:
               pt, locked)
           }
           pt match
-            case selProto @ SelectionProto(selName: TermName, mbrType, _, _) =>
+            case selProto @ SelectionProto(selName: TermName, mbrType, _, _, nameSpan) =>
 
               def tryExtension(using Context) =
-                extMethodApply(untpd.Select(untpdGenerated, selName), argument, mbrType)
+                extMethodApply(untpd.Select(untpdGenerated, selName).withSpan(nameSpan), argument, mbrType)
 
               def tryConversionForSelection(using Context) =
                 val converted = tryConversion

Diff for: compiler/src/dotty/tools/dotc/typer/ImportSuggestions.scala

@@ -237,7 +237,7 @@ trait ImportSuggestions:
           // don't suggest things that are imported by default
 
       def extensionImports = pt match
-        case ViewProto(argType, SelectionProto(name: TermName, _, _, _)) =>
+        case ViewProto(argType, SelectionProto(name: TermName, _, _, _, _)) =>
           roots.flatMap(extensionMethod(_, name, argType))
         case _ =>
           Nil

Diff for: compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala

@@ -21,6 +21,7 @@ import dotty.tools.dotc.core.Flags.Transparent
 import dotty.tools.dotc.config.{ Feature, SourceVersion }
 
 import scala.annotation.internal.sharable
+import dotty.tools.dotc.util.Spans.{NoSpan, Span}
 
 object ProtoTypes {
 
@@ -180,7 +181,7 @@ object ProtoTypes {
    *
    *       [ ].name: proto
    */
-  abstract case class SelectionProto(name: Name, memberProto: Type, compat: Compatibility, privateOK: Boolean)
+  abstract case class SelectionProto(name: Name, memberProto: Type, compat: Compatibility, privateOK: Boolean, nameSpan: Span)
   extends CachedProxyType with ProtoType with ValueTypeOrProto {
 
     /** Is the set of members of this type unknown, in the sense that we
@@ -243,24 +244,24 @@ object ProtoTypes {
 
     def underlying(using Context): Type = WildcardType
 
-    def derivedSelectionProto(name: Name, memberProto: Type, compat: Compatibility)(using Context): SelectionProto =
-      if ((name eq this.name) && (memberProto eq this.memberProto) && (compat eq this.compat)) this
-      else SelectionProto(name, memberProto, compat, privateOK)
+    def derivedSelectionProto(name: Name, memberProto: Type, compat: Compatibility, nameSpan: Span)(using Context): SelectionProto =
+      if ((name eq this.name) && (memberProto eq this.memberProto) && (compat eq this.compat) && (nameSpan == this.nameSpan)) this
+      else SelectionProto(name, memberProto, compat, privateOK, nameSpan)
 
     override def isErroneous(using Context): Boolean =
       memberProto.isErroneous
 
     override def unusableForInference(using Context): Boolean =
       memberProto.unusableForInference
 
-    def map(tm: TypeMap)(using Context): SelectionProto = derivedSelectionProto(name, tm(memberProto), compat)
+    def map(tm: TypeMap)(using Context): SelectionProto = derivedSelectionProto(name, tm(memberProto), compat, nameSpan)
     def fold[T](x: T, ta: TypeAccumulator[T])(using Context): T = ta(x, memberProto)
 
     override def deepenProto(using Context): SelectionProto =
-      derivedSelectionProto(name, memberProto.deepenProto, compat)
+      derivedSelectionProto(name, memberProto.deepenProto, compat, nameSpan)
 
     override def deepenProtoTrans(using Context): SelectionProto =
-      derivedSelectionProto(name, memberProto.deepenProtoTrans, compat)
+      derivedSelectionProto(name, memberProto.deepenProtoTrans, compat, nameSpan)
 
     override def computeHash(bs: Hashable.Binders): Int = {
       val delta = (if (compat eq NoViewsAllowed) 1 else 0) | (if (privateOK) 2 else 0)
@@ -281,24 +282,24 @@ object ProtoTypes {
     }
   }
 
-  class CachedSelectionProto(name: Name, memberProto: Type, compat: Compatibility, privateOK: Boolean)
-  extends SelectionProto(name, memberProto, compat, privateOK)
+  class CachedSelectionProto(name: Name, memberProto: Type, compat: Compatibility, privateOK: Boolean, nameSpan: Span)
+  extends SelectionProto(name, memberProto, compat, privateOK, nameSpan)
 
   object SelectionProto {
-    def apply(name: Name, memberProto: Type, compat: Compatibility, privateOK: Boolean)(using Context): SelectionProto = {
-      val selproto = new CachedSelectionProto(name, memberProto, compat, privateOK)
+    def apply(name: Name, memberProto: Type, compat: Compatibility, privateOK: Boolean, nameSpan: Span)(using Context): SelectionProto = {
+      val selproto = new CachedSelectionProto(name, memberProto, compat, privateOK, nameSpan)
       if (compat eq NoViewsAllowed) unique(selproto) else selproto
     }
   }
 
