From aca8f96d1cf5f645c24eac11f695dadae08ea381 Mon Sep 17 00:00:00 2001
From: Jason Zaugg <jzaugg@gmail.com>
Date: Fri, 1 May 2015 12:34:51 +1000
Subject: SI-9286 Check subclass privates for "same type after erasure"

The overriding pairs cursor used to detect erased signature clashes
was turning a blind eye to any pair that contained a private method.

However, this could lead to a `VerifyError` or `IllegalAccessError`.

Checking against javac's behaviour in both directions:

```
% cat sandbox/Test.java
public abstract class Test {
  class C { int foo() { return 0; } }
  class D extends C { private <A> int foo() { return 1; } }
}

% javac sandbox/Test.java
sandbox/Test.java:3: error: name clash: <A>foo() in Test.D and foo() in Test.C have the same erasure, yet neither overrides the other
  class D extends C { private <A> int foo() { return 1; } }
                                      ^
  where A is a type-variable:
    A extends Object declared in method <A>foo()
1 error
```

```
% cat sandbox/Test.java
public abstract class Test {
  class C { private int foo() { return 0; } }
  class D extends C { <A> int foo() { return 1; } }
}

% javac sandbox/Test.java
%
```

This commit only the exludes private symbols from the superclass
from the checks by moving the test from `excludes` to `matches`.
---
 src/compiler/scala/tools/nsc/transform/Erasure.scala | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala
index 9fdc3a9d72..a04625c9c5 100644
--- a/src/compiler/scala/tools/nsc/transform/Erasure.scala
+++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala
@@ -814,11 +814,10 @@ abstract class Erasure extends AddInterfaces
         // specialized members have no type history before 'specialize', causing double def errors for curried defs
         override def exclude(sym: Symbol): Boolean = (
              sym.isType
-          || sym.isPrivate
           || super.exclude(sym)
           || !sym.hasTypeAt(currentRun.refchecksPhase.id)
         )
-        override def matches(lo: Symbol, high: Symbol) = true
+        override def matches(lo: Symbol, high: Symbol) = !high.isPrivate
       }
       def isErasureDoubleDef(pair: SymbolPair) = {
         import pair._
-- 
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