Don't force type vars while typing (named) tuples

dwijnand · Feb 5, 2024 · 2230e58 · 2230e58
1 parent 5583593
commit 2230e58
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Showing 2 changed files with 13 additions and 2 deletions.
diff --git a/compiler/src/dotty/tools/dotc/ast/Desugar.scala b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
@@ -1505,8 +1505,10 @@ object desugar {
     var names = elems.collect:
       case NamedArg(name, arg) => name
     if names.isEmpty then
-      typer.Inferencing.isFullyDefined(pt, typer.ForceDegree.failBottom)
-      names = pt.namedTupleNames
+      val pt1 = pt.stripTypeVar match
+        case p: TypeParamRef => ctx.typerState.constraint.entry(p).hiBound
+        case _               => NoType
+      names = pt1.orElse(pt).namedTupleNames
     if names.isEmpty || ctx.mode.is(Mode.Pattern) then
       tup
     else

diff --git a/tests/run/named-patterns.scala b/tests/run/named-patterns.scala
@@ -72,3 +72,12 @@ object Test1:
     p3 match
       case (Person2(nn, a), Address(c, z, s, number)) =>
         println(s"$nn, aged $a in $z $c, $s $number")
+
+  // don't force type vars too early (while typing named tuples)
+  def ifBefore[T](end: Int)(op: => T, default: T): T = ???
+  def ifBeforeTest(end: Int) =
+    sealed trait Type
+    case class TypeRef() extends Type
+    case object NoType extends Type
+    def readQualId(): (Int, TypeRef) = ???
+    val (mixId, mixTpe) = ifBefore(end)(readQualId(), (2, NoType))