SI-7582 Only inline accessible calls to package-private Java code

Two problems here.

The inliner was using `isPrivate` / `isProtected` to determine access.
The fallthrough considered things to be (bytecode) public. This is okay
in practice for Scala code, which never emits package private code.

Secondly, we must check accessibility of the called symbol *and* its
owner. This case is tested in `run/t7582b`.

This commit tightens the check for Java defined symbols: a) check the owner,
and b) don't assume that `! isPrivate` is accessible.

9 files changed, 62 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala b/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
index a6eedbd07e..56191cc981 100644
--- a/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
+++ b/src/compiler/scala/tools/nsc/backend/opt/Inliners.scala
@@ -679,9 +679,18 @@ abstract class Inliners extends SubComponent {
         }
         */
 
-        def checkField(f: Symbol)   = check(f, f.isPrivate && !canMakePublic(f))
-        def checkSuper(n: Symbol)   = check(n, n.isPrivate || !n.isClassConstructor)
-        def checkMethod(n: Symbol)  = check(n, n.isPrivate)
+
+        def isPrivateForInlining(sym: Symbol): Boolean = {
+          if (sym.isJavaDefined) {
+            def check(sym: Symbol) = !(sym.isPublic || sym.isProtected)
+            check(sym) || check(sym.owner) // SI-7582 Must check the enclosing class *and* the symbol for Java.
+          }
+          else sym.isPrivate // Scala never emits package-private bytecode
+        }
+
+        def checkField(f: Symbol)   = check(f, isPrivateForInlining(f) && !canMakePublic(f))
+        def checkSuper(n: Symbol)   = check(n, isPrivateForInlining(n) || !n.isClassConstructor)
+        def checkMethod(n: Symbol)  = check(n, isPrivateForInlining(n))
 
         def getAccess(i: Instruction) = i match {
           case CALL_METHOD(n, SuperCall(_)) => checkSuper(n)
diff --git a/test/files/run/t7582.check b/test/files/run/t7582.check
new file mode 100644
index 0000000000..225fb1ace8
--- /dev/null
+++ b/test/files/run/t7582.check
@@ -0,0 +1,2 @@
+warning: there were 1 inliner warning(s); re-run with -Yinline-warnings for details
+2
diff --git a/test/files/run/t7582.flags b/test/files/run/t7582.flags
new file mode 100644
index 0000000000..1182725e86
--- /dev/null
+++ b/test/files/run/t7582.flags
@@ -0,0 +1 @@
+-optimize
\ No newline at end of file
diff --git a/test/files/run/t7582/InlineHolder.scala b/test/files/run/t7582/InlineHolder.scala
new file mode 100644
index 0000000000..a18b9effaa
--- /dev/null
+++ b/test/files/run/t7582/InlineHolder.scala
@@ -0,0 +1,16 @@
+package p1 {
+  object InlineHolder {
+    @inline def inlinable = p1.PackageProtectedJava.protectedMethod() + 1
+  }
+}
+
+object O {
+  @noinline
+  def x = p1.InlineHolder.inlinable
+}
+
+object Test {
+  def main(args: Array[String]) {
+    println(O.x)
+  }
+}
diff --git a/test/files/run/t7582/PackageProtectedJava.java b/test/files/run/t7582/PackageProtectedJava.java
new file mode 100644
index 0000000000..b7ea2a7676
--- /dev/null
+++ b/test/files/run/t7582/PackageProtectedJava.java
@@ -0,0 +1,6 @@
+package p1;
+
+// public class, protected method
+public class PackageProtectedJava {
+	static final int protectedMethod() { return 1; }
+}
diff --git a/test/files/run/t7582b.check b/test/files/run/t7582b.check
new file mode 100644
index 0000000000..225fb1ace8
--- /dev/null
+++ b/test/files/run/t7582b.check
@@ -0,0 +1,2 @@
+warning: there were 1 inliner warning(s); re-run with -Yinline-warnings for details
+2
diff --git a/test/files/run/t7582b.flags b/test/files/run/t7582b.flags
new file mode 100644
index 0000000000..1182725e86
--- /dev/null
+++ b/test/files/run/t7582b.flags
@@ -0,0 +1 @@
+-optimize
\ No newline at end of file
diff --git a/test/files/run/t7582b/InlineHolder.scala b/test/files/run/t7582b/InlineHolder.scala
new file mode 100644
index 0000000000..a18b9effaa
--- /dev/null
+++ b/test/files/run/t7582b/InlineHolder.scala
@@ -0,0 +1,16 @@
+package p1 {
+  object InlineHolder {
+    @inline def inlinable = p1.PackageProtectedJava.protectedMethod() + 1
+  }
+}
+
+object O {
+  @noinline
+  def x = p1.InlineHolder.inlinable
+}
+
+object Test {
+  def main(args: Array[String]) {
+    println(O.x)
+  }
+}
diff --git a/test/files/run/t7582b/PackageProtectedJava.java b/test/files/run/t7582b/PackageProtectedJava.java
new file mode 100644
index 0000000000..55a44b79f9
--- /dev/null
+++ b/test/files/run/t7582b/PackageProtectedJava.java
@@ -0,0 +1,6 @@
+package p1;
+
+// protected class, public method
+class PackageProtectedJava {
+	public static final int protectedMethod() { return 1; }
+}