Backport "Backport pc changes from metals" to LTS (#20883)

Backports #19617 to the LTS branch.

PR submitted by the release tooling.
[skip ci]

presentation-compiler/src/main/dotty/tools/pc/completions/CompletionProvider.scala

@@ -243,21 +243,29 @@ class CompletionProvider(
               r match
                 case IndexedContext.Result.InScope =>
                   mkItem(
-                    ident.backticked(backtickSoftKeyword) + completionTextSuffix
+                    v.insertText.getOrElse(
+                      ident.backticked(
+                        backtickSoftKeyword
+                      ) + completionTextSuffix
+                    ),
+                    range = v.range,
                   )
                 case _ if isInStringInterpolation =>
                   mkItem(
-                    "{" + sym.fullNameBackticked + completionTextSuffix + "}"
+                    "{" + sym.fullNameBackticked + completionTextSuffix + "}",
+                    range = v.range
                   )
                 case _ if v.isExtensionMethod =>
                   mkItem(
-                    ident.backticked(backtickSoftKeyword) + completionTextSuffix
+                    ident.backticked(backtickSoftKeyword) + completionTextSuffix,
+                    range = v.range
                   )
                 case _ =>
                   mkItem(
                     sym.fullNameBackticked(
                       backtickSoftKeyword
-                    ) + completionTextSuffix
+                    ) + completionTextSuffix,
+                    range = v.range
                   )
               end match
           end match

presentation-compiler/src/main/dotty/tools/pc/completions/CompletionValue.scala

@@ -6,6 +6,7 @@ import scala.meta.internal.pc.CompletionItemData
 import dotty.tools.dotc.core.Contexts.Context
 import dotty.tools.dotc.core.Denotations.Denotation
 import dotty.tools.dotc.core.Flags.*
+import dotty.tools.dotc.core.StdNames.nme
 import dotty.tools.dotc.core.Symbols.Symbol
 import dotty.tools.dotc.core.Types.Type
 import dotty.tools.pc.printer.ShortenedTypePrinter
@@ -108,7 +109,7 @@ object CompletionValue:
         s"${label}${description(printer)}"
       else s"$label: ${description(printer)}"
 
-    private def labelWithSuffix(printer: ShortenedTypePrinter)(using Context): String =
+    protected def labelWithSuffix(printer: ShortenedTypePrinter)(using Context): String =
       if snippetSuffix.addLabelSnippet
       then
         val printedParams = symbol.info.typeParams.map(p =>
@@ -145,6 +146,11 @@ object CompletionValue:
     override def isFromWorkspace: Boolean = true
     override def completionItemDataKind: Integer = CompletionSource.WorkspaceKind.ordinal
 
+    override def labelWithDescription(printer: ShortenedTypePrinter)(using Context): String =
+      if symbol.is(Method) && symbol.name != nme.apply then
+        s"${labelWithSuffix(printer)} - ${printer.fullNameString(symbol.effectiveOwner)}"
+      else super.labelWithDescription(printer)
+
   /**
    * CompletionValue for old implicit classes methods via SymbolSearch
    */
@@ -268,6 +274,7 @@ object CompletionValue:
     )(using Context): String =
       if isExtension then s"${printer.completionSymbol(symbol)} (extension)"
       else super.description(printer)
+    override def isExtensionMethod: Boolean = isExtension
   end Interpolator
 
   case class MatchCompletion(

presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionInterpolatorSuite.scala

@@ -635,7 +635,7 @@ class CompletionInterpolatorSuite extends BaseCompletionSuite:
          |""".stripMargin,
       """|class Paths
          |object Main {
-         |  s"this is an interesting {java.nio.file.Paths}"
+         |  s"this is an interesting ${java.nio.file.Paths}"
          |}
          |""".stripMargin,
       assertSingleItem = false,
@@ -710,6 +710,26 @@ class CompletionInterpolatorSuite extends BaseCompletionSuite:
       filterText = "aaa.plus"
     )
 
+
+  @Test def `extension3` =
+    checkEdit(
+      """|trait Cursor
+         |
+         |extension (c: Cursor) def spelling: String = "hello"
+         |object Main {
+         |  val c = new Cursor {}
+         |  val x = s"$c.spelli@@"
+         |}
+         |""".stripMargin,
+      """|trait Cursor
+         |
+         |extension (c: Cursor) def spelling: String = "hello"
+         |object Main {
+         |  val c = new Cursor {}
+         |  val x = s"${c.spelling$0}"
+         |}""".stripMargin
+    )
+
   @Test def `filter-by-type` =
     check(
       """|package example

presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionWorkspaceSuite.scala

@@ -768,8 +768,29 @@ class CompletionWorkspaceSuite extends BaseCompletionSuite:
          |  def main: Unit = incre@@
          |""".stripMargin,
       """|increment3: Int
-         |increment: Int
-         |increment2: Int
+         |increment - a: Int
+         |increment2 - a.c: Int
+         |""".stripMargin
+    )
+
+  @Test def `indent-method` =
+    check(
+      """|package a:
+         |  val y = 123
+         |  given intGiven: Int = 123
+         |  type Alpha = String
+         |  class Foo(x: Int)
+         |  object X:
+         |    val x = 123
+         |  def fooBar(x: Int) = x + 1
+         |  package b:
+         |    def fooBar(x: String) = x.length
+         |
+         |package c:
+         |  def main() = foo@@
+         |""".stripMargin,
+      """|fooBar - a(x: Int): Int
+         |fooBar - a.b(x: String): Int
          |""".stripMargin
     )
 
@@ -848,5 +869,21 @@ class CompletionWorkspaceSuite extends BaseCompletionSuite:
          |  }
          |}
          |""".stripMargin,
-      filter = _.contains("mmmm(x: Int)")
+      filter = _.contains("mmmm - demo.O")
+    )
+
+  @Test def `method-label` =
+    check(
+      """|package demo
+         |
+         |object O {
+         | def method(i: Int): Int = i + 1
+         |}
+         |
+         |object Main {
+         |  val x = meth@@
+         |}
+         |""".stripMargin,
+      """|method - demo.O(i: Int): Int
+         |""".stripMargin
     )