Merge pull request #4696 from dotty-staging/print-self-types

Print self types

Author: nicolasstucki

library/src/scala/tasty/util/ShowSourceCode.scala

@@ -146,14 +146,34 @@ class ShowSourceCode[T <: Tasty with Singleton](tasty0: T) extends Show[T](tasty
           case stat@Import(_, _) => stat
           case stat@Term() => stat
         }
-        if (stats1.nonEmpty) {
+
+        def printBody(printSelf: Boolean) = {
           this += " {"
           indented {
+            if (printSelf) {
+              val Some(ValDef(name, tpt, _)) = self
+              indented {
+                val name1 = if (name == "_") "this" else name
+                this += " " += name1 += ": "
+                printTypeTree(tpt)
+                this += " =>"
+              }
+            }
             this += lineBreak()
             printTrees(stats1, lineBreak())
           }
           this += lineBreak() += "}"
         }
+        self match {
+          case Some(ValDef(_, TypeTree.Singleton(_), _)) =>
+            if (stats1.nonEmpty)
+              printBody(printSelf = false)
+          case Some(ValDef(_, _, _)) =>
+            printBody(printSelf = true)
+          case _ =>
+            if (stats1.nonEmpty)
+              printBody(printSelf = false)
+        }
         this
 
       case tdef @ TypeDef(name, rhs) =>
@@ -875,10 +895,18 @@ class ShowSourceCode[T <: Tasty with Singleton](tasty0: T) extends Show[T](tasty
         printType(tp)
 
       case Type.ThisType(tp) =>
-        printType(tp)
         tp match {
-          case Type.SymRef(cdef @ ClassDef(_, _, _, _, _), _) if !cdef.flags.isObject => this += ".this"
-          case _ => this
+          case Type.SymRef(cdef @ ClassDef(name, _, _, _, _), prefix) if !cdef.flags.isObject =>
+            def printPrefix(prefix: TypeOrBounds): Unit = prefix match {
+              case Type.SymRef(ClassDef(name, _, _, _, _), prefix2) =>
+                printPrefix(prefix2)
+                this += name += "."
+              case _ =>
+            }
+            printPrefix(prefix)
+            this += name
+            this += ".this"
+          case _ => printType(tp)
         }
 
       case Type.TypeLambda(paramNames, tparams, body) =>

tests/pos/selftypes.decompiled

@@ -0,0 +1,12 @@
+/** Decompiled from out/posTestFromTasty/pos/selftypes/selftypes.class */
+object selftypes {
+  trait A() extends java.lang.Object { self: selftypes.AB =>
+    type AA = scala.List[this.BX]
+    class AX()
+  }
+  trait B() extends java.lang.Object { self: selftypes.AB =>
+    type BB = B.this.AA
+    class BX()
+  }
+  class AB() extends selftypes.A with selftypes.B
+}