Fixed bug in update method visibility which cau...

Fixed bug in update method visibility which caused x += y not to find
x's update method when defined generically. Closes #3278. Already
reviewed by odersky.

2 files changed, 46 insertions, 33 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/TreeInfo.scala b/src/compiler/scala/tools/nsc/ast/TreeInfo.scala
index 0f31a3a9f2..430967298c 100644
--- a/src/compiler/scala/tools/nsc/ast/TreeInfo.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreeInfo.scala
@@ -102,17 +102,20 @@ abstract class TreeInfo {
     case _ => false
   }
 
-  def isVariableOrGetter(tree: Tree) = tree match {
-    case Ident(_) =>
-      tree.symbol.isVariable
-    case Select(qual, _) =>
-      tree.symbol.isVariable ||
-      (mayBeVarGetter(tree.symbol) &&
-       tree.symbol.owner.info.member(nme.getterToSetter(tree.symbol.name)) != NoSymbol)
-    case Apply(Select(qual, nme.apply), _) =>
-      qual.tpe.member(nme.update) != NoSymbol
-    case _ =>
-      false
+  def isVariableOrGetter(tree: Tree) = {
+    def sym       = tree.symbol
+    def isVar     = sym.isVariable
+    def isGetter  = mayBeVarGetter(sym) && sym.owner.info.member(nme.getterToSetter(sym.name)) != NoSymbol
+
+    tree match {
+      case Ident(_)         => isVar
+      case Select(_, _)     => isVar || isGetter
+      case _                =>
+        methPart(tree) match {
+          case Select(qual, nme.apply)  => qual.tpe.member(nme.update) != NoSymbol
+          case _                        => false
+        }
+    }
   }
 
   /** Is tree a self constructor call?
@@ -295,10 +298,10 @@ abstract class TreeInfo {
   /** The method part of an application node
    */
   def methPart(tree: Tree): Tree = tree match {
-    case Apply(fn, _) => methPart(fn)
-    case TypeApply(fn, _) => methPart(fn)
+    case Apply(fn, _)           => methPart(fn)
+    case TypeApply(fn, _)       => methPart(fn)
     case AppliedTypeTree(fn, _) => methPart(fn)
-    case _ => tree
+    case _                      => tree
   }
 
   def firstArgument(tree: Tree): Tree = tree match {
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 0274dc8871..0311d3e53c 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -3334,31 +3334,41 @@ trait Typers { self: Analyzer =>
             Apply(
               Select(vble.duplicate, prefix) setPos fun.pos.focus, args) setPos tree.pos.makeTransparent
           ) setPos tree.pos
+
+        def mkUpdate(table: Tree, indices: List[Tree]) = {
+          gen.evalOnceAll(table :: indices, context.owner, context.unit) { ts =>
+            val tab = ts.head
+            val is = ts.tail
+            Apply(
+               Select(tab(), nme.update) setPos table.pos,
+               ((is map (i => i())) ::: List(
+                 Apply(
+                   Select(
+                     Apply(
+                       Select(tab(), nme.apply) setPos table.pos,
+                       is map (i => i())) setPos qual.pos,
+                     prefix) setPos fun.pos,
+                   args) setPos tree.pos)
+               )
+             ) setPos tree.pos
+           }
+        }
+
         val tree1 = qual match {
+          case Ident(_) =>
+            mkAssign(qual)
+
           case Select(qualqual, vname) =>
             gen.evalOnce(qualqual, context.owner, context.unit) { qq =>
               val qq1 = qq()
               mkAssign(Select(qq1, vname) setPos qual.pos)
             }
-          case Apply(Select(table, nme.apply), indices) =>
-            gen.evalOnceAll(table :: indices, context.owner, context.unit) { ts =>
-              val tab = ts.head
-              val is = ts.tail
-              Apply(
-                 Select(tab(), nme.update) setPos table.pos,
-                 ((is map (i => i())) ::: List(
-                   Apply(
-                     Select(
-                       Apply(
-                         Select(tab(), nme.apply) setPos table.pos,
-                         is map (i => i())) setPos qual.pos,
-                       prefix) setPos fun.pos,
-                     args) setPos tree.pos)
-                 )
-               ) setPos tree.pos
-             }
-           case Ident(_) =>
-             mkAssign(qual)
+
+          case Apply(fn, indices) =>
+            treeInfo.methPart(fn) match {
+              case Select(table, nme.apply) => mkUpdate(table, indices)
+              case _                        => errorTree(qual, "Unexpected tree during assignment conversion.")
+            }
         }
         typed1(tree1, mode, pt)
 /*