bazel syntax: rename SkylarkNestedSet to Depset

The new name matches the Bazel documentation, whereas
NestedSet is a Blaze internal. Also, it is shorter.

Also: tweak its class doc comment.
All other changes are mechanical.
PiperOrigin-RevId: 281824680
diff --git a/src/test/java/com/google/devtools/build/lib/packages/TypeTest.java b/src/test/java/com/google/devtools/build/lib/packages/TypeTest.java
index 120e644..12b9468 100644
--- a/src/test/java/com/google/devtools/build/lib/packages/TypeTest.java
+++ b/src/test/java/com/google/devtools/build/lib/packages/TypeTest.java
@@ -23,7 +23,7 @@
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.StarlarkList;
 import com.google.devtools.build.lib.syntax.Tuple;
 import com.google.devtools.build.lib.testutil.MoreAsserts;
@@ -277,9 +277,8 @@
 
   @Test
   public void testListDepsetConversion() throws Exception {
-    Object input = SkylarkNestedSet.of(
-        String.class,
-        NestedSetBuilder.create(Order.STABLE_ORDER, "a", "b", "c"));
+    Object input =
+        Depset.of(String.class, NestedSetBuilder.create(Order.STABLE_ORDER, "a", "b", "c"));
     Type.STRING_LIST.convert(input, null);
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java b/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java
index 9781f68..9de3830 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/cpp/SkylarkCcCommonTest.java
@@ -50,11 +50,11 @@
 import com.google.devtools.build.lib.rules.cpp.CcToolchainFeatures.VariableWithValue;
 import com.google.devtools.build.lib.rules.cpp.CcToolchainFeatures.WithFeatureSet;
 import com.google.devtools.build.lib.rules.cpp.CcToolchainVariables.StringValueParser;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Dict;
 import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.EvalUtils;
 import com.google.devtools.build.lib.syntax.Sequence;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.syntax.Starlark;
 import com.google.devtools.build.lib.syntax.StarlarkList;
 import com.google.devtools.build.lib.testutil.Scratch;
@@ -117,7 +117,7 @@
         ");");
 
     ConfiguredTarget r = getConfiguredTarget("//a:r");
-    SkylarkNestedSet allFiles = (SkylarkNestedSet) getMyInfoFromTarget(r).getValue("all_files");
+    Depset allFiles = (Depset) getMyInfoFromTarget(r).getValue("all_files");
     RuleContext ruleContext = getRuleContext(r);
     CcToolchainProvider toolchain =
         CppHelper.getToolchain(
@@ -161,8 +161,8 @@
         new SkylarkProvider.SkylarkKey(
             Label.create(r.getLabel().getPackageIdentifier(), "rule.bzl"), "CruleInfo");
     SkylarkInfo cruleInfo = (SkylarkInfo) r.get(key);
-    SkylarkNestedSet staticRuntimeLib = (SkylarkNestedSet) cruleInfo.getValue("static");
-    SkylarkNestedSet dynamicRuntimeLib = (SkylarkNestedSet) cruleInfo.getValue("dynamic");
+    Depset staticRuntimeLib = (Depset) cruleInfo.getValue("static");
+    Depset dynamicRuntimeLib = (Depset) cruleInfo.getValue("dynamic");
 
     assertThat(staticRuntimeLib.getSet(Artifact.class).toList()).isEmpty();
     assertThat(dynamicRuntimeLib.getSet(Artifact.class).toList()).isEmpty();
@@ -176,8 +176,8 @@
     invalidatePackages();
     r = getConfiguredTarget("//a:r");
     cruleInfo = (SkylarkInfo) r.get(key);
-    staticRuntimeLib = (SkylarkNestedSet) cruleInfo.getValue("static");
-    dynamicRuntimeLib = (SkylarkNestedSet) cruleInfo.getValue("dynamic");
+    staticRuntimeLib = (Depset) cruleInfo.getValue("static");
+    dynamicRuntimeLib = (Depset) cruleInfo.getValue("dynamic");
 
     RuleContext ruleContext = getRuleContext(r);
     CcToolchainProvider toolchain =
@@ -1119,7 +1119,7 @@
     StructImpl myInfo = getMyInfoFromTarget(getConfiguredTarget("//a:r"));
 
     List<Artifact> mergedHeaders =
-        ((SkylarkNestedSet) myInfo.getValue("merged_headers")).getSet(Artifact.class).toList();
+        ((Depset) myInfo.getValue("merged_headers")).getSet(Artifact.class).toList();
     assertThat(
             mergedHeaders.stream()
                 .map(Artifact::getFilename)
@@ -1127,28 +1127,24 @@
         .containsAtLeast("header.h", "dep1.h", "dep2.h");
 
