SI-8398 - unused warning reports lazy val as a method

Compiler internals treat lazy vals as methods. Therefore, we need to have a special case for them when assembling the warning message.

Author: Konstantin Fedorov

src/compiler/scala/tools/nsc/typechecker/TypeDiagnostics.scala

@@ -532,7 +532,7 @@ trait TypeDiagnostics {
             if (sym.isDefaultGetter) "default argument"
             else if (sym.isConstructor) "constructor"
             else if (sym.isVar || sym.isGetter && sym.accessed.isVar) "var"
-            else if (sym.isVal || sym.isGetter && sym.accessed.isVal) "val"
+            else if (sym.isVal || sym.isGetter && sym.accessed.isVal || sym.isLazy) "val"
             else if (sym.isSetter) "setter"
             else if (sym.isMethod) "method"
             else if (sym.isModule) "object"

test/files/neg/warn-unused-privates.check

@@ -10,57 +10,60 @@ warn-unused-privates.scala:6: warning: private val in class Bippy is never used
 warn-unused-privates.scala:13: warning: private val in object Bippy is never used
   private val HEY_INSTANCE: Int = 1000    // warn
               ^
-warn-unused-privates.scala:35: warning: private val in class Boppy is never used
+warn-unused-privates.scala:14: warning: private val in object Bippy is never used
+  private lazy val BOOL: Boolean = true   // warn
+                   ^
+warn-unused-privates.scala:36: warning: private val in class Boppy is never used
   private val hummer = "def" // warn
               ^
-warn-unused-privates.scala:42: warning: private var in trait Accessors is never used
+warn-unused-privates.scala:43: warning: private var in trait Accessors is never used
   private var v1: Int = 0 // warn
               ^
-warn-unused-privates.scala:42: warning: private setter in trait Accessors is never used
+warn-unused-privates.scala:43: warning: private setter in trait Accessors is never used
   private var v1: Int = 0 // warn
               ^
-warn-unused-privates.scala:43: warning: private setter in trait Accessors is never used
+warn-unused-privates.scala:44: warning: private setter in trait Accessors is never used
   private var v2: Int = 0 // warn, never set
               ^
-warn-unused-privates.scala:44: warning: private var in trait Accessors is never used
+warn-unused-privates.scala:45: warning: private var in trait Accessors is never used
   private var v3: Int = 0 // warn, never got
               ^
-warn-unused-privates.scala:56: warning: private default argument in trait DefaultArgs is never used
+warn-unused-privates.scala:57: warning: private default argument in trait DefaultArgs is never used
   private def bippy(x1: Int, x2: Int = 10, x3: Int = 15): Int = x1 + x2 + x3
                              ^
-warn-unused-privates.scala:56: warning: private default argument in trait DefaultArgs is never used
+warn-unused-privates.scala:57: warning: private default argument in trait DefaultArgs is never used
   private def bippy(x1: Int, x2: Int = 10, x3: Int = 15): Int = x1 + x2 + x3
                                            ^
-warn-unused-privates.scala:67: warning: local var in method f0 is never used
+warn-unused-privates.scala:68: warning: local var in method f0 is never used
     var x = 1 // warn
         ^
-warn-unused-privates.scala:74: warning: local val in method f1 is never used
+warn-unused-privates.scala:75: warning: local val in method f1 is never used
     val b = new Outer // warn
         ^
-warn-unused-privates.scala:84: warning: private object in object Types is never used
+warn-unused-privates.scala:85: warning: private object in object Types is never used
   private object Dongo { def f = this } // warn
                  ^
-warn-unused-privates.scala:94: warning: local object in method l1 is never used
+warn-unused-privates.scala:95: warning: local object in method l1 is never used
     object HiObject { def f = this } // warn
            ^
-warn-unused-privates.scala:78: warning: local var x in method f2 is never set - it could be a val
+warn-unused-privates.scala:79: warning: local var x in method f2 is never set - it could be a val
     var x = 100 // warn about it being a var
         ^
-warn-unused-privates.scala:85: warning: private class Bar1 in object Types is never used
+warn-unused-privates.scala:86: warning: private class Bar1 in object Types is never used
   private class Bar1 // warn
                 ^
-warn-unused-privates.scala:87: warning: private type Alias1 in object Types is never used
+warn-unused-privates.scala:88: warning: private type Alias1 in object Types is never used
   private type Alias1 = String // warn
                ^
-warn-unused-privates.scala:95: warning: local class Hi is never used
+warn-unused-privates.scala:96: warning: local class Hi is never used
     class Hi { // warn
           ^
-warn-unused-privates.scala:99: warning: local class DingDongDoobie is never used
+warn-unused-privates.scala:100: warning: local class DingDongDoobie is never used
     class DingDongDoobie // warn
           ^
-warn-unused-privates.scala:102: warning: local type OtherThing is never used
+warn-unused-privates.scala:103: warning: local type OtherThing is never used
     type OtherThing = String // warn
          ^
 error: No warnings can be incurred under -Xfatal-warnings.
-21 warnings found
+22 warnings found
 one error found

test/files/neg/warn-unused-privates.scala

@@ -11,6 +11,7 @@ object Bippy {
   def hi(x: Bippy) = x.HI_COMPANION
   private val HI_INSTANCE: Int = 500      // no warn, accessed from instance
   private val HEY_INSTANCE: Int = 1000    // warn
+  private lazy val BOOL: Boolean = true   // warn
 }
 
 class A(val msg: String)