Merge pull request #1284 from retronym/topic/deprecated-inheritance

SI-6162 Adds private[scala] @deprecatedInheritance/@deprecatedOverriding

14 files changed, 129 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index dd4f13fd7b..f1f2794a95 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -430,6 +430,7 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R
             overrideError("cannot override a macro")
           } else {
             checkOverrideTypes()
+            checkOverrideDeprecated()
             if (settings.warnNullaryOverride.value) {
               if (other.paramss.isEmpty && !member.paramss.isEmpty) {
                 unit.warning(member.pos, "non-nullary method overrides nullary method")
@@ -508,6 +509,14 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R
             }
           }
         }
+        
+        def checkOverrideDeprecated() {
+          if (other.hasDeprecatedOverridingAnnotation) {
+            val suffix = other.deprecatedOverridingMessage map (": " + _) getOrElse ""
+            val msg = s"overriding ${other.fullLocationString} is deprecated$suffix"
+            unit.deprecationWarning(member.pos, msg)
+          }
+        }
       }
 
       val opc = new overridingPairs.Cursor(clazz)
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index a224c546e4..d48f5a4145 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1577,6 +1577,12 @@ trait Typers extends Modes with Adaptations with Tags {
           if (psym.isFinal)
             pending += ParentFinalInheritanceError(parent, psym)
 
+          if (psym.hasDeprecatedInheritanceAnnotation) {
+            val suffix = psym.deprecatedInheritanceMessage map (": " + _) getOrElse ""
+            val msg = s"inheritance from ${psym.fullLocationString} is deprecated$suffix"
+            unit.deprecationWarning(parent.pos, msg)
+          }
+
           if (psym.isSealed && !phase.erasedTypes)
             if (context.unit.source.file == psym.sourceFile)
               psym addChild context.owner
diff --git a/src/library/scala/deprecatedInheritance.scala b/src/library/scala/deprecatedInheritance.scala
new file mode 100644
index 0000000000..ca1b586223
--- /dev/null
+++ b/src/library/scala/deprecatedInheritance.scala
@@ -0,0 +1,22 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2012, LAMP/EPFL                  **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala
+
+/** An annotation that designates that inheriting from a class is deprecated.
+ *
+ *  This is usually done to warn about a non-final class being made final in a future version.
+ *  Sub-classing such a class then generates a warning.
+ *
+ *  @param  message the message to print during compilation if the class was sub-classed
+ *  @param  since   a string identifying the first version in which inheritance was deprecated
+ *  @since  2.10
+ *  @see    [[scala.deprecatedOverriding]]
+ */
+private[scala] // for now, this needs to be generalized to communicate other modifier deltas
+class deprecatedInheritance(message: String = "", since: String = "") extends annotation.StaticAnnotation
diff --git a/src/library/scala/deprecatedOverriding.scala b/src/library/scala/deprecatedOverriding.scala
new file mode 100644
index 0000000000..566cb59431
--- /dev/null
+++ b/src/library/scala/deprecatedOverriding.scala
@@ -0,0 +1,21 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2012, LAMP/EPFL                  **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+\*                                                                      */
+
+package scala
+
+/** An annotation that designates that overriding a member is deprecated.
+ *
+ *  Overriding such a member in  a sub-class then generates a warning.
+ *
+ *  @param  message the message to print during compilation if the member was overridden
+ *  @param  since   a string identifying the first version in which overriding was deprecated
+ *  @since  2.10
+ *  @see    [[scala.deprecatedInheritance]]
+ */
+private[scala] // for the same reasons as deprecatedInheritance
+class deprecatedOverriding(message: String = "", since: String = "") extends annotation.StaticAnnotation
diff --git a/src/library/scala/math/BigDecimal.scala b/src/library/scala/math/BigDecimal.scala
index 8669b2e2e8..a475d663f4 100644
--- a/src/library/scala/math/BigDecimal.scala
+++ b/src/library/scala/math/BigDecimal.scala
@@ -159,6 +159,7 @@ object BigDecimal {
  *  @author  Stephane Micheloud
  *  @version 1.0
  */
+@deprecatedInheritance("This class will me made final.", "2.10.0")
 class BigDecimal(
   val bigDecimal: BigDec,
   val mc: MathContext)
diff --git a/src/library/scala/math/BigInt.scala b/src/library/scala/math/BigInt.scala
index 09e8ae2026..e354117e14 100644
--- a/src/library/scala/math/BigInt.scala
+++ b/src/library/scala/math/BigInt.scala
@@ -114,6 +114,7 @@ object BigInt {
  *  @author  Martin Odersky
  *  @version 1.0, 15/07/2003
  */
+@deprecatedInheritance("This class will me made final.", "2.10.0")
 class BigInt(val bigInteger: BigInteger) extends ScalaNumber with ScalaNumericConversions with Serializable {
   /** Returns the hash code for this BigInt. */
   override def hashCode(): Int =
diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
index 4e44b76607..15b74058b7 100644
--- a/src/reflect/scala/reflect/internal/Definitions.scala
+++ b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -941,6 +941,8 @@ trait Definitions extends api.StandardDefinitions {
     lazy val CloneableAttr              = requiredClass[scala.annotation.cloneable]
     lazy val DeprecatedAttr             = requiredClass[scala.deprecated]
     lazy val DeprecatedNameAttr         = requiredClass[scala.deprecatedName]
+    lazy val DeprecatedInheritanceAttr  = requiredClass[scala.deprecatedInheritance]
+    lazy val DeprecatedOverridingAttr   = requiredClass[scala.deprecatedOverriding]
     lazy val NativeAttr                 = requiredClass[scala.native]
     lazy val RemoteAttr                 = requiredClass[scala.remote]
     lazy val ScalaInlineClass           = requiredClass[scala.inline]
diff --git a/src/reflect/scala/reflect/internal/Symbols.scala b/src/reflect/scala/reflect/internal/Symbols.scala
index 113500fe12..a1c774c545 100644
--- a/src/reflect/scala/reflect/internal/Symbols.scala
+++ b/src/reflect/scala/reflect/internal/Symbols.scala
@@ -697,6 +697,18 @@ trait Symbols extends api.Symbols { self: SymbolTable =>
     def deprecationMessage  = getAnnotation(DeprecatedAttr) flatMap (_ stringArg 0)
     def deprecationVersion  = getAnnotation(DeprecatedAttr) flatMap (_ stringArg 1)
     def deprecatedParamName = getAnnotation(DeprecatedNameAttr) flatMap (_ symbolArg 0)
+    def hasDeprecatedInheritanceAnnotation
+                            = hasAnnotation(DeprecatedInheritanceAttr)
+    def deprecatedInheritanceMessage
+                            = getAnnotation(DeprecatedInheritanceAttr) flatMap (_ stringArg 0)
+    def deprecatedInheritanceVersion
+                            = getAnnotation(DeprecatedInheritanceAttr) flatMap (_ stringArg 1)
+    def hasDeprecatedOverridingAnnotation
+                            = hasAnnotation(DeprecatedOverridingAttr)
+    def deprecatedOverridingMessage
+                            = getAnnotation(DeprecatedOverridingAttr) flatMap (_ stringArg 0)
+    def deprecatedOverridingVersion
+                            = getAnnotation(DeprecatedOverridingAttr) flatMap (_ stringArg 1)
 
