Move AmbiguousNamedTupleAssignment check to Typer

Co-Authored-By: Nicolas Stucki <[email protected]>
Co-Authored-By: Oliver Bračevac <[email protected]>

Author: 3 people

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -1639,8 +1639,6 @@ object desugar {
       if ctx.mode.is(Mode.Type) then
         AppliedTypeTree(ref(defn.NamedTupleTypeRef), namesTuple :: tup :: Nil)
       else
-        if names.length == 1 && ctx.scope.lookup(names.head).is(Flags.Mutable) then
-          report.migrationWarning(AmbiguousNamedTupleAssignment(names.head, elemValues.head), tree.srcPos)
         Apply(
           Apply(
             TypeApply(

tests/pos/21681b.scala

@@ -0,0 +1,17 @@
+def test1() =
+  class Person:
+    def age: Int = ???
+    def age_=(x: Int): Unit = ???
+
+  val person = Person()
+  
+  (person.age = 29) // no warn (interpreted as `person.age_=(29)`)
+
+def test2() =
+  class Person:
+    var age: Int = 28
+
+  val person = Person()
+  
+  (person.age = 29) // no warn (interpreted as `person.age_=(29)`)
+

tests/warn/21681b.check

@@ -0,0 +1,7 @@
+-- [E203] Syntax Migration Warning: tests/warn/21681b.scala:4:2 --------------------------------------------------------
+4 |  (age = 29) // warn
+  |  ^^^^^^^^^^
+  |  Ambiguous syntax: this is interpreted as a named tuple with one element,
+  |  not as an assignment.
+  |
+  |  To assign a value, use curly braces: `{age = 29}`.

tests/warn/21681b.scala

@@ -0,0 +1,5 @@
+
+object Test:
+  var age: Int = 28
+  (age = 29) // warn
+