SI-8525 No anonymous lint

Turn anonymous references to `settings.lint` into named settings.

After that, trust to Adriaan to make them filterable.

There are a few remaining top-level -Y lint warnings that are
deprecated.

16 files changed, 122 insertions, 40 deletions

diff --git a/src/compiler/scala/tools/nsc/plugins/Plugins.scala b/src/compiler/scala/tools/nsc/plugins/Plugins.scala
index 12f9aeba27..6e3d013e52 100644
--- a/src/compiler/scala/tools/nsc/plugins/Plugins.scala
+++ b/src/compiler/scala/tools/nsc/plugins/Plugins.scala
@@ -33,7 +33,7 @@ trait Plugins { global: Global =>
     }
     val maybes = Plugin.loadAllFrom(paths, dirs, settings.disable.value)
     val (goods, errors) = maybes partition (_.isSuccess)
-    // Explicit parameterization of recover to suppress -Xlint warning about inferred Any
+    // Explicit parameterization of recover to avoid -Xlint warning about inferred Any
     errors foreach (_.recover[Any] {
       // legacy behavior ignores altogether, so at least warn devs
       case e: MissingPluginException => if (global.isDeveloper) warning(e.getMessage)
diff --git a/src/compiler/scala/tools/nsc/settings/Warnings.scala b/src/compiler/scala/tools/nsc/settings/Warnings.scala
index f1ed45a2a0..3ff2369f86 100644
--- a/src/compiler/scala/tools/nsc/settings/Warnings.scala
+++ b/src/compiler/scala/tools/nsc/settings/Warnings.scala
@@ -34,34 +34,76 @@ trait Warnings {
     warnInferAny,
     // warnUnused       SI-7712, SI-7707 warnUnused not quite ready for prime-time
     // warnUnusedImport currently considered too noisy for general use
-    warnMissingInterpolator
+    // warnValueOverrides
+    warnMissingInterpolator,
+    warnDocDetached,
+    warnPrivateShadow,
+    warnPolyImplicitOverload,
+    warnOptionImplicit,
+    warnDelayedInit,
+    warnByNameRightAssociative,
+    warnPackageObjectClasses,
+    warnUnsoundMatch
   )
 
   private lazy val warnSelectNullable = BooleanSetting("-Xcheck-null", "This option is obsolete and does nothing.")
 
   // Individual warnings.
-  val warnAdaptedArgs      = BooleanSetting   ("-Ywarn-adapted-args", "Warn if an argument list is modified to match the receiver.")
-  val warnDeadCode         = BooleanSetting   ("-Ywarn-dead-code", "Warn when dead code is identified.")
-  val warnValueDiscard     = BooleanSetting   ("-Ywarn-value-discard", "Warn when non-Unit expression results are unused.")
-  val warnNumericWiden     = BooleanSetting   ("-Ywarn-numeric-widen", "Warn when numerics are widened.")
-  val warnNullaryUnit      = BooleanSetting   ("-Ywarn-nullary-unit", "Warn when nullary methods return Unit.")
-  val warnInaccessible     = BooleanSetting   ("-Ywarn-inaccessible", "Warn about inaccessible types in method signatures.")
-  val warnNullaryOverride  = BooleanSetting   ("-Ywarn-nullary-override", "Warn when non-nullary overrides nullary, e.g. `def foo()` over `def foo`.")
-  val warnInferAny         = BooleanSetting   ("-Ywarn-infer-any", "Warn when a type argument is inferred to be `Any`.")
-  val warnUnused           = BooleanSetting   ("-Ywarn-unused", "Warn when local and private vals, vars, defs, and types are are unused")
-  val warnUnusedImport     = BooleanSetting   ("-Ywarn-unused-import", "Warn when imports are unused")
+  val warnDeadCode         = BooleanSetting("-Ywarn-dead-code",
+                             "Warn when dead code is identified.")
+  val warnValueDiscard     = BooleanSetting("-Ywarn-value-discard",
+                             "Warn when non-Unit expression results are unused.")
+  val warnNumericWiden     = BooleanSetting("-Ywarn-numeric-widen",
+                             "Warn when numerics are widened.")
+  val warnUnused           = BooleanSetting("-Ywarn-unused",
+                             "Warn when local and private vals, vars, defs, and types are are unused")
+  val warnUnusedImport     = BooleanSetting("-Ywarn-unused-import",
+                             "Warn when imports are unused")
 