   /** Create a selection proto-type, but only one level deep;
    *  treat constructors specially
    */
-  def shallowSelectionProto(name: Name, tp: Type, typer: Typer)(using Context): TermType =
+  def shallowSelectionProto(name: Name, tp: Type, typer: Typer, nameSpan: Span)(using Context): TermType =
     if (name.isConstructorName) WildcardType
     else tp match
-      case tp: UnapplyFunProto => new UnapplySelectionProto(name)
-      case tp => SelectionProto(name, IgnoredProto(tp), typer, privateOK = true)
+      case tp: UnapplyFunProto => new UnapplySelectionProto(name, nameSpan)
+      case tp => SelectionProto(name, IgnoredProto(tp), typer, privateOK = true, nameSpan)
 
   /** A prototype for expressions [] that are in some unspecified selection operation
    *
@@ -308,12 +309,12 @@ object ProtoTypes {
    *  operation is further selection. In this case, the expression need not be a value.
    *  @see checkValue
    */
-  @sharable object AnySelectionProto extends SelectionProto(nme.WILDCARD, WildcardType, NoViewsAllowed, true)
+  @sharable object AnySelectionProto extends SelectionProto(nme.WILDCARD, WildcardType, NoViewsAllowed, true, NoSpan)
 
-  @sharable object SingletonTypeProto extends SelectionProto(nme.WILDCARD, WildcardType, NoViewsAllowed, true)
+  @sharable object SingletonTypeProto extends SelectionProto(nme.WILDCARD, WildcardType, NoViewsAllowed, true, NoSpan)
 
   /** A prototype for selections in pattern constructors */
-  class UnapplySelectionProto(name: Name) extends SelectionProto(name, WildcardType, NoViewsAllowed, true)
+  class UnapplySelectionProto(name: Name, nameSpan: Span) extends SelectionProto(name, WildcardType, NoViewsAllowed, true, nameSpan)
 
   trait ApplyingProto extends ProtoType   // common trait of ViewProto and FunProto
   trait FunOrPolyProto extends ProtoType: // common trait of PolyProto and FunProto
@@ -612,7 +613,7 @@ object ProtoTypes {
     def isMatchedBy(tp: Type, keepConstraint: Boolean)(using Context): Boolean =
       ctx.typer.isApplicableType(tp, argType :: Nil, resultType) || {
         resType match {
-          case selProto @ SelectionProto(selName: TermName, mbrType, _, _) =>
+          case selProto @ SelectionProto(selName: TermName, mbrType, _, _, _) =>
             ctx.typer.hasExtensionMethodNamed(tp, selName, argType, mbrType)
               //.reporting(i"has ext $tp $name $argType $mbrType: $result")
           case _ =>
@@ -934,7 +935,7 @@ object ProtoTypes {
       }
       approxOr
     case tp: SelectionProto =>
-      tp.derivedSelectionProto(tp.name, wildApprox(tp.memberProto, theMap, seen, internal), NoViewsAllowed)
+      tp.derivedSelectionProto(tp.name, wildApprox(tp.memberProto, theMap, seen, internal), NoViewsAllowed, tp.nameSpan)
     case tp: ViewProto =>
       tp.derivedViewProto(
           wildApprox(tp.argType, theMap, seen, internal),

Diff for: compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -760,7 +760,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
     record("typedSelect")
 
     def typeSelectOnTerm(using Context): Tree =
-      val qual = typedExpr(tree.qualifier, shallowSelectionProto(tree.name, pt, this))
+      val qual = typedExpr(tree.qualifier, shallowSelectionProto(tree.name, pt, this, tree.nameSpan))
       typedSelect(tree, pt, qual).withSpan(tree.span).computeNullable()
 
     def javaSelectOnType(qual: Tree)(using Context) =
@@ -790,7 +790,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
       tryAlternatively(typeSelectOnTerm)(fallBack)
 
