From cc0c4445af2ac8a667151ed98890fdb33b200cd8 Mon Sep 17 00:00:00 2001
From: rochala <rochala@tutanota.com>
Date: Fri, 20 Dec 2024 15:06:04 +0100
Subject: [PATCH] Fix named tuple crash + actually filter used names in named
 tuples

---
 .../main/dotty/tools/pc/InferExpectedType.scala    |  3 ++-
 .../pc/completions/NamedPatternCompletions.scala   | 14 +++++++++++---
 .../completion/CompletionNamedPatternSuite.scala   |  6 ++----
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/presentation-compiler/src/main/dotty/tools/pc/InferExpectedType.scala b/presentation-compiler/src/main/dotty/tools/pc/InferExpectedType.scala
index d2a004075196..41bd2b61e080 100644
--- a/presentation-compiler/src/main/dotty/tools/pc/InferExpectedType.scala
+++ b/presentation-compiler/src/main/dotty/tools/pc/InferExpectedType.scala
@@ -93,7 +93,8 @@ object InterCompletionType:
       case UnApply(fun, _, pats) :: _ =>
         val ind = pats.indexWhere(_.span.contains(span))
         if ind < 0 then None
-        else Some(UnapplyArgs(fun.tpe.finalResultType, fun, pats, NoSourcePosition).argTypes(ind))
+        else
+          UnapplyArgs(fun.tpe.finalResultType, fun, pats, NoSourcePosition).argTypes.get(ind)
       // f(@@)
       case (app: Apply) :: rest =>
         val param =
diff --git a/presentation-compiler/src/main/dotty/tools/pc/completions/NamedPatternCompletions.scala b/presentation-compiler/src/main/dotty/tools/pc/completions/NamedPatternCompletions.scala
index bfa01cd128e1..27f48faaf7b9 100644
--- a/presentation-compiler/src/main/dotty/tools/pc/completions/NamedPatternCompletions.scala
+++ b/presentation-compiler/src/main/dotty/tools/pc/completions/NamedPatternCompletions.scala
@@ -1,6 +1,7 @@
 package dotty.tools.pc.completions
 
 import dotty.tools.dotc.ast.tpd.*
+import dotty.tools.dotc.ast.untpd
 import dotty.tools.dotc.core.Flags
 import dotty.tools.dotc.core.Names.Name
 import dotty.tools.dotc.core.StdNames.*
@@ -10,6 +11,8 @@ import dotty.tools.dotc.core.Symbols.defn
 import dotty.tools.dotc.core.Contexts.*
 import dotty.tools.dotc.core.Types.*
 import dotty.tools.dotc.util.SourcePosition
+import dotty.tools.dotc.ast.NavigateAST
+
 import scala.meta.internal.pc.CompletionFuzzy
 
 object NamedPatternCompletions:
@@ -38,8 +41,13 @@ object NamedPatternCompletions:
           rest.collectFirst: // We can't complete names without knowing the type of selector
             case Match(selector, _) => selector
           .flatMap: selector =>
+            // Named patterns are desugared to normal binds without original arg name info
+            val patterns = NavigateAST.untypedPath(unapply).collectFirst:
+              case untpd.Tuple(elems) => elems
+            .getOrElse(Nil)
+
             if selector.tpe.widenDealias.isNamedTupleType then
-              Some(selector.tpe.widenDealias.namedTupleElementTypes.toMap, unapply.patterns)
+              Some(selector.tpe.widenDealias.namedTupleElementTypes.toMap, patterns)
             else None
 
       // case User(nam@@
@@ -89,10 +97,10 @@ object NamedPatternCompletions:
   def contribute(
     completionPos: CompletionPos,
     namesToArgs: Map[Name, Type],
-    patterns: List[Tree]
+    patterns: List[untpd.Tree]
   )(using Context): List[CompletionValue] =
     val usedNames = patterns.collect:
-      case NamedArg(name, _) => name.asTermName
+      case untpd.NamedArg(name, _) => name.asTermName
 
     val remainingParams = namesToArgs -- usedNames
     remainingParams
diff --git a/presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionNamedPatternSuite.scala b/presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionNamedPatternSuite.scala
index 4c77a1d85edf..5a0409fc8725 100644
--- a/presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionNamedPatternSuite.scala
+++ b/presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionNamedPatternSuite.scala
@@ -50,8 +50,7 @@ class CompletionNamedPatternSuite extends BaseCompletionSuite:
          |def idsWithName(name: String) = user match
          |  case (name = supername, na@@
          |""".stripMargin,
-      """name = : String
-        |surname = : String""".stripMargin
+      """surname = : String""".stripMargin
     )
 
   @Test def `named-tuples-3` =
@@ -65,8 +64,7 @@ class CompletionNamedPatternSuite extends BaseCompletionSuite:
          |def idsWithName(name: String) = user match
          |  case (na@@, name = name) =>
          |""".stripMargin,
-      """name = : String
-        |surname = : String""".stripMargin
+      """surname = : String""".stripMargin
     )
 
   @Test def `named-tuples-synthetic` =