Expose a means to disable boolean settings

Enables `-Yboolean-setting:{true,false}`. This will be exploited
in the next commit to enable one to turn off a single component
of a group setting, such as `-Xlint` or `-optimize`.

3 files changed, 40 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/settings/MutableSettings.scala b/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
index 0536be92cf..a8421c8b15 100644
--- a/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
@@ -438,6 +438,17 @@ class MutableSettings(val errorFn: String => Unit)
     override def tryToSetFromPropertyValue(s : String) { // used from ide
       value = s.equalsIgnoreCase("true")
     }
+    override def tryToSetColon(args: List[String]) = args match {
+      case Nil => tryToSet(Nil)
+      case List(x) =>
+        if (x.equalsIgnoreCase("true")) {
+          value = true
+          Some(Nil)
+        } else if (x.equalsIgnoreCase("false")) {
+          value = false
+          Some(Nil)
+        } else errorAndValue("'" + x + "' is not a valid choice for '" + name + "'", None)
+    }
   }
 
   /** A special setting for accumulating arguments like -Dfoo=bar. */
diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
index a385a31165..57aa8243b6 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
@@ -20,7 +20,7 @@ trait ScalaSettings extends AbsScalaSettings
   self: MutableSettings =>
 
   /** Set of settings */
-  protected lazy val allSettings = mutable.HashSet[Setting]()
+  protected[scala] lazy val allSettings = mutable.HashSet[Setting]()
 
   /** Against my better judgment, giving in to martin here and allowing
    *  CLASSPATH to be used automatically.  So for the user-specified part
diff --git a/test/junit/scala/tools/nsc/settings/SettingsTest.scala b/test/junit/scala/tools/nsc/settings/SettingsTest.scala
new file mode 100644
index 0000000000..4b0e58ff79
--- /dev/null
+++ b/test/junit/scala/tools/nsc/settings/SettingsTest.scala
@@ -0,0 +1,28 @@
+package scala.tools.nsc
+package settings
+
+import org.junit.Assert._
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+import scala.tools.testing.AssertUtil.assertThrows
+
+@RunWith(classOf[JUnit4])
+class SettingsTest {
+  @Test def booleanSettingColon() {
+    def check(args: String*): MutableSettings#BooleanSetting = {
+      val s = new MutableSettings(msg => throw new IllegalArgumentException(msg))
+      val b1 = new s.BooleanSetting("-Ytest-setting", "")
+      s.allSettings += b1
+      val (ok, residual) = s.processArguments(args.toList, processAll = true)
+      assert(residual.isEmpty)
+      b1
+    }
+    assertTrue(check("-Ytest-setting").value)
+    assertTrue(check("-Ytest-setting:true").value)
+    assertTrue(check("-Ytest-setting:TRUE").value)
+    assertFalse(check("-Ytest-setting:false").value)
+    assertFalse(check("-Ytest-setting:FALSE").value)
+    assertThrows[IllegalArgumentException](check("-Ytest-setting:rubbish"))
+  }
+}