From 35dbc88841e25ca70b68ac78d5b3e4ab0f23153c Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Wed, 29 Aug 2012 12:01:41 +0200
Subject: Closes SI-6227

I added some general hook where one can add validation code before a name conflict involving at least one implicit symbol is reported.
---
 src/compiler/scala/tools/nsc/typechecker/Namers.scala | 13 +++++++++++++
 test/files/neg/t6227.scala                            |  6 ++++++
 2 files changed, 19 insertions(+)
 create mode 100644 test/files/neg/t6227.scala

diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 77d1260564..adced9d8c9 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -192,6 +192,10 @@ trait Namers extends MethodSynthesis {
       if (!allowsOverload(sym)) {
         val prev = scope.lookupEntry(sym.name)
         if ((prev ne null) && prev.owner == scope && conflict(sym, prev.sym)) {
+          if (sym.isSynthetic || prev.sym.isSynthetic) {
+            handleSyntheticNameConflict(sym, prev.sym)
+            handleSyntheticNameConflict(prev.sym, sym)
+          }
           DoubleDefError(sym, prev.sym)
           sym setInfo ErrorType
           scope unlink prev.sym // let them co-exist...
@@ -202,6 +206,14 @@ trait Namers extends MethodSynthesis {
       scope enter sym
     }
 
+    /** Logic to handle name conflicts of synthetically generated symbols
+     *  We handle right now: t6227
+     */
+    def handleSyntheticNameConflict(sym1: Symbol, sym2: Symbol) = {
+      if (sym1.isImplicit && sym1.isMethod && sym2.isModule && sym2.companionClass.isCaseClass)
+        validate(sym2.companionClass)
+    }
+
     def enterSym(tree: Tree): Context = {
       def dispatch() = {
         var returnContext = this.context
@@ -1390,6 +1402,7 @@ trait Namers extends MethodSynthesis {
           fail(ImplicitAtToplevel)
       }
       if (sym.isClass) {
+        checkNoConflict(IMPLICIT, CASE)
         if (sym.isAnyOverride && !sym.hasFlag(TRAIT))
           fail(OverrideClass)
       } else {
diff --git a/test/files/neg/t6227.scala b/test/files/neg/t6227.scala
new file mode 100644
index 0000000000..46416839d1
--- /dev/null
+++ b/test/files/neg/t6227.scala
@@ -0,0 +1,6 @@
+object Test {
+  implicit case class IntOps( i: Int ) {
+    def twice = i * 2
+  }
+}
+
-- 
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