     List<String> mergedDefines =
-        ((SkylarkNestedSet) myInfo.getValue("merged_defines")).getSet(String.class).toList();
+        ((Depset) myInfo.getValue("merged_defines")).getSet(String.class).toList();
     assertThat(mergedDefines).containsAtLeast("MYDEFINE", "DEP1", "DEP2");
     assertThat(mergedDefines).doesNotContain("LOCALDEP1");
 
     List<String> mergedSystemIncludes =
-        ((SkylarkNestedSet) myInfo.getValue("merged_system_includes"))
-            .getSet(String.class)
-            .toList();
+        ((Depset) myInfo.getValue("merged_system_includes")).getSet(String.class).toList();
     assertThat(mergedSystemIncludes).containsAtLeast("foo/bar", "a/dep1/baz", "a/dep2/qux");
 
     List<String> mergedIncludes =
-        ((SkylarkNestedSet) myInfo.getValue("merged_includes")).getSet(String.class).toList();
+        ((Depset) myInfo.getValue("merged_includes")).getSet(String.class).toList();
     assertThat(mergedIncludes).contains("baz/qux");
 
     List<String> mergedQuoteIncludes =
-        ((SkylarkNestedSet) myInfo.getValue("merged_quote_includes")).getSet(String.class).toList();
+        ((Depset) myInfo.getValue("merged_quote_includes")).getSet(String.class).toList();
     assertThat(mergedQuoteIncludes).contains("quux/abc");
 
     List<String> mergedFrameworkIncludes =
-        ((SkylarkNestedSet) myInfo.getValue("merged_framework_includes"))
-            .getSet(String.class)
-            .toList();
+        ((Depset) myInfo.getValue("merged_framework_includes")).getSet(String.class).toList();
     assertThat(mergedFrameworkIncludes).contains("fuux/fgh");
   }
 
@@ -1297,7 +1293,7 @@
     ConfiguredTarget a = getConfiguredTarget("//a:a");
     StructImpl info = ((StructImpl) getMyInfoFromTarget(a).getValue("info"));
 
-    SkylarkNestedSet librariesToLink = info.getValue("libraries_to_link", SkylarkNestedSet.class);
+    Depset librariesToLink = info.getValue("libraries_to_link", Depset.class);
     assertThat(
             librariesToLink.toCollection(LibraryToLink.class).stream()
                 .filter(x -> x.getStaticLibrary() != null)
@@ -1339,15 +1335,14 @@
         (Sequence<String>) info.getValue("user_link_flags", Sequence.class);
     assertThat(userLinkFlags.getImmutableList())
         .containsExactly("-la", "-lc2", "-DEP2_LINKOPT", "-lc1", "-lc2", "-DEP1_LINKOPT");
-    SkylarkNestedSet additionalInputs = info.getValue("additional_inputs", SkylarkNestedSet.class);
+    Depset additionalInputs = info.getValue("additional_inputs", Depset.class);
     assertThat(
             additionalInputs.toCollection(Artifact.class).stream()
                 .map(x -> x.getFilename())
                 .collect(ImmutableList.toImmutableList()))
         .containsExactly("b.lds", "d.lds");
     Collection<LibraryToLink> librariesToLink =
-        info.getValue("libraries_to_link", SkylarkNestedSet.class)
-            .toCollection(LibraryToLink.class);
+        info.getValue("libraries_to_link", Depset.class).toCollection(LibraryToLink.class);
     assertThat(
             librariesToLink.stream()
                 .filter(x -> x.getStaticLibrary() != null)
diff --git a/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java b/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java
index 087a09b..9d102cf 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/java/JavaSkylarkApiTest.java
@@ -32,8 +32,8 @@
 import com.google.devtools.build.lib.packages.SkylarkProvider.SkylarkKey;
 import com.google.devtools.build.lib.packages.StructImpl;
 import com.google.devtools.build.lib.rules.java.JavaRuleOutputJarsProvider.OutputJar;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Sequence;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.testutil.TestConstants;
 import com.google.devtools.build.lib.util.FileType;
 import java.util.ArrayList;
@@ -315,12 +315,10 @@
                 new SkylarkKey(
                     Label.parseAbsolute("//java/test:extension.bzl", ImmutableMap.of()), "result"));
 