-  // Lint warnings that are not -Y
-  val warnMissingInterpolator = new BooleanSetting("warn-missing-interpolator", "Warn when a string literal appears to be missing an interpolator id.")
+  // Lint warnings that are not -Y, created with new instead of autoregistering factory method
+  private def lintflag(name: String, text: String) = new BooleanSetting(name, text)
+
+  val warnAdaptedArgs          = lintflag("adapted-args",
+                                 "Warn if an argument list is modified to match the receiver.")
+  val warnNullaryUnit          = lintflag("nullary-unit",
+                                 "Warn when nullary methods return Unit.")
+  val warnInaccessible         = lintflag("inaccessible",
+                                "Warn about inaccessible types in method signatures.")
+  val warnNullaryOverride      = lintflag("nullary-override",
+                                "Warn when non-nullary `def f()' overrides nullary `def f'.")
+  val warnInferAny             = lintflag("infer-any",
+                                "Warn when a type argument is inferred to be `Any`.")
+  val warnMissingInterpolator  = lintflag("missing-interpolator",
+                                "A string literal appears to be missing an interpolator id.")
+  val warnDocDetached          = lintflag("doc-detached",
+                                "A ScalaDoc comment appears to be detached from its element.")
+  val warnPrivateShadow        = lintflag("private-shadow",
+                                "A private field (or class parameter) shadows a superclass field.")
+  val warnPolyImplicitOverload = lintflag("poly-implicit-overload",
+                                "Parameterized overloaded implicit methods are not visible as view bounds")
+  val warnOptionImplicit       = lintflag("option-implicit",
+                                "Option.apply used implicit view.")
+  val warnDelayedInit          = lintflag("delayedinit-select",
+                                "Selecting member of DelayedInit")
+  val warnByNameRightAssociative = lintflag("by-name-right-associative",
+                                "By-name parameter of right associative operator")
+  val warnPackageObjectClasses = lintflag("package-object-classes",
+                                "Class or object defined in package object")
+  val warnUnsoundMatch         = lintflag("unsound-match",
+                                "Pattern match may not be typesafe")
+
+  // Lint warnings that are not enabled yet
+  val warnValueOverrides = lintflag("value-overrides", "Generated value class method overrides an implementation")
 
   // Warning groups.
   val lint                 = {
     // Boolean setting for testing if lint is on; not "added" to option processing
-    val xlint = new BooleanSetting("-Xlint", "Enable recommended additional warnings.")
-    def lintables = (lintWarnings map (_.name stripPrefix "-Y")).sorted
+    val xlint = lintflag("-Xlint", "Enable recommended additional warnings.")
+    val yprefix = "-Ywarn-"
+    def lintables = (lintWarnings map (_.name stripPrefix yprefix)).sorted
     def isAnon(b: BooleanSetting) = !(b.name startsWith "-")
     def setPolitely(b: BooleanSetting, v: Boolean) = if (!b.isSetByUser) b.value = v
-    def set(w: String, v: Boolean) = lintWarnings find (_.name.stripPrefix("-Y") == w) foreach (b => setPolitely(b, v))
+    def set(w: String, v: Boolean) = lintWarnings find (s => (s.name stripPrefix yprefix) == w) foreach (b => setPolitely(b, v))
     val Neg = "-"
     def propagate(ss: List[String]): Unit = ss match {
       case w :: rest => if (w startsWith Neg) set(w stripPrefix Neg, false) else set(w, true) ; propagate(rest)
@@ -81,6 +123,29 @@ trait Warnings {
     xlint
   }
 
