Merge pull request scala#8528 from dotty-staging/fix-#8491

Fix scala#8491: Generate correct default getter names

Author: smarter

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

@@ -268,7 +268,7 @@ object desugar {
         Nil
     }
 
-    def normalizedVparamss = meth1.vparamss map (_ map (vparam =>
+    def normalizedVparamss = meth1.vparamss.map(_.map(vparam =>
       cpy.ValDef(vparam)(rhs = EmptyTree)))
 
     def defaultGetters(vparamss: List[List[ValDef]], n: Int): List[DefDef] = vparamss match {
@@ -290,7 +290,7 @@ object desugar {
         Nil
     }
 
-    val defGetters = defaultGetters(vparamss, 0)
+    val defGetters = defaultGetters(meth1.vparamss, 0)
     if (defGetters.isEmpty) meth1
     else {
       val meth2 = cpy.DefDef(meth1)(vparamss = normalizedVparamss)

tests/pos/i8491.scala

@@ -0,0 +1,6 @@
+trait Foo[A]; trait Bar
+
+object Test {
+  def qux1[A](implicit A: Foo[A], B: Bar = new Bar {}): Bar = B
+  def qux2[A: Foo](implicit B: Bar = new Bar {}): Bar = B
+}