-    SkylarkNestedSet transitiveRuntimeJars =
-        ((SkylarkNestedSet) info.getValue("transitive_runtime_jars"));
-    SkylarkNestedSet transitiveCompileTimeJars =
-        ((SkylarkNestedSet) info.getValue("transitive_compile_time_jars"));
-    SkylarkNestedSet compileJars = ((SkylarkNestedSet) info.getValue("compile_jars"));
-    SkylarkNestedSet fullCompileJars = ((SkylarkNestedSet) info.getValue("full_compile_jars"));
+    Depset transitiveRuntimeJars = ((Depset) info.getValue("transitive_runtime_jars"));
+    Depset transitiveCompileTimeJars = ((Depset) info.getValue("transitive_compile_time_jars"));
+    Depset compileJars = ((Depset) info.getValue("compile_jars"));
+    Depset fullCompileJars = ((Depset) info.getValue("full_compile_jars"));
     @SuppressWarnings("unchecked")
     Sequence<Artifact> sourceJars = ((Sequence<Artifact>) info.getValue("source_jars"));
     JavaRuleOutputJarsProvider outputs = ((JavaRuleOutputJarsProvider) info.getValue("outputs"));
@@ -1069,16 +1067,16 @@
         .containsExactly("com.google.process.stuff");
     assertThat(
             Iterables.transform(
-                ((SkylarkNestedSet) info.getValue("processor_classpath")).toCollection(),
+                ((Depset) info.getValue("processor_classpath")).toCollection(),
                 o -> ((Artifact) o).getFilename()))
         .containsExactly("libplugin.jar", "libplugin_dep.jar");
-    assertThat(((SkylarkNestedSet) info.getValue("transitive_class_jars")).toCollection())
+    assertThat(((Depset) info.getValue("transitive_class_jars")).toCollection())
         .hasSize(3); // from to_be_processed, dep, and export
-    assertThat(((SkylarkNestedSet) info.getValue("transitive_class_jars")).toCollection())
+    assertThat(((Depset) info.getValue("transitive_class_jars")).toCollection())
         .contains(info.getValue("class_jar"));
-    assertThat(((SkylarkNestedSet) info.getValue("transitive_source_jars")).toCollection())
+    assertThat(((Depset) info.getValue("transitive_source_jars")).toCollection())
         .hasSize(3); // from to_be_processed, dep, and export
-    assertThat(((SkylarkNestedSet) info.getValue("transitive_source_jars")).toCollection())
+    assertThat(((Depset) info.getValue("transitive_source_jars")).toCollection())
         .contains(info.getValue("source_jar"));
   }
 
@@ -1123,11 +1121,9 @@
                 new SkylarkKey(
                     Label.parseAbsolute("//java/test:extension.bzl", ImmutableMap.of()), "result"));
 
-    SkylarkNestedSet rawMyCompileJars = (SkylarkNestedSet) (info.getValue("compile_jars"));
-    SkylarkNestedSet rawMyTransitiveRuntimeJars =
-        (SkylarkNestedSet) (info.getValue("transitive_runtime_jars"));
-    SkylarkNestedSet rawMyTransitiveCompileTimeJars =
-        (SkylarkNestedSet) (info.getValue("transitive_compile_time_jars"));
+    Depset rawMyCompileJars = (Depset) info.getValue("compile_jars");
+    Depset rawMyTransitiveRuntimeJars = (Depset) info.getValue("transitive_runtime_jars");
+    Depset rawMyTransitiveCompileTimeJars = (Depset) info.getValue("transitive_compile_time_jars");
 
     NestedSet<Artifact> myCompileJars = rawMyCompileJars.getSet(Artifact.class);
     NestedSet<Artifact> myTransitiveRuntimeJars = rawMyTransitiveRuntimeJars.getSet(Artifact.class);
@@ -1379,7 +1375,7 @@
                 new SkylarkKey(
                     Label.parseAbsolute("//foo:extension.bzl", ImmutableMap.of()), "result"));
 
-    SkylarkNestedSet sourceJars = (SkylarkNestedSet) info.getValue("property");
+    Depset sourceJars = (Depset) info.getValue("property");
 
     assertThat(prettyArtifactNames(sourceJars.getSet(Artifact.class)))
         .containsExactly(
@@ -1412,7 +1408,7 @@
                 new SkylarkKey(
                     Label.parseAbsolute("//foo:extension.bzl", ImmutableMap.of()), "result"));
 
-    SkylarkNestedSet sourceJars = (SkylarkNestedSet) info.getValue("property");
+    Depset sourceJars = (Depset) info.getValue("property");
 
     assertThat(prettyArtifactNames(sourceJars.getSet(Artifact.class)))
         .containsExactly(
@@ -1445,7 +1441,7 @@
                 new SkylarkKey(
                     Label.parseAbsolute("//foo:extension.bzl", ImmutableMap.of()), "result"));
 