+  // Lint warnings that are currently -Y, but deprecated in that usage
+  // Alas, the -Yarg must have a doppelgaenger that is not deprecated
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnAdaptedArgs      = BooleanSetting("-Ywarn-adapted-args",
+                             "Warn if an argument list is modified to match the receiver.") withDeprecationMessage
+                             "Enable -Xlint:adapted-args" enabling List(warnAdaptedArgs)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnNullaryUnit      = BooleanSetting("-Ywarn-nullary-unit",
+                             "Warn when nullary methods return Unit.") withDeprecationMessage
+                             "Enable -Xlint:nullary-unit" enabling List(warnNullaryUnit)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnInaccessible     = BooleanSetting("-Ywarn-inaccessible",
+                             "Warn about inaccessible types in method signatures.") withDeprecationMessage
+                             "Enable -Xlint:inaccessible" enabling List(warnInaccessible)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnNullaryOverride  = BooleanSetting("-Ywarn-nullary-override",
+                             "Warn when non-nullary `def f()' overrides nullary `def f'.") withDeprecationMessage
+                             "Enable -Xlint:nullary-override" enabling List(warnNullaryOverride)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnInferAny         = BooleanSetting("-Ywarn-infer-any",
+                             "Warn when a type argument is inferred to be `Any`.") withDeprecationMessage
+                             "Enable -Xlint:infer-any" enabling List(warnInferAny)
+
   // Backward compatibility.
   @deprecated("Use fatalWarnings", "2.11.0") def Xwarnfatal            = fatalWarnings      // used by sbt
   @deprecated("This option is being removed", "2.11.0") def Xchecknull = warnSelectNullable // used by ide
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala
index 6f81cbe152..b2dc6e4e52 100644
--- a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala
+++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala
@@ -50,7 +50,7 @@ trait TreeAndTypeAnalysis extends Debugging {
           // but the annotation didn't bubble up...
           // This is a pretty poor approximation.
           def unsoundAssumptionUsed = binder.name != nme.WILDCARD && !(pt <:< pat.tpe)
-          if (settings.lint && unsoundAssumptionUsed)
+          if (settings.warnUnsoundMatch && unsoundAssumptionUsed)
             reporter.warning(pat.pos,
               sm"""The value matched by $pat is bound to ${binder.name}, which may be used under the
                   |unsound assumption that it has type ${pat.tpe}, whereas we can only safely
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 1328119aac..7bbd81118a 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -717,7 +717,7 @@ trait Namers extends MethodSynthesis {
         m.updateAttachment(new ConstructorDefaultsAttachment(tree, null))
       }
       val owner = tree.symbol.owner
-      if (settings.lint && owner.isPackageObjectClass && !mods.isImplicit) {
+      if (settings.warnPackageObjectClasses && owner.isPackageObjectClass && !mods.isImplicit) {
         reporter.warning(tree.pos,
           "it is not recommended to define classes/objects inside of package objects.\n" +
           "If possible, define " + tree.symbol + " in " + owner.skipPackageObject + " instead."
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 1b3da26bf2..47465875e9 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -167,7 +167,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
       }
 
       // This has become noisy with implicit classes.
-      if (settings.lint && settings.developer) {
+      if (settings.warnPolyImplicitOverload && settings.developer) {
         clazz.info.decls filter (x => x.isImplicit && x.typeParams.nonEmpty) foreach { sym =>
           // implicit classes leave both a module symbol and a method symbol as residue
           val alts = clazz.info.decl(sym.name).alternatives filterNot (_.isModule)
@@ -954,7 +954,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
       def apply(tp: Type) = mapOver(tp).normalize
     }
 
-    def checkImplicitViewOptionApply(pos: Position, fn: Tree, args: List[Tree]): Unit = if (settings.lint) (fn, args) match {
+    def checkImplicitViewOptionApply(pos: Position, fn: Tree, args: List[Tree]): Unit = if (settings.warnOptionImplicit) (fn, args) match {
       case (tap@TypeApply(fun, targs), List(view: ApplyImplicitView)) if fun.symbol == currentRun.runDefinitions.Option_apply =>
         reporter.warning(pos, s"Suspicious application of an implicit view (${view.fun}) in the argument to Option.apply.") // SI-6567
       case _ =>
@@ -1320,7 +1320,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
         && !qual.tpe.isInstanceOf[ThisType]
         && sym.accessedOrSelf.isVal
       )
-      if (settings.lint.value && isLikelyUninitialized)
+      if (settings.warnDelayedInit && isLikelyUninitialized)
         reporter.warning(pos, s"Selecting ${sym} from ${sym.owner}, which extends scala.DelayedInit, is likely to yield an uninitialized value")
     }
 
