diff --git a/main-settings/src/main/scala/sbt/SlashSyntax.scala b/main-settings/src/main/scala/sbt/SlashSyntax.scala
index 0e512c487..93d31b1aa 100644
--- a/main-settings/src/main/scala/sbt/SlashSyntax.scala
+++ b/main-settings/src/main/scala/sbt/SlashSyntax.scala
@@ -50,18 +50,25 @@ trait SlashSyntax {
    */
   implicit def sbtSlashSyntaxRichScopeFromScoped(t: Scoped): RichScope =
     new RichScope(t.scope.copy(task = Select(t.key)))
+
+  implicit def sbtSlashSyntaxRichScopeFromAttributeKey(a: AttributeKey[_]): RichScope =
+    Scope(This, This, Select(a), This)
+
 }
 
 object SlashSyntax {
 
-  /** RichScopeLike wraps a general scope to provide the `/` operator for key scoping. */
-  sealed trait RichScopeLike {
+  sealed trait HasSlashKey {
     protected def scope: Scope
     final def /[K](key: Scoped.ScopingSetting[K]): K = key in scope
   }
 
+  sealed trait HasSlashKeyOrAttrKey extends HasSlashKey {
+    final def /(key: AttributeKey[_]): RichScope = new RichScope(scope in key)
+  }
+
   /** RichReference wraps a reference to provide the `/` operator for scoping. */
-  final class RichReference(protected val scope: Scope) extends RichScopeLike {
+  final class RichReference(protected val scope: Scope) extends HasSlashKeyOrAttrKey {
     def /(c: ConfigKey): RichConfiguration = new RichConfiguration(scope in c)
     def /(c: Configuration): RichConfiguration = new RichConfiguration(scope in c)
 
@@ -71,12 +78,13 @@ object SlashSyntax {
   }
 
   /** RichConfiguration wraps a configuration to provide the `/` operator for scoping. */
-  final class RichConfiguration(protected val scope: Scope) extends RichScopeLike {
+  final class RichConfiguration(protected val scope: Scope) extends HasSlashKeyOrAttrKey {
     // This is for handling `Zero / Zero / Zero / name`.
     def /(taskAxis: ScopeAxis[AttributeKey[_]]): RichScope =
       new RichScope(scope.copy(task = taskAxis))
   }
 
   /** RichScope wraps a general scope to provide the `/` operator for scoping. */
-  final class RichScope(protected val scope: Scope) extends RichScopeLike {}
+  final class RichScope(protected val scope: Scope) extends HasSlashKey
+
 }
diff --git a/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala b/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala
index 8a267f81a..93a2e77bb 100644
--- a/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala
+++ b/main-settings/src/test/scala/sbt/SlashSyntaxSpec.scala
@@ -148,6 +148,22 @@ object SlashSyntaxSpec extends Properties("SlashSyntax") with SlashSyntax {
     check[InputKey[String]] && check[SettingKey[String]] && check[TaskKey[String]]
   }
 
+  property("Reference / task.key / key == key in Reference in task") = {
+    def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
+      forAll((r: Reference, t: K, k: K) => expectValue(k in (r, t))(r / t.key / k))
+    (true
+        && check[InputKey[String], InputKey[String]]
+        && check[InputKey[String], SettingKey[String]]
+        && check[InputKey[String], TaskKey[String]]
+        && check[SettingKey[String], InputKey[String]]
+        && check[SettingKey[String], SettingKey[String]]
+        && check[SettingKey[String], TaskKey[String]]
+        && check[TaskKey[String], InputKey[String]]
+        && check[TaskKey[String], SettingKey[String]]
+        && check[TaskKey[String], TaskKey[String]]
+    )
+  }
+
   property("Reference / task / key ~= key in Reference in task") = {
     import WithoutScope._
     def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
@@ -165,6 +181,22 @@ object SlashSyntaxSpec extends Properties("SlashSyntax") with SlashSyntax {
     )
   }
 
+  property("Reference / Config / task.key / key == key in Reference in Config in task") = {
+    def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
+      forAll((r: Reference, c: ConfigKey, t: K, k: K) => expectValue(k in (r, c, t))(r / c / t.key / k))
+    (true
+        && check[InputKey[String], InputKey[String]]
+        && check[InputKey[String], SettingKey[String]]
+        && check[InputKey[String], TaskKey[String]]
+        && check[SettingKey[String], InputKey[String]]
+        && check[SettingKey[String], SettingKey[String]]
+        && check[SettingKey[String], TaskKey[String]]
+        && check[TaskKey[String], InputKey[String]]
+        && check[TaskKey[String], SettingKey[String]]
+        && check[TaskKey[String], TaskKey[String]]
+    )
+  }
+
   property("Reference / Config / task / key ~= key in Reference in Config in task") = {
     import WithoutScope._
     def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
@@ -188,6 +220,22 @@ object SlashSyntaxSpec extends Properties("SlashSyntax") with SlashSyntax {
     check[InputKey[String]] && check[SettingKey[String]] && check[TaskKey[String]]
   }
 
+  property("Config / task.key / key == key in Config in task") = {
+    def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
+      forAll((c: ConfigKey, t: K, k: K) => expectValue(k in c in t)(c / t.key / k))
+    (true
+        && check[InputKey[String], InputKey[String]]
+        && check[InputKey[String], SettingKey[String]]
+        && check[InputKey[String], TaskKey[String]]
+        && check[SettingKey[String], InputKey[String]]
+        && check[SettingKey[String], SettingKey[String]]
+        && check[SettingKey[String], TaskKey[String]]
+        && check[TaskKey[String], InputKey[String]]
+        && check[TaskKey[String], SettingKey[String]]
+        && check[TaskKey[String], TaskKey[String]]
+    )
+  }
+
   property("Config / task / key ~= key in Config in task") = {
     import WithoutScope._
     def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
@@ -205,6 +253,22 @@ object SlashSyntaxSpec extends Properties("SlashSyntax") with SlashSyntax {
     )
   }
 
+  property("task / key == key in task") = {
+    def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =
+      forAll((t: K, k: K) => expectValue(k in t)(t.key / k))
+    (true
+        && check[InputKey[String], InputKey[String]]
+        && check[InputKey[String], SettingKey[String]]
+        && check[InputKey[String], TaskKey[String]]
+        && check[SettingKey[String], InputKey[String]]
+        && check[SettingKey[String], SettingKey[String]]
+        && check[SettingKey[String], TaskKey[String]]
+        && check[TaskKey[String], InputKey[String]]
+        && check[TaskKey[String], SettingKey[String]]
+        && check[TaskKey[String], TaskKey[String]]
+    )
+  }
+
   property("task / key ~= key in task") = {
     import WithoutScope._
     def check[T <: Key[T]: Arbitrary, K <: Key[K]: Arbitrary] =