-    SkylarkNestedSet sourceJars = (SkylarkNestedSet) info.getValue("property");
+    Depset sourceJars = (Depset) info.getValue("property");
 
     assertThat(prettyArtifactNames(sourceJars.getSet(Artifact.class)))
         .containsExactly(
@@ -1478,7 +1474,7 @@
                 new SkylarkKey(
                     Label.parseAbsolute("//foo:extension.bzl", ImmutableMap.of()), "result"));
 
-    SkylarkNestedSet exports = (SkylarkNestedSet) (info.getValue("property"));
+    Depset exports = (Depset) info.getValue("property");
 
     assertThat(exports.getSet(Label.class))
         .containsExactly(Label.parseAbsolute("//foo:my_java_lib_b", ImmutableMap.of()));
@@ -2275,7 +2271,7 @@
     useConfiguration(
         "--javabase=//a:jvm", "--extra_toolchains=//a:all", "--platforms=//a:platform");
     ConfiguredTarget ct = getConfiguredTarget("//a:r");
-    SkylarkNestedSet files = (SkylarkNestedSet) ct.get("files");
+    Depset files = (Depset) ct.get("files");
     assertThat(prettyArtifactNames(files.toCollection(Artifact.class))).containsExactly("a/a.txt");
   }
 }
diff --git a/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java b/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java
index b612509..197af1d 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcProviderTest.java
@@ -25,7 +25,7 @@
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.rules.objc.ObjcProvider.Key;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.StarlarkSemantics;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.vfs.Root;
@@ -115,8 +115,7 @@
   public void directFieldsAddFromSkylark() throws Exception {
     ImmutableList<Artifact> artifacts =
         ImmutableList.of(createArtifact("/foo"), createArtifact("/bar"));
-    SkylarkNestedSet set =
-        SkylarkNestedSet.of(Artifact.class, NestedSetBuilder.wrap(Order.STABLE_ORDER, artifacts));
+    Depset set = Depset.of(Artifact.class, NestedSetBuilder.wrap(Order.STABLE_ORDER, artifacts));
     ObjcProvider.Builder builder = objcProviderBuilder();
     builder.addElementsFromSkylark(ObjcProvider.SOURCE, set);
     builder.addElementsFromSkylark(ObjcProvider.HEADER, set);
diff --git a/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcSkylarkTest.java b/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcSkylarkTest.java
index a487583..8765086 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcSkylarkTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/objc/ObjcSkylarkTest.java
@@ -30,8 +30,8 @@
 import com.google.devtools.build.lib.packages.StructImpl;
 import com.google.devtools.build.lib.rules.apple.AppleToolchain;
 import com.google.devtools.build.lib.rules.apple.DottedVersion;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Dict;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.syntax.StarlarkSemantics;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.List;
@@ -96,8 +96,8 @@
 
     ConfiguredTarget skylarkTarget = getConfiguredTarget("//examples/apple_skylark:my_target");
     StructImpl myInfo = getMyInfoFromTarget(skylarkTarget);
-    SkylarkNestedSet skylarkLibraries = (SkylarkNestedSet) myInfo.getValue("found_libs");
-    SkylarkNestedSet skylarkHdrs = (SkylarkNestedSet) myInfo.getValue("found_hdrs");
+    Depset skylarkLibraries = (Depset) myInfo.getValue("found_libs");
+    Depset skylarkHdrs = (Depset) myInfo.getValue("found_hdrs");
 
     assertThat(ActionsTestUtil.baseArtifactNames(skylarkLibraries.getSet(Artifact.class)))
         .contains("liblib.a");
@@ -137,7 +137,7 @@
 
     ConfiguredTarget skylarkTarget = getConfiguredTarget("//test:test");
     StructImpl myInfo = getMyInfoFromTarget(skylarkTarget);
-    SkylarkNestedSet defineSet = (SkylarkNestedSet) myInfo.getValue("define");
+    Depset defineSet = (Depset) myInfo.getValue("define");
 
     assertThat(defineSet.getSet(String.class)).containsExactly("mock_define");
   }
@@ -1089,8 +1089,7 @@
         "   srcs = ['a.m'],",
         ")");
     ConfiguredTarget skylarkTarget = getConfiguredTarget("//examples/apple_skylark:my_target");
-    SkylarkNestedSet emptyValue =
-        (SkylarkNestedSet) getMyInfoFromTarget(skylarkTarget).getValue("empty_value");
+    Depset emptyValue = (Depset) getMyInfoFromTarget(skylarkTarget).getValue("empty_value");
     assertThat(emptyValue.toCollection()).isEmpty();
   }
 