     // !!! when annotation arguments are not literal strings, but any sort of
     // assembly of strings, there is a fair chance they will turn up here not as
diff --git a/test/files/neg/t6162-inheritance.check b/test/files/neg/t6162-inheritance.check
new file mode 100644
index 0000000000..a7d3cc3238
--- /dev/null
+++ b/test/files/neg/t6162-inheritance.check
@@ -0,0 +1,10 @@
+t6162-inheritance.scala:6: error: inheritance from class Foo in package t6126 is deprecated: `Foo` will be made final in a future version.
+class SubFoo extends Foo
+                     ^
+t6162-inheritance.scala:11: error: inheritance from trait T in package t6126 is deprecated
+object SubT extends T
+                    ^
+t6162-inheritance.scala:17: error: inheritance from trait S in package t6126 is deprecated
+  new S {
+      ^
+three errors found
diff --git a/test/files/neg/t6162-inheritance.flags b/test/files/neg/t6162-inheritance.flags
new file mode 100644
index 0000000000..65faf53579
--- /dev/null
+++ b/test/files/neg/t6162-inheritance.flags
@@ -0,0 +1 @@
+-Xfatal-warnings -deprecation
\ No newline at end of file
diff --git a/test/files/neg/t6162-inheritance.scala b/test/files/neg/t6162-inheritance.scala
new file mode 100644
index 0000000000..7b47b9285a
--- /dev/null
+++ b/test/files/neg/t6162-inheritance.scala
@@ -0,0 +1,19 @@
+package scala.t6126
+
+@deprecatedInheritance("`Foo` will be made final in a future version.", "2.10.0")
+class Foo
+
+class SubFoo extends Foo
+
+@deprecatedInheritance()
+trait T
+
+object SubT extends T
+
+@deprecatedInheritance()
+trait S
+
+object O {
+  new S {
+  }
+}
diff --git a/test/files/neg/t6162-overriding.check b/test/files/neg/t6162-overriding.check
new file mode 100644
index 0000000000..e774888d36
--- /dev/null
+++ b/test/files/neg/t6162-overriding.check
@@ -0,0 +1,7 @@
+t6162-overriding.scala:14: error: overriding method bar in class Bar is deprecated: `bar` will be made private in a future version.
+  override def bar = 43
+               ^
+t6162-overriding.scala:15: error: overriding method baz in class Bar is deprecated
+  override def baz = 43
+               ^
+two errors found
diff --git a/test/files/neg/t6162-overriding.flags b/test/files/neg/t6162-overriding.flags
new file mode 100644
index 0000000000..65faf53579
--- /dev/null
+++ b/test/files/neg/t6162-overriding.flags
@@ -0,0 +1 @@
+-Xfatal-warnings -deprecation
\ No newline at end of file
diff --git a/test/files/neg/t6162-overriding.scala b/test/files/neg/t6162-overriding.scala
new file mode 100644
index 0000000000..4cab0c2dee
--- /dev/null
+++ b/test/files/neg/t6162-overriding.scala
@@ -0,0 +1,17 @@
+package scala.t6162
+
+class Bar {
+  @deprecatedOverriding("`bar` will be made private in a future version.", "2.10.0")
+  def bar = 42
+
+  @deprecatedOverriding()
+  def baz = 42
+
+  def baz(a: Any) = 0
+}
+
+class SubBar extends Bar {
+  override def bar = 43
+  override def baz = 43
+  override def baz(a: Any) = 43 // okay
+}