New unmangling for ExpandedName

Author: odersky

compiler/src/dotty/tools/dotc/core/NameKinds.scala

@@ -151,9 +151,27 @@ object NameKinds {
 
   val QualifiedName           = new QualifiedNameKind(QUALIFIED, ".")
   val FlattenedName           = new QualifiedNameKind(FLATTENED, "$")
-  val ExpandedName            = new QualifiedNameKind(EXPANDED, str.EXPAND_SEPARATOR)
   val TraitSetterName         = new QualifiedNameKind(TRAITSETTER, str.TRAIT_SETTER_SEPARATOR)
 
+  val ExpandedName = new QualifiedNameKind(EXPANDED, str.EXPAND_SEPARATOR) {
+    private val FalseSuper = "$$super".toTermName
+    private val FalseSuperLength = FalseSuper.length
+
+    override def unmangle(name: SimpleTermName): TermName = {
+      var i = name.lastIndexOfSlice(str.EXPAND_SEPARATOR)
+      if (i < 0) name
+      else {
+        // Hack to make super accessors from traits work. They would otherwise fail because of #765
+        // The problem is that in `x$$super$$plus` the expansion prefix needs to be `x`
+        // instead of `x$$super`.
+        if (i > FalseSuperLength && name.slice(i - FalseSuperLength, i) == FalseSuper)
+          i -= FalseSuper.length
+
+        apply(name.take(i).asTermName, name.drop(i + str.EXPAND_SEPARATOR.length).asSimpleName)
+      }
+    }
+  }
+
   val UniqueName = new UniqueNameKind("$") {
     override def mkString(underlying: TermName, info: ThisInfo) =
       if (underlying.isEmpty) "$" + info.num + "$" else super.mkString(underlying, info)

compiler/src/dotty/tools/dotc/core/NameOps.scala

@@ -151,17 +151,6 @@ object NameOps {
       name.rewrite { case ExpandedName(_, unexp) => unexp }
     }
 
-    def unexpandedNameOfMangled: N = likeTyped {
-      var idx = name.lastIndexOfSlice(nme.EXPAND_SEPARATOR)
-
-      // Hack to make super accessors from traits work. They would otherwise fail because of #765
-      // TODO: drop this once we have more robust name handling
-      if (idx > FalseSuperLength && name.slice(idx - FalseSuperLength, idx) == FalseSuper)
-        idx -= FalseSuper.length
-
-      if (idx < 0) name else (name drop (idx + nme.EXPAND_SEPARATOR.length))
-    }
-
     def expandedPrefix: N = likeTyped { name.exclude(ExpandedName) }
 
     def expandedPrefixOfMangled: N = {
@@ -170,15 +159,6 @@ object NameOps {
       likeTyped(name.take(idx))
     }
 
-    def unmangleExpandedName: N =
-      if (name.isSimple) {
-        val unmangled = unexpandedNameOfMangled
-        if (name eq unmangled) name
-        else likeTyped(
-          ExpandedName(expandedPrefixOfMangled.toTermName, unmangled.asSimpleName))
-      }
-      else name
-
     def implClassName: N = likeTyped(name ++ tpnme.IMPL_CLASS_SUFFIX)
 
     def errorName: N = likeTyped(name ++ nme.ERROR)
@@ -323,6 +303,23 @@ object NameOps {
 
     /** If name length exceeds allowable limit, replace part of it by hash */
     def compactified(implicit ctx: Context): TermName = termName(compactify(name.toString))
+
+    def unmangle(kind: NameKind): N = likeTyped {
+      name rewrite {
+        case unmangled: SimpleTermName =>
+          kind.unmangle(unmangled)
+        case ExpandedName(prefix, last) =>
+          kind.unmangle(last) rewrite {
+            case kernel: SimpleTermName =>
+              ExpandedName(prefix, kernel)
+          }
+      }
+    }
+
+    def unmangle(kinds: List[NameKind]): N = {
+      val unmangled = (name /: kinds)(_.unmangle(_))
+      if (unmangled eq name) name else unmangled.unmangle(kinds)
+    }
   }
 
   // needed???
@@ -442,26 +439,6 @@ object NameOps {
         case NO_NAME => primitivePostfixMethodName
         case name => name
       }
-
-    def unmangleSuperName: TermName =
-      if (name.isSimple && name.startsWith(str.SUPER_PREFIX))
-        SuperAccessorName(name.drop(str.SUPER_PREFIX.length).asTermName)
-      else name
-
-    def unmangle(kind: NameKind): TermName = name rewrite {
-      case unmangled: SimpleTermName =>
-        kind.unmangle(unmangled)
-      case ExpandedName(prefix, last) =>
-        kind.unmangle(last) rewrite {
-          case kernel: SimpleTermName =>
-            ExpandedName(prefix, kernel)
-        }
-    }
-
-    def unmangle(kinds: List[NameKind]): TermName = {
-      val unmangled = (name /: kinds)(_.unmangle(_))
-      if (unmangled eq name) name else unmangled.unmangle(kinds)
-    }
   }
 
   private final val FalseSuper = "$$super".toTermName

compiler/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala

@@ -9,7 +9,7 @@ import java.lang.Double.longBitsToDouble
 
 import Contexts._, Symbols._, Types._, Scopes._, SymDenotations._, Names._, NameOps._
 import StdNames._, Denotations._, NameOps._, Flags._, Constants._, Annotations._
-import NameKinds.Scala2MethodNameKinds
+import NameKinds.{Scala2MethodNameKinds, SuperAccessorName, ExpandedName}
 import dotty.tools.dotc.typer.ProtoTypes.{FunProtoTyped, FunProto}
 import util.Positions._
 import dotty.tools.dotc.ast.{tpd, Trees, untpd}, ast.tpd._
@@ -437,12 +437,12 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
         if (name == nme.TRAIT_CONSTRUCTOR) nme.CONSTRUCTOR
         else name.asTermName.unmangle(Scala2MethodNameKinds)
     }
-    if (flags is Scala2ExpandedName) {
-      name = name.unmangleExpandedName
+    if ((flags is Scala2ExpandedName) && name.isSimple) {
+      name = name.unmangle(ExpandedName)
       flags = flags &~ Scala2ExpandedName
     }
     if (flags is Scala2SuperAccessor) {
-      name = name.asTermName.unmangleSuperName
+      name = name.asTermName.unmangle(SuperAccessorName)
       flags = flags &~ Scala2SuperAccessor
     }