@@ -1127,8 +1126,7 @@
 
     ConfiguredTarget skylarkTarget = getConfiguredTarget("//examples/apple_skylark:my_target");
 
-    SkylarkNestedSet sdkFrameworks =
-        (SkylarkNestedSet) getMyInfoFromTarget(skylarkTarget).getValue("sdk_frameworks");
+    Depset sdkFrameworks = (Depset) getMyInfoFromTarget(skylarkTarget).getValue("sdk_frameworks");
     assertThat(sdkFrameworks.toCollection()).containsAtLeast("Accelerate", "GLKit");
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/rules/python/PyStructUtilsTest.java b/src/test/java/com/google/devtools/build/lib/rules/python/PyStructUtilsTest.java
index 8b141e8..c7c6aaa 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/python/PyStructUtilsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/python/PyStructUtilsTest.java
@@ -26,8 +26,8 @@
 import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.packages.StructImpl;
 import com.google.devtools.build.lib.packages.StructProvider;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.EvalException;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.testutil.FoundationTestCase;
 import com.google.devtools.build.lib.testutil.MoreAsserts.ThrowingRunnable;
 import com.google.devtools.build.lib.vfs.Root;
@@ -64,11 +64,11 @@
     Map<String, Object> fields = new LinkedHashMap<>();
     fields.put(
         PyStructUtils.TRANSITIVE_SOURCES,
-        SkylarkNestedSet.of(Artifact.class, NestedSetBuilder.emptySet(Order.COMPILE_ORDER)));
+        Depset.of(Artifact.class, NestedSetBuilder.emptySet(Order.COMPILE_ORDER)));
     fields.put(PyStructUtils.USES_SHARED_LIBRARIES, false);
     fields.put(
         PyStructUtils.IMPORTS,
-        SkylarkNestedSet.of(String.class, NestedSetBuilder.emptySet(Order.COMPILE_ORDER)));
+        Depset.of(String.class, NestedSetBuilder.emptySet(Order.COMPILE_ORDER)));
     fields.put(PyStructUtils.HAS_PY2_ONLY_SOURCES, false);
     fields.put(PyStructUtils.HAS_PY3_ONLY_SOURCES, false);
     fields.putAll(overrides);
@@ -105,8 +105,7 @@
     NestedSet<Artifact> sources = NestedSetBuilder.create(Order.COMPILE_ORDER, dummyArtifact);
     StructImpl info =
         makeStruct(
-            ImmutableMap.of(
-                PyStructUtils.TRANSITIVE_SOURCES, SkylarkNestedSet.of(Artifact.class, sources)));
+            ImmutableMap.of(PyStructUtils.TRANSITIVE_SOURCES, Depset.of(Artifact.class, sources)));
     assertThat(PyStructUtils.getTransitiveSources(info)).isSameInstanceAs(sources);
   }
 
@@ -129,8 +128,7 @@
     NestedSet<Artifact> sources = NestedSetBuilder.emptySet(Order.NAIVE_LINK_ORDER);
     StructImpl info =
         makeStruct(
-            ImmutableMap.of(
-                PyStructUtils.TRANSITIVE_SOURCES, SkylarkNestedSet.of(Artifact.class, sources)));
+            ImmutableMap.of(PyStructUtils.TRANSITIVE_SOURCES, Depset.of(Artifact.class, sources)));
     assertThrowsEvalExceptionContaining(
         () -> PyStructUtils.getTransitiveSources(info),
         "Incompatible depset order for 'transitive_sources': expected 'default' or 'postorder', "
@@ -160,8 +158,7 @@
   public void getImports_Good() throws Exception {
     NestedSet<String> imports = NestedSetBuilder.create(Order.COMPILE_ORDER, "abc");
     StructImpl info =
-        makeStruct(
-            ImmutableMap.of(PyStructUtils.IMPORTS, SkylarkNestedSet.of(String.class, imports)));
+        makeStruct(ImmutableMap.of(PyStructUtils.IMPORTS, Depset.of(String.class, imports)));
     assertThat(PyStructUtils.getImports(info)).isSameInstanceAs(imports);
   }
 
