Merge pull request #3563 from Duhemm/fix/3553

Fix #3553: Wrong generic sig. with singleton types

Author: allanrenucci

compiler/src/dotty/tools/dotc/transform/GenericSignatures.scala

@@ -56,7 +56,7 @@ object GenericSignatures {
       ps.foreach(boxedSig)
     }
 
-    def boxedSig(tp: Type): Unit = jsig(tp, primitiveOK = false)
+    def boxedSig(tp: Type): Unit = jsig(tp.widenDealias, primitiveOK = false)
 
     def boundsSig(bounds: List[Type]): Unit = {
       val (isTrait, isClass) = bounds partition (_.typeSymbol.is(Trait))

tests/pos/i3553.scala

@@ -0,0 +1,8 @@
+class Foo[T <: List[1]](param: List[1]) {
+  def foo(in: List[1]): List[true] = Nil
+  def bar[U >: List[1]](in: List['z']): List[1.0e9] = Nil
+}
+class Bar[T <: 1](param: 1) {
+  def foo(in: 1): true = true
+  def bar[U >: 1](in: 'z'): 1.0e9 = 1.0e9
+}