PolyFunction desugar: Don't copy type flags to parameter (#16891)

odersky · web-flow · commit f177d96c919c · 2023-02-12T11:54:40.000+01:00
Fixes #16871
diff --git a/compiler/src/dotty/tools/dotc/ast/Desugar.scala b/compiler/src/dotty/tools/dotc/ast/Desugar.scala
@@ -1732,7 +1732,7 @@ object desugar {
 
           val applyVParams = vargs.zipWithIndex.map {
             case (p: ValDef, _) => p.withAddedFlags(mods.flags)
-            case (p, n) => makeSyntheticParameter(n + 1, p).withAddedFlags(mods.flags)
+            case (p, n) => makeSyntheticParameter(n + 1, p).withAddedFlags(mods.flags.toTermFlags)
           }
           RefinedTypeTree(polyFunctionTpt, List(
             DefDef(nme.apply, applyTParams :: applyVParams :: Nil, res, EmptyTree).withFlags(Synthetic)
diff --git a/tests/pos-custom-args/captures/i16871.scala b/tests/pos-custom-args/captures/i16871.scala
@@ -0,0 +1,3 @@
+import scala.language.experimental.captureChecking
+
+val f: [X] => Int => Int = [X] => (x: Int) => x

Original file line number	Diff line number	Diff line change
`@@ -1732,7 +1732,7 @@ object desugar {`
`1732`	`1732`
`1733`	`1733`	`val applyVParams = vargs.zipWithIndex.map {`
`1734`	`1734`	`case (p: ValDef, _) => p.withAddedFlags(mods.flags)`
`1735`		`- case (p, n) => makeSyntheticParameter(n + 1, p).withAddedFlags(mods.flags)`
	`1735`	`+ case (p, n) => makeSyntheticParameter(n + 1, p).withAddedFlags(mods.flags.toTermFlags)`
`1736`	`1736`	`}`
`1737`	`1737`	`RefinedTypeTree(polyFunctionTpt, List(`
`1738`	`1738`	`DefDef(nme.apply, applyTParams :: applyVParams :: Nil, res, EmptyTree).withFlags(Synthetic)`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+import scala.language.experimental.captureChecking`
	`2`	`+`
	`3`	`+val f: [X] => Int => Int = [X] => (x: Int) => x`