@@ -231,12 +228,12 @@
     // Assert using struct operations, not PyStructUtils accessors, which aren't necessarily trusted
     // to be correct.
     assertHasOrderAndContainsExactly(
-        ((SkylarkNestedSet) info.getValue(PyStructUtils.TRANSITIVE_SOURCES)).getSet(Artifact.class),
+        ((Depset) info.getValue(PyStructUtils.TRANSITIVE_SOURCES)).getSet(Artifact.class),
         Order.COMPILE_ORDER,
         dummyArtifact);
     assertThat((Boolean) info.getValue(PyStructUtils.USES_SHARED_LIBRARIES)).isTrue();
     assertHasOrderAndContainsExactly(
-        ((SkylarkNestedSet) info.getValue(PyStructUtils.IMPORTS)).getSet(String.class),
+        ((Depset) info.getValue(PyStructUtils.IMPORTS)).getSet(String.class),
         Order.COMPILE_ORDER,
         "abc");
     assertThat((Boolean) info.getValue(PyStructUtils.HAS_PY2_ONLY_SOURCES)).isTrue();
@@ -253,8 +250,7 @@
     // to be correct.
     assertThat((Boolean) info.getValue(PyStructUtils.USES_SHARED_LIBRARIES)).isFalse();
     assertHasOrderAndContainsExactly(
-        ((SkylarkNestedSet) info.getValue(PyStructUtils.IMPORTS)).getSet(String.class),
-        Order.COMPILE_ORDER);
+        ((Depset) info.getValue(PyStructUtils.IMPORTS)).getSet(String.class), Order.COMPILE_ORDER);
     assertThat((Boolean) info.getValue(PyStructUtils.HAS_PY2_ONLY_SOURCES)).isFalse();
     assertThat((Boolean) info.getValue(PyStructUtils.HAS_PY3_ONLY_SOURCES)).isFalse();
   }
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/trimming/TrimmableTestConfigurationFragments.java b/src/test/java/com/google/devtools/build/lib/skyframe/trimming/TrimmableTestConfigurationFragments.java
index 783b58b..c68f367 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/trimming/TrimmableTestConfigurationFragments.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/trimming/TrimmableTestConfigurationFragments.java
@@ -61,9 +61,9 @@
 import com.google.devtools.build.lib.rules.repository.WorkspaceBaseRule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.Printer;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.util.FileTypeSet;
 import com.google.devtools.common.options.Option;
@@ -679,8 +679,8 @@
           ToolchainInfo toolchainInfo = toolchainContext.forToolchainType(toolchainType);
           try {
             filesToBuild.addTransitive(
-                ((SkylarkNestedSet) toolchainInfo.getValue("files")).getSet(Artifact.class));
-          } catch (EvalException | SkylarkNestedSet.TypeException ex) {
+                ((Depset) toolchainInfo.getValue("files")).getSet(Artifact.class));
+          } catch (EvalException | Depset.TypeException ex) {
             throw new AssertionError(ex);
           }
         }
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkDefinedAspectsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkDefinedAspectsTest.java
index 5314287..12f75ae 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkDefinedAspectsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkDefinedAspectsTest.java
@@ -45,8 +45,8 @@
 import com.google.devtools.build.lib.rules.java.JavaConfiguration;
 import com.google.devtools.build.lib.rules.objc.ObjcProtoProvider;
 import com.google.devtools.build.lib.skyframe.AspectValue;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Sequence;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import java.util.Arrays;
 import org.junit.Before;
@@ -292,18 +292,18 @@
     ConfiguredAspect configuredAspect = aspectValue.getConfiguredAspect();
     assertThat(configuredAspect).isNotNull();
     Object names = configuredAspect.get("target_labels");
-    assertThat(names).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(names).isInstanceOf(Depset.class);
     assertThat(
             transform(
-                ((SkylarkNestedSet) names).toCollection(),
+                ((Depset) names).toCollection(),
                 o -> {
                   assertThat(o).isInstanceOf(Label.class);
                   return o.toString();
                 }))
         .containsExactly("//test:xxx", "//test:yyy");
     Object ruleKinds = configuredAspect.get("rule_kinds");
-    assertThat(ruleKinds).isInstanceOf(SkylarkNestedSet.class);
-    assertThat(((SkylarkNestedSet) ruleKinds).toCollection()).containsExactly("java_library");
+    assertThat(ruleKinds).isInstanceOf(Depset.class);
+    assertThat(((Depset) ruleKinds).toCollection()).containsExactly("java_library");
   }
 
