No indent in named arg pattern

Author: som-snytt

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -671,11 +671,14 @@ object Parsers {
         ts.toList
       else leading :: Nil
 
-    def maybeNamed(op: () => Tree): () => Tree = () =>
+    def maybeNamed(location: Location, op: () => Tree): () => Tree = () =>
       if isIdent && in.lookahead.token == EQUALS && sourceVersion.enablesNamedTuples then
         atSpan(in.offset):
           val name = ident()
           in.nextToken()
+          if location.inPattern && in.token == INDENT then
+            in.currentRegion = in.currentRegion.outer
+            in.nextToken()
           NamedArg(name, op())
       else op()
 
@@ -2958,7 +2961,7 @@ object Parsers {
           if isErased then isFormalParams = true
           if isFormalParams then binding(Modifiers())
           else
-            val t = maybeNamed(exprInParens)()
+            val t = maybeNamed(Location.InParens, exprInParens)()
             if t.isInstanceOf[ValDef] then isFormalParams = true
             t
         commaSeparatedRest(exprOrBinding(), exprOrBinding)
@@ -3411,8 +3414,8 @@ object Parsers {
      *                      |  NamedPattern {‘,’ NamedPattern}
      *  NamedPattern      ::=  id '=' Pattern
      */
-    def patterns(location: Location = Location.InPattern): List[Tree] =
-      commaSeparated(maybeNamed(() => pattern(location)))
+    def patterns(location: Location = Location.InPattern): List[Tree] = // default used from Markup
+      commaSeparated(maybeNamed(location, () => pattern(location)))
         // check that patterns are all named or all unnamed is done at desugaring
 
     def patternsOpt(location: Location = Location.InPattern): List[Tree] =

tests/pos/i24474.scala

@@ -0,0 +1,28 @@
+case class Foo(arg1: Int, arg2: Int)
+case class Bar(arg1: Int, arg2: Option[Int])
+
+object OK:
+  Foo(1, 2) match
+    case Foo(arg1 =
+    5
+    ) =>
+
+object Test:
+  Foo(1, 2) match
+    case Foo(arg1 =
+      5 // was: error: pattern expected
+    ) =>
+
+object Nest:
+  Bar(1, Option(2)) match
+    case Bar(arg2 =
+      Some(value =
+        42
+      )
+    ) =>
+
+object Detupled:
+  (fst = 1, snd = 2) match
+    case (fst =
+      5
+    ) =>