added @deprecatedName annotation, allowing to d...

added @deprecatedName annotation, allowing to deprecate parameter names.
review by prokopec.

5 files changed, 56 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Definitions.scala b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
index 1684b5f071..667bdd5386 100644
--- a/src/compiler/scala/tools/nsc/symtab/Definitions.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
@@ -136,6 +136,7 @@ trait Definitions extends reflect.generic.StandardDefinitions {
     lazy val ScalaObjectClass     = getClass("scala.ScalaObject")
     lazy val PartialFunctionClass = getClass("scala.PartialFunction")
     lazy val SymbolClass          = getClass("scala.Symbol")
+      lazy val Symbol_apply = getMember(SymbolClass.companionModule, nme.apply)
     lazy val StringClass          = getClass(sn.String)
     lazy val ClassClass           = getClass(sn.Class)
       def Class_getMethod = getMember(ClassClass, nme.getMethod_)
@@ -445,6 +446,7 @@ trait Definitions extends reflect.generic.StandardDefinitions {
     // special attributes
     lazy val SerializableAttr: Symbol = getClass("scala.serializable")
     lazy val DeprecatedAttr: Symbol = getClass("scala.deprecated")
+    lazy val DeprecatedNameAttr: Symbol = getClass("scala.deprecatedName")
     lazy val MigrationAnnotationClass: Symbol = getClass("scala.annotation.migration")
     lazy val BeanPropertyAttr: Symbol = getClass(sn.BeanProperty)
     lazy val BooleanBeanPropertyAttr: Symbol = getClass(sn.BooleanBeanProperty)
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index ed5f3b0e9a..71c4353834 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -694,7 +694,7 @@ trait Infer {
       val argtpes1 = argtpes map {
         case NamedType(name, tp) => // a named argument
           var res = tp
-          val pos = params.indexWhere(p => p.name == name && !p.hasFlag(SYNTHETIC))
+          val pos = params.indexWhere(p => (p.name == name || deprecatedName(p) == Some(name)) && !p.hasFlag(SYNTHETIC))
           if (pos == -1) {
             if (positionalAllowed) { // treat assignment as positional argument
               argPos(index) = index
diff --git a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
index 91fe113019..d783cf9c9f 100644
--- a/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/NamesDefaults.scala
@@ -410,7 +410,10 @@ trait NamesDefaults { self: Analyzer =>
     var positionalAllowed = true
     val namelessArgs = for ((arg, index) <- (args.zipWithIndex)) yield arg match {
       case a @ AssignOrNamedArg(Ident(name), rhs) =>
-        val pos = params.indexWhere(p => p.name == name && !p.hasFlag(SYNTHETIC))
+        val (pos, newName) = paramPos(params, name)
+        newName.foreach(n => {
+          typer.context.unit.deprecationWarning(arg.pos, "the parameter name "+ name +" has been deprecated. Use "+ n +" instead.")
+        })
         if (pos == -1) {
           if (positionalAllowed) {
             argPos(index) = index
@@ -482,4 +485,30 @@ trait NamesDefaults { self: Analyzer =>
       res = context.lookup(clazz.name.toTermName, clazz.owner)
     res
   }
+
+  /**
+   * Returns
+   *  - the position of the parameter named `name`
+   *  - optionally, if `name` is @deprecatedName, the new name
+   */
+  def paramPos(params: List[Symbol], name: Name): (Int, Option[Name]) = {
+    var i = 0
+    var rest = params
+    while (!rest.isEmpty) {
+      val p = rest.head
+      if (!p.hasFlag(SYNTHETIC)) {
+        if (p.name == name) return (i, None)
+        if (deprecatedName(p) == Some(name)) return (i, Some(p.name))
+      }
+      i += 1
+      rest = rest.tail
+    }
+    (-1, None)
+  }
+
+  def deprecatedName(sym: Symbol): Option[Name] =
+    sym.getAnnotation(DeprecatedNameAttr).map(ann => (ann.args(0): @unchecked) match {
+      case Apply(fun, Literal(str) :: Nil) if (fun.symbol == Symbol_apply) =>
+        newTermName(str.stringValue)
+    })
 }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 043c41fc10..770daccef0 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1758,6 +1758,16 @@ trait Typers { self: Analyzer =>
           meth.paramss.exists(ps => ps.exists(_.hasFlag(DEFAULTPARAM)) && isRepeatedParamType(ps.last.tpe)))
         error(meth.pos, "a parameter section with a `*'-parameter is not allowed to have default arguments")
 
+      if (phase.id <= currentRun.typerPhase.id) {
+        val allParams = meth.paramss.flatten
+        for (p <- allParams) {
+          deprecatedName(p).foreach(n => {
+            if (allParams.exists(p1 => p1.name == n || (p != p1 && deprecatedName(p1) == Some(n))))
+              error(p.pos, "deprecated parameter name "+ n +" has to be distinct from any other parameter name (deprecated or not).")
+          })
+        }
+      }
+
       checkMethodStructuralCompatible(meth)
 
       treeCopy.DefDef(ddef, typedMods, ddef.name, tparams1, vparamss1, tpt1, rhs1) setType NoType
diff --git a/src/library/scala/deprecatedName.scala b/src/library/scala/deprecatedName.scala
new file mode 100644
index 0000000000..30d0ae457a
--- /dev/null
+++ b/src/library/scala/deprecatedName.scala
@@ -0,0 +1,13 @@
+package scala
+
+import annotation.target._
+
+/**
+ * An annotation that designates the name of the parameter to which it is
+ * applied as deprecated. Using that name in a named argument generates
+ * a deprecation warning.
+ *
+ * @since 2.8.1
+ */
+@param
+class deprecatedName(name: Symbol) extends StaticAnnotation