   @Test
@@ -349,12 +349,14 @@
     ConfiguredAspect configuredAspect = aspectValue.getConfiguredAspect();
     assertThat(configuredAspect).isNotNull();
     Object nameSet = configuredAspect.get("target_labels");
-    ImmutableList<String> names = ImmutableList.copyOf(transform(
-        ((SkylarkNestedSet) nameSet).toCollection(),
-        o -> {
-          assertThat(o).isInstanceOf(Label.class);
-          return ((Label) o).getName();
-        }));
+    ImmutableList<String> names =
+        ImmutableList.copyOf(
+            transform(
+                ((Depset) nameSet).toCollection(),
+                o -> {
+                  assertThat(o).isInstanceOf(Label.class);
+                  return ((Label) o).getName();
+                }));
 
     assertThat(names).containsAtLeast("xxx", "yyy");
     // Third is the C++ toolchain; its name changes between Blaze and Bazel.
@@ -594,10 +596,10 @@
     assertThat(getLabelsToBuild(analysisResult)).containsExactly("//test:xxx");
     ConfiguredTarget target = analysisResult.getTargetsToBuild().iterator().next();
     Object names = target.get("rule_deps");
-    assertThat(names).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(names).isInstanceOf(Depset.class);
     assertThat(
             transform(
-                ((SkylarkNestedSet) names).toCollection(),
+                ((Depset) names).toCollection(),
                 o -> {
                   assertThat(o).isInstanceOf(Label.class);
                   return o.toString();
@@ -1640,7 +1642,7 @@
   private void buildTargetAndCheckRuleInfo(String... expectedLabels) throws Exception {
     AnalysisResult result = update(ImmutableList.<String>of(), "//test:r2");
     ConfiguredTarget configuredTarget = result.getTargetsToBuild().iterator().next();
-    SkylarkNestedSet ruleInfoValue = (SkylarkNestedSet) configuredTarget.get("rule_info");
+    Depset ruleInfoValue = (Depset) configuredTarget.get("rule_info");
     assertThat(ruleInfoValue.getSet(String.class))
         .containsExactlyElementsIn(Arrays.asList(expectedLabels));
   }
@@ -1712,8 +1714,7 @@
         "main_rule(name = 'main', deps = [':rbin', ':rgen'])");
     AnalysisResult analysisResult = update(ImmutableList.<String>of(), "//foo:main");
     ConfiguredTarget target = analysisResult.getTargetsToBuild().iterator().next();
-    NestedSet<Artifact> aspectFiles =
-        ((SkylarkNestedSet) target.get("aspect_files")).getSet(Artifact.class);
+    NestedSet<Artifact> aspectFiles = ((Depset) target.get("aspect_files")).getSet(Artifact.class);
     assertThat(transform(aspectFiles, Artifact::getFilename))
         .containsExactly("aspect-output-rbin", "aspect-output-rgen");
     for (Artifact aspectFile : aspectFiles) {
@@ -1900,10 +1901,10 @@
     ConfiguredAspect configuredAspect = aspectValue.getConfiguredAspect();
     assertThat(configuredAspect).isNotNull();
     Object names = configuredAspect.get("target_labels");
-    assertThat(names).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(names).isInstanceOf(Depset.class);
     assertThat(
             transform(
-                ((SkylarkNestedSet) names).toCollection(),
+                ((Depset) names).toCollection(),
                 o -> {
                   assertThat(o).isInstanceOf(Label.class);
                   return ((Label) o).getName();
@@ -2582,7 +2583,7 @@
     SkylarkKey pCollector =
         new SkylarkKey(Label.parseAbsolute("//test:aspect.bzl", ImmutableMap.of()), "PCollector");
     StructImpl collector = (StructImpl) configuredAspect.get(pCollector);
-    assertThat(((SkylarkNestedSet) collector.getValue("visited")).toCollection())
+    assertThat(((Depset) collector.getValue("visited")).toCollection())
         .containsExactly(
             Label.parseAbsolute("//test:referenced_from_aspect_only", ImmutableMap.of()),
             Label.parseAbsolute("//test:bar", ImmutableMap.of()),
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkIntegrationTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkIntegrationTest.java
index 433b989..91c8041 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkIntegrationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkIntegrationTest.java
@@ -55,8 +55,8 @@
 import com.google.devtools.build.lib.skyframe.PackageFunction;
 import com.google.devtools.build.lib.skyframe.SkyFunctions;
 import com.google.devtools.build.lib.skyframe.SkylarkImportLookupFunction;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Sequence;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.syntax.Starlark;
 import com.google.devtools.build.lib.syntax.StarlarkList;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -228,7 +228,7 @@
         OutputGroupInfo.get(getConfiguredTarget("//test/skylark:lib"))