@@ -1387,7 +1387,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
     private def checkByNameRightAssociativeDef(tree: DefDef) {
       tree match {
         case DefDef(_, name, _, params :: _, _, _) =>
-          if (settings.lint && !treeInfo.isLeftAssoc(name.decodedName) && params.exists(p => isByName(p.symbol)))
+          if (settings.warnByNameRightAssociative && !treeInfo.isLeftAssoc(name.decodedName) && params.exists(p => isByName(p.symbol)))
             reporter.warning(tree.pos,
               "by-name parameters will be evaluated eagerly when called as a right-associative infix operator. For more details, see SI-1980.")
         case _ =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index d3a41b9570..38b00a015b 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -247,7 +247,7 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
               // also exists in a superclass, because they may be surprised
               // to find out that a constructor parameter will shadow a
               // field. See SI-4762.
-              if (settings.lint) {
+              if (settings.warnPrivateShadow) {
                 if (sym.isPrivateLocal && sym.paramss.isEmpty) {
                   qual.symbol.ancestors foreach { parent =>
                     parent.info.decls filterNot (x => x.isPrivate || x.isLocalToThis) foreach { m2 =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
index 9516f94135..d0237fb468 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
@@ -339,12 +339,11 @@ trait SyntheticMethods extends ast.TreeDSL {
           !hasOverridingImplementation(m) || {
             clazz.isDerivedValueClass && (m == Any_hashCode || m == Any_equals) && {
               // Without a means to suppress this warning, I've thought better of it.
-              //
-              // if (settings.lint) {
-              //   (clazz.info nonPrivateMember m.name) filter (m => (m.owner != AnyClass) && (m.owner != clazz) && !m.isDeferred) andAlso { m =>
-              //     currentUnit.warning(clazz.pos, s"Implementation of ${m.name} inherited from ${m.owner} overridden in $clazz to enforce value class semantics")
-              //   }
-              // }
+              if (settings.warnValueOverrides) {
+                 (clazz.info nonPrivateMember m.name) filter (m => (m.owner != AnyClass) && (m.owner != clazz) && !m.isDeferred) andAlso { m =>
+                   currentUnit.warning(clazz.pos, s"Implementation of ${m.name} inherited from ${m.owner} overridden in $clazz to enforce value class semantics")
+                 }
+               }
               true
             }
           }
diff --git a/src/scaladoc/scala/tools/nsc/doc/ScaladocAnalyzer.scala b/src/scaladoc/scala/tools/nsc/doc/ScaladocAnalyzer.scala
index 10c382e169..ccf18b76de 100644
--- a/src/scaladoc/scala/tools/nsc/doc/ScaladocAnalyzer.scala
+++ b/src/scaladoc/scala/tools/nsc/doc/ScaladocAnalyzer.scala
@@ -190,7 +190,7 @@ abstract class ScaladocSyntaxAnalyzer[G <: Global](val global: G) extends Syntax
         typeParams.nonEmpty || version.nonEmpty || since.nonEmpty
       }
       def isDirty = unclean(unmooredParser parseComment doc)
-      if ((doc ne null) && (settings.lint || isDirty))
+      if ((doc ne null) && (settings.warnDocDetached || isDirty))
         reporter.warning(doc.pos, "discarding unmoored doc comment")
     }
 