     if (tree.qualifier.isType) {
-      val qual1 = typedType(tree.qualifier, shallowSelectionProto(tree.name, pt, this))
+      val qual1 = typedType(tree.qualifier, shallowSelectionProto(tree.name, pt, this, tree.nameSpan))
       assignType(cpy.Select(tree)(qual1, tree.name), qual1)
     }
     else if (ctx.isJava && tree.name.isTypeName)
@@ -3513,7 +3513,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
         then
           Some(adapt(tree, pt, locked))
         else
-          val selProto = SelectionProto(name, pt, NoViewsAllowed, privateOK = false)
+          val selProto = SelectionProto(name, pt, NoViewsAllowed, privateOK = false, tree.nameSpan)
           if selProto.isMatchedBy(qual.tpe) || tree.hasAttachment(InsertedImplicitOnQualifier) then
             None
           else
@@ -3538,7 +3538,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
       (tree: untpd.Select, pt: Type, mbrProto: Type, qual: Tree, locked: TypeVars, compat: Compatibility, inSelect: Boolean)
       (using Context): Tree =
 
-    def selectionProto = SelectionProto(tree.name, mbrProto, compat, privateOK = inSelect)
+    def selectionProto = SelectionProto(tree.name, mbrProto, compat, privateOK = inSelect, tree.nameSpan)
 
     def tryExtension(using Context): Tree =
       val altImports = new mutable.ListBuffer[TermRef]()
@@ -3968,7 +3968,7 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
        *  function prototype `(...)R`. Otherwise `pt`.
        */
       def ptWithoutRedundantApply: Type = pt.revealIgnored match
-        case SelectionProto(nme.apply, mpt, _, _) =>
+        case SelectionProto(nme.apply, mpt, _, _, _) =>
           mpt.revealIgnored match
             case fpt: FunProto => fpt
             case _ => pt

Diff for: presentation-compiler/test/dotty/tools/pc/tests/definition/PcDefinitionSuite.scala

@@ -401,3 +401,13 @@ class PcDefinitionSuite extends BasePcDefinitionSuite:
          |
          |""".stripMargin
     )
+
+  @Test def `implicit-extension` =
+    check(
+      """|class MyIntOut(val value: Int)
+         |object MyIntOut:
+         |  extension (i: MyIntOut) def <<uneven>> = i.value % 2 == 1
+         |
+         |val a = MyIntOut(1).un@@even
+         |""".stripMargin,
+    )

Diff for: presentation-compiler/test/dotty/tools/pc/tests/highlight/DocumentHighlightSuite.scala

@@ -1143,3 +1143,34 @@ class DocumentHighlightSuite extends BaseDocumentHighlightSuite:
          |  case MySome[<<AA>>](value: <<A@@A>>) extends MyOption[Int]
          |""".stripMargin,
     )
+
+  @Test def `implicit-extension` =
+    check(
+      """|class MyIntOut(val value: Int)
+         |object MyIntOut:
+         |  extension (i: MyIntOut) def <<uneven>> = i.value % 2 == 1
+         |
+         |val a = MyIntOut(1)
+         |val m = a.<<un@@even>>
+         |""".stripMargin,
+    )
+
+  @Test def `implicit-extension-2` =
+    check(
+      """|class MyIntOut(val value: Int)
+         |object MyIntOut:
+         |  extension (i: MyIntOut) def <<uneven>>(u: Int) = i.value % 2 == 1
+         |
+         |val a = MyIntOut(1).<<un@@even>>(3)
+         |""".stripMargin,
+    )
+
+  @Test def `implicit-extension-infix` =
+    check(
+      """|class MyIntOut(val value: Int)
+         |object MyIntOut:
+         |  extension (i: MyIntOut) def <<++>>(u: Int) = i.value + u
+         |
+         |val a = MyIntOut(1) <<+@@+>> 3
+         |""".stripMargin,
+    )

Diff for: presentation-compiler/test/dotty/tools/pc/tests/hover/HoverTypeSuite.scala

@@ -355,3 +355,15 @@ class HoverTypeSuite extends BaseHoverSuite:
       """|val ddd: Int
          |""".stripMargin.hover,
     )
+
+  @Test def `infix-extension` =
+    check(
+      """|class MyIntOut(val value: Int)
+         |object MyIntOut:
+         |  extension (i: MyIntOut) def uneven = i.value % 2 == 1
+         |
+         |val a = MyIntOut(1).un@@even
+         |""".stripMargin,
+      """|extension (i: MyIntOut) def uneven: Boolean
+         |""".stripMargin.hover,
+    )