             .getOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL);
     ConfiguredTarget myTarget = getConfiguredTarget("//test/skylark:my");
-    SkylarkNestedSet result = (SkylarkNestedSet) getMyInfoFromTarget(myTarget).getValue("result");
+    Depset result = (Depset) getMyInfoFromTarget(myTarget).getValue("result");
     assertThat(result.getSet(Artifact.class)).containsExactlyElementsIn(hiddenTopLevelArtifacts);
     assertThat(OutputGroupInfo.get(myTarget).getOutputGroup("my_group"))
         .containsExactlyElementsIn(hiddenTopLevelArtifacts);
@@ -254,7 +254,7 @@
         OutputGroupInfo.get(getConfiguredTarget("//test/skylark:lib"))
             .getOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL);
     ConfiguredTarget myTarget = getConfiguredTarget("//test/skylark:my");
-    SkylarkNestedSet result = (SkylarkNestedSet) getMyInfoFromTarget(myTarget).getValue("result");
+    Depset result = (Depset) getMyInfoFromTarget(myTarget).getValue("result");
     assertThat(result.getSet(Artifact.class)).containsExactlyElementsIn(hiddenTopLevelArtifacts);
     assertThat(OutputGroupInfo.get(myTarget).getOutputGroup("my_group"))
         .containsExactlyElementsIn(hiddenTopLevelArtifacts);
@@ -288,7 +288,7 @@
             .getOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL);
     ConfiguredTarget myTarget = getConfiguredTarget("//test/skylark:my");
     StructImpl myInfo = getMyInfoFromTarget(myTarget);
-    SkylarkNestedSet result = (SkylarkNestedSet) myInfo.getValue("result");
+    Depset result = (Depset) myInfo.getValue("result");
     assertThat(result.getSet(Artifact.class)).containsExactlyElementsIn(hiddenTopLevelArtifacts);
     assertThat(OutputGroupInfo.get(myTarget).getOutputGroup("my_group"))
         .containsExactlyElementsIn(hiddenTopLevelArtifacts);
@@ -322,7 +322,7 @@
         OutputGroupInfo.get(getConfiguredTarget("//test/skylark:lib"))
             .getOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL);
     ConfiguredTarget myTarget = getConfiguredTarget("//test/skylark:my");
-    SkylarkNestedSet result = (SkylarkNestedSet) getMyInfoFromTarget(myTarget).getValue("result");
+    Depset result = (Depset) getMyInfoFromTarget(myTarget).getValue("result");
     assertThat(result.getSet(Artifact.class)).containsExactlyElementsIn(hiddenTopLevelArtifacts);
     assertThat(OutputGroupInfo.get(myTarget).getOutputGroup("my_group"))
         .containsExactlyElementsIn(hiddenTopLevelArtifacts);
@@ -351,7 +351,7 @@
         OutputGroupInfo.get(getConfiguredTarget("//test/skylark:lib"))
             .getOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL);
     ConfiguredTarget myTarget = getConfiguredTarget("//test/skylark:my");
-    SkylarkNestedSet result = (SkylarkNestedSet) getMyInfoFromTarget(myTarget).getValue("result");
+    Depset result = (Depset) getMyInfoFromTarget(myTarget).getValue("result");
     assertThat(result.getSet(Artifact.class)).containsExactlyElementsIn(hiddenTopLevelArtifacts);
     assertThat(OutputGroupInfo.get(myTarget).getOutputGroup("my_group"))
         .containsExactlyElementsIn(hiddenTopLevelArtifacts);
@@ -380,7 +380,7 @@
         OutputGroupInfo.get(getConfiguredTarget("//test/skylark:lib"))
             .getOutputGroup(OutputGroupInfo.HIDDEN_TOP_LEVEL);
     ConfiguredTarget myTarget = getConfiguredTarget("//test/skylark:my");
-    SkylarkNestedSet result = (SkylarkNestedSet) getMyInfoFromTarget(myTarget).getValue("result");
+    Depset result = (Depset) getMyInfoFromTarget(myTarget).getValue("result");
     assertThat(result.getSet(Artifact.class)).containsExactlyElementsIn(hiddenTopLevelArtifacts);
     assertThat(OutputGroupInfo.get(myTarget).getOutputGroup("my_group"))
         .containsExactlyElementsIn(hiddenTopLevelArtifacts);
@@ -834,7 +834,7 @@
 
     assertThat(
             ActionsTestUtil.baseArtifactNames(
-                ((SkylarkNestedSet) getMyInfoFromTarget(target).getValue("provider_key"))
+                ((Depset) getMyInfoFromTarget(target).getValue("provider_key"))
                     .getSet(Artifact.class)))
         .containsExactly("a.txt");
   }
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
index ad00cd9..9d650c2 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleClassFunctionsTest.java
@@ -47,12 +47,12 @@
 import com.google.devtools.build.lib.skyframe.SkylarkImportLookupFunction;
 import com.google.devtools.build.lib.skylark.util.SkylarkTestCase;
 import com.google.devtools.build.lib.syntax.ClassObject;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Dict;
 import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.EvalUtils;
 import com.google.devtools.build.lib.syntax.Mutability;
 