From c3e2a81b38133f2b997e56ccd85d9bea38896a6b Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Tue, 30 Oct 2012 07:43:03 -0700
Subject: Modification to SI-6534 patch.

Only exclude hashCode and equals from being overridden in
value classes, not other synthetics which may turn up such
as case class methods.
---
 .../tools/nsc/typechecker/SyntheticMethods.scala     | 20 +++++++++++---------
 test/files/neg/t6534.check                           |  5 ++++-
 test/files/neg/t6534.scala                           |  3 +++
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
index 0fda025972..903b5904d3 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
@@ -310,17 +310,19 @@ trait SyntheticMethods extends ast.TreeDSL {
        *  so they can appear in universal traits without breaking value semantics.
        */
       def impls = {
-        if (clazz.isDerivedValueClass)
-          for ((m, impl) <- methods) yield {
-            if (settings.lint.value)
-              (clazz.info nonPrivateMember m.name) filter (m => (m.owner != AnyClass) && (m.owner != clazz) && !m.isDeferred) andAlso { m =>
-                currentUnit.warning(clazz.pos, s"Implementation of ${m.name} inherited from ${m.owner} overridden in $clazz to enforce value class semantics")
+        def shouldGenerate(m: Symbol) = {
+          !hasOverridingImplementation(m) || {
+            clazz.isDerivedValueClass && (m == Any_hashCode || m == Any_equals) && {
+              if (settings.lint.value) {
+                (clazz.info nonPrivateMember m.name) filter (m => (m.owner != AnyClass) && (m.owner != clazz) && !m.isDeferred) andAlso { m =>
+                  currentUnit.warning(clazz.pos, s"Implementation of ${m.name} inherited from ${m.owner} overridden in $clazz to enforce value class semantics")
+                }
               }
-
-            impl()
+              true
+            }
           }
-        else
-          for ((m, impl) <- methods ; if !hasOverridingImplementation(m)) yield impl()
+        }
+        for ((m, impl) <- methods ; if shouldGenerate(m)) yield impl()
       }
       def extras = (
         if (needsReadResolve) {
diff --git a/test/files/neg/t6534.check b/test/files/neg/t6534.check
index bd7dc4b71c..52e70cfa8a 100644
--- a/test/files/neg/t6534.check
+++ b/test/files/neg/t6534.check
@@ -10,5 +10,8 @@ class Bippy3(val x: Int) extends AnyVal { override def equals(x: Any) = false }
 t6534.scala:7: error: redefinition of hashCode method. See SIP-15, criterion 4. is not allowed in value class
 class Bippy4(val x: Int) extends AnyVal { override def hashCode = -1 }          // error
                                                        ^
+t6534.scala:9: error: redefinition of equals method. See SIP-15, criterion 4. is not allowed in value class
+case class Bippy6(val x: Int) extends AnyVal { override def productPrefix = "Dingo" ; override def equals(x: Any) = false } // error
+                                                                                                   ^
 two warnings found
-two errors found
+three errors found
diff --git a/test/files/neg/t6534.scala b/test/files/neg/t6534.scala
index a193179399..de588b69a7 100644
--- a/test/files/neg/t6534.scala
+++ b/test/files/neg/t6534.scala
@@ -5,3 +5,6 @@ class Bippy1(val x: Int) extends AnyVal with Foo { }  // warn
 class Bippy2(val x: Int) extends AnyVal with Ding { } // warn
 class Bippy3(val x: Int) extends AnyVal { override def equals(x: Any) = false } // error
 class Bippy4(val x: Int) extends AnyVal { override def hashCode = -1 }          // error
+case class Bippy5(val x: Int) extends AnyVal { override def productPrefix = "Dingo" } // nothing
+case class Bippy6(val x: Int) extends AnyVal { override def productPrefix = "Dingo" ; override def equals(x: Any) = false } // error
+
-- 
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