diff --git a/test/files/neg/t4851.flags b/test/files/neg/t4851.flags
index ca0d0a0ba3..044ce22c84 100644
--- a/test/files/neg/t4851.flags
+++ b/test/files/neg/t4851.flags
@@ -1 +1 @@
--Ywarn-adapted-args -Xfatal-warnings -deprecation
+-Xlint:adapted-args -Xfatal-warnings -deprecation
diff --git a/test/files/neg/t8525.check b/test/files/neg/t8525.check
index 554ab23253..5287e43b7a 100644
--- a/test/files/neg/t8525.check
+++ b/test/files/neg/t8525.check
@@ -1,6 +1,15 @@
+t8525.scala:7: warning: Adapting argument list by creating a 2-tuple: this may not be what you want.
+        signature: X.f(p: (Int, Int)): Int
+  given arguments: 3, 4
+ after adaptation: X.f((3, 4): (Int, Int))
+  def g = f(3, 4)       // adapted
+           ^
 t8525.scala:9: warning: private[this] value name in class X shadows mutable name inherited from class Named.  Changes to name will not be visible within class X - you may want to give them distinct names.
   override def toString = name // shadowing mutable var name
                           ^
+t8525.scala:8: warning: side-effecting nullary methods are discouraged: suggest defining as `def u()` instead
+  def u: Unit = ()      // unitarian universalist
+      ^
 error: No warnings can be incurred under -Xfatal-warnings.
-one warning found
+three warnings found
 one error found
diff --git a/test/files/neg/t8525.flags b/test/files/neg/t8525.flags
index f19af1f717..53b2dfe7ec 100644
--- a/test/files/neg/t8525.flags
+++ b/test/files/neg/t8525.flags
@@ -1 +1 @@
--Xfatal-warnings -Xlint:-warn-missing-interpolator
+-Xfatal-warnings -Xlint:-missing-interpolator -Xlint
diff --git a/test/files/neg/t8610-arg.check b/test/files/neg/t8610-arg.check
index 4f194ce84a..ea2805508d 100644
--- a/test/files/neg/t8610-arg.check
+++ b/test/files/neg/t8610-arg.check
@@ -1,6 +1,12 @@
 t8610-arg.scala:5: warning: possible missing interpolator: detected interpolated identifier `$name`
   def x = "Hi, $name"   // missing interp
           ^
+t8610-arg.scala:7: warning: Adapting argument list by creating a 2-tuple: this may not be what you want.
+        signature: X.f(p: (Int, Int)): Int
+  given arguments: 3, 4
+ after adaptation: X.f((3, 4): (Int, Int))
+  def g = f(3, 4)       // adapted
+           ^
 t8610-arg.scala:9: warning: private[this] value name in class X shadows mutable name inherited from class Named.  Changes to name will not be visible within class X - you may want to give them distinct names.
   override def toString = name // shadowing mutable var name
                           ^
@@ -8,5 +14,5 @@ t8610-arg.scala:8: warning: side-effecting nullary methods are discouraged: sugg
   def u: Unit = ()      // unitarian universalist
       ^
 error: No warnings can be incurred under -Xfatal-warnings.
-three warnings found
+four warnings found
 one error found
diff --git a/test/files/neg/warn-inferred-any.flags b/test/files/neg/warn-inferred-any.flags
index a3127d392a..b580dfbbe3 100644
--- a/test/files/neg/warn-inferred-any.flags
+++ b/test/files/neg/warn-inferred-any.flags
@@ -1 +1 @@
--Xfatal-warnings -Ywarn-infer-any
+-Xfatal-warnings -Xlint:infer-any
diff --git a/test/files/run/t8610.check b/test/files/run/t8610.check
index 0e0dfc2cd3..fde82d5109 100644
--- a/test/files/run/t8610.check
+++ b/test/files/run/t8610.check
@@ -7,4 +7,7 @@ t8610.scala:6: warning: Adapting argument list by creating a 2-tuple: this may n
  after adaptation: X.f((3, 4): (Int, Int))
   def g = f(3, 4)       // adapted
            ^
+t8610.scala:7: warning: side-effecting nullary methods are discouraged: suggest defining as `def u()` instead
+  def u: Unit = ()      // unitarian universalist
+      ^
 Hi, $name
diff --git a/test/files/run/t8610.flags b/test/files/run/t8610.flags
index edcb5f4d0c..4195dec383 100644
--- a/test/files/run/t8610.flags
+++ b/test/files/run/t8610.flags
@@ -1 +1 @@
--Xlint:warn-adapted-args
+-Xlint:adapted-args
diff --git a/test/junit/scala/tools/nsc/settings/SettingsTest.scala b/test/junit/scala/tools/nsc/settings/SettingsTest.scala
index 29591727a3..9203054d9a 100644
--- a/test/junit/scala/tools/nsc/settings/SettingsTest.scala
+++ b/test/junit/scala/tools/nsc/settings/SettingsTest.scala
@@ -58,9 +58,9 @@ class SettingsTest {
   }
   @Test def anonymousLintersCanBeNamed() {
     assertTrue(check("-Xlint")(_.warnMissingInterpolator)) // among Xlint
-    assertFalse(check("-Xlint:-warn-missing-interpolator")(_.warnMissingInterpolator))
-    assertFalse(check("-Xlint:-warn-missing-interpolator", "-Xlint")(_.warnMissingInterpolator))
+    assertFalse(check("-Xlint:-missing-interpolator")(_.warnMissingInterpolator))
+    assertFalse(check("-Xlint:-missing-interpolator", "-Xlint")(_.warnMissingInterpolator))
     // two lint settings are first come etc; unlike -Y
-    assertTrue(check("-Xlint", "-Xlint:-warn-missing-interpolator")(_.warnMissingInterpolator))
+    assertTrue(check("-Xlint", "-Xlint:-missing-interpolator")(_.warnMissingInterpolator))
   }
 }