Diff for: tests/semanticdb/expect/Extension.expect.scala

@@ -16,3 +16,12 @@ extension (s/*<-ext::Extension$package.readInto().(s)*/: String/*->scala::Predef
 
 trait Functor/*<-ext::Functor#*/[F/*<-ext::Functor#[F]*/[_]]:
   extension [T/*<-ext::Functor#map().[T]*/](t/*<-ext::Functor#map().(t)*/: F/*->ext::Functor#[F]*/[T/*->ext::Functor#map().[T]*/]) def map/*<-ext::Functor#map().*/[U/*<-ext::Functor#map().[U]*/](f/*<-ext::Functor#map().(f)*/: T/*->ext::Functor#map().[T]*/ => U/*->ext::Functor#map().[U]*/): F/*->ext::Functor#[F]*/[U/*->ext::Functor#map().[U]*/]
+
+opaque type Deck/*<-ext::Extension$package.Deck#*/ = Long/*->scala::Long#*/
+object Deck/*<-ext::Extension$package.Deck.*/:
+  extension (data/*<-ext::Extension$package.Deck.fooSize().(data)*/: Deck/*->ext::Extension$package.Deck#*/)
+    def fooSize/*<-ext::Extension$package.Deck.fooSize().*/: Int/*->scala::Int#*/ = ???/*->scala::Predef.`???`().*/
+
+object DeckUsage/*<-ext::DeckUsage.*/:
+  val deck/*<-ext::DeckUsage.deck.*/: Deck/*->ext::Extension$package.Deck#*/ = ???/*->scala::Predef.`???`().*/
+  deck/*->ext::DeckUsage.deck.*/.fooSize/*->ext::Extension$package.Deck.fooSize().*/

Diff for: tests/semanticdb/expect/Extension.scala

@@ -16,3 +16,12 @@ extension (s: String)
 
 trait Functor[F[_]]:
   extension [T](t: F[T]) def map[U](f: T => U): F[U]
+
+opaque type Deck = Long
+object Deck:
+  extension (data: Deck)
+    def fooSize: Int = ???
+
+object DeckUsage:
+  val deck: Deck = ???
+  deck.fooSize

Diff for: tests/semanticdb/metac.expect

@@ -1450,12 +1450,18 @@ Schema => SemanticDB v4
 Uri => Extension.scala
 Text => empty
 Language => Scala
-Symbols => 26 entries
-Occurrences => 52 entries
+Symbols => 32 entries
+Occurrences => 66 entries
 Synthetics => 1 entries
 
 Symbols:
-ext/Extension$package. => final package object ext extends Object { self: ext.type => +6 decls }
+ext/DeckUsage. => final object DeckUsage extends Object { self: DeckUsage.type => +2 decls }
+ext/DeckUsage.deck. => val method deck Deck
+ext/Extension$package. => final package object ext extends Object { self: ext.type { opaque type Deck  } => +9 decls }
+ext/Extension$package.Deck# => opaque type Deck 
+ext/Extension$package.Deck. => final object Deck extends Object { self: Deck.type => +2 decls }
+ext/Extension$package.Deck.fooSize(). => method fooSize (param data: Deck): Int
+ext/Extension$package.Deck.fooSize().(data) => param data: Deck
 ext/Extension$package.`#*#`(). => method #*# (param s: String)(param i: Int): Tuple2[String, Int]
 ext/Extension$package.`#*#`().(i) => param i: Int
 ext/Extension$package.`#*#`().(s) => param s: String
@@ -1535,6 +1541,20 @@ Occurrences:
 [17:44..17:45): U -> ext/Functor#map().[U]
 [17:48..17:49): F -> ext/Functor#[F]
 [17:50..17:51): U -> ext/Functor#map().[U]
+[19:12..19:16): Deck <- ext/Extension$package.Deck#
+[19:19..19:23): Long -> scala/Long#
+[20:7..20:11): Deck <- ext/Extension$package.Deck.
+[21:13..21:17): data <- ext/Extension$package.Deck.fooSize().(data)
+[21:19..21:23): Deck -> ext/Extension$package.Deck#
+[22:8..22:15): fooSize <- ext/Extension$package.Deck.fooSize().
+[22:17..22:20): Int -> scala/Int#
+[22:23..22:26): ??? -> scala/Predef.`???`().
+[24:7..24:16): DeckUsage <- ext/DeckUsage.
+[25:6..25:10): deck <- ext/DeckUsage.deck.
+[25:12..25:16): Deck -> ext/Extension$package.Deck#
+[25:19..25:22): ??? -> scala/Predef.`???`().
+[26:2..26:6): deck -> ext/DeckUsage.deck.
+[26:7..26:14): fooSize -> ext/Extension$package.Deck.fooSize().
 
 Synthetics:
 [14:46..14:61):summon[Read[T]] => *(x$2)