Merge pull request #2417 from paulp/pr/empty-type-bounds

Simplify type bounds.

3 files changed, 16 insertions, 28 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index a3abf633db..bd3af5f9a2 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -2222,16 +2222,18 @@ self =>
      *  }}}
      */
     def typeBounds(): TypeBoundsTree = {
-      val t = TypeBoundsTree(
-        bound(SUPERTYPE, tpnme.Nothing),
-        bound(SUBTYPE, tpnme.Any)
-      )
-      t setPos wrappingPos(List(t.hi, t.lo))
+      val lo      = bound(SUPERTYPE)
+      val hi      = bound(SUBTYPE)
+      val t       = TypeBoundsTree(lo, hi)
+      val defined = List(t.hi, t.lo) filter (_.pos.isDefined)
+
+      if (defined.nonEmpty)
+        t setPos wrappingPos(defined)
+      else
+        t setPos o2p(in.offset)
     }
 
-    def bound(tok: Int, default: TypeName): Tree =
-      if (in.token == tok) { in.nextToken(); typ() }
-      else atPos(o2p(in.lastOffset)) { rootScalaDot(default) }
+    def bound(tok: Int): Tree = if (in.token == tok) { in.nextToken(); typ() } else EmptyTree
 
 /* -------- DEFS ------------------------------------------- */
 
diff --git a/src/compiler/scala/tools/nsc/javac/JavaParsers.scala b/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
index f1b1d1a9a7..786754ce4c 100644
--- a/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
+++ b/src/compiler/scala/tools/nsc/javac/JavaParsers.scala
@@ -293,15 +293,8 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
         if (in.token == QMARK) {
           val pos = in.currentPos
           in.nextToken()
-          var lo: Tree = TypeTree(NothingClass.tpe)
-          var hi: Tree = TypeTree(AnyClass.tpe)
-          if (in.token == EXTENDS) {
-            in.nextToken()
-            hi = typ()
-          } else if (in.token == SUPER) {
-            in.nextToken()
-            lo = typ()
-          }
+          val hi = if (in.token == EXTENDS) { in.nextToken() ; typ() } else EmptyTree
+          val lo = if (in.token == SUPER)   { in.nextToken() ; typ() } else EmptyTree
           val tdef = atPos(pos) {
             TypeDef(
               Modifiers(Flags.JAVA | Flags.DEFERRED),
@@ -408,15 +401,8 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
     def typeParam(): TypeDef =
       atPos(in.currentPos) {
         val name = identForType()
-        val hi =
-          if (in.token == EXTENDS) {
-            in.nextToken()
-            bound()
-          } else {
-            scalaDot(tpnme.Any)
-          }
-        TypeDef(Modifiers(Flags.JAVA | Flags.DEFERRED | Flags.PARAM), name, List(),
-                TypeBoundsTree(scalaDot(tpnme.Nothing), hi))
+        val hi = if (in.token == EXTENDS) { in.nextToken() ; bound() } else EmptyTree
+        TypeDef(Modifiers(Flags.JAVA | Flags.DEFERRED | Flags.PARAM), name, Nil, TypeBoundsTree(EmptyTree, hi))
       }
 
     def bound(): Tree =
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 9536df888e..60b6248a07 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -5136,8 +5136,8 @@ trait Typers extends Adaptations with Tags {
       }
 
       def typedTypeBoundsTree(tree: TypeBoundsTree) = {
-        val lo1 = typedType(tree.lo, mode)
-        val hi1 = typedType(tree.hi, mode)
+        val lo1 = if (tree.lo.isEmpty) TypeTree(NothingTpe) else typedType(tree.lo, mode)
+        val hi1 = if (tree.hi.isEmpty) TypeTree(AnyTpe) else typedType(tree.hi, mode)
         treeCopy.TypeBoundsTree(tree, lo1, hi1) setType TypeBounds(lo1.tpe, hi1.tpe)
       }