From bad61ce0ff9f460c2f8873c134a7f6bee0a53824 Mon Sep 17 00:00:00 2001
From: Som Snytt <som.snytt@gmail.com>
Date: Thu, 6 Apr 2017 18:13:22 -0700
Subject: SD-363 Xlint no warn deprecated params, defaults

Deprecation is an escape hatch for unused params.

Since default arg getters receive values of previous
args, don't warn when they are unused.
---
 .../scala/tools/nsc/typechecker/TypeDiagnostics.scala      | 14 ++++++++++----
 test/files/pos/t8040.scala                                 |  5 +++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala b/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala
index 7013c7da93..a0139937f1 100644
--- a/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala
@@ -567,10 +567,16 @@ trait TypeDiagnostics {
           && !treeTypes.exists(_ contains m)        // e.g. val a = new Foo ; new a.Bar
           //&& !(m.isVal && m.info.resultType =:= typeOf[Unit])      // Unit val is uninteresting
         )
-        def isUnusedParam(m: Symbol): Boolean = isUnusedTerm(m) && !(m.isParamAccessor && (
-          m.owner.isImplicit ||
-          targets.exists(s => s.isParameter && s.name == m.name && s.owner.isConstructor && s.owner.owner == m.owner) // exclude ctor params
-        ))
+        def isUnusedParam(m: Symbol): Boolean = (
+             isUnusedTerm(m)
+          && !m.isDeprecated
+          && !m.owner.isDefaultGetter
+          && !(m.isParamAccessor && (
+            m.owner.isImplicit ||
+            targets.exists(s => s.isParameter
+              && s.name == m.name && s.owner.isConstructor && s.owner.owner == m.owner) // exclude ctor params
+          ))
+        )
         def sympos(s: Symbol): Int =
           if (s.pos.isDefined) s.pos.point else if (s.isTerm) s.asTerm.referenced.pos.point else -1
         def treepos(t: Tree): Int =
diff --git a/test/files/pos/t8040.scala b/test/files/pos/t8040.scala
index 1d1a770060..3e01014ab4 100644
--- a/test/files/pos/t8040.scala
+++ b/test/files/pos/t8040.scala
@@ -5,4 +5,9 @@ object Test {
   }
 
   def f(implicit x: DummyImplicit) = 42                     // no warn DummyImplicit
+
+
+  def f(x: Int)(y: Int = 1) = x + y                         // no warn default getter
+
+  def g(@deprecated("","") x: Int) = 42                     // no warn deprecated
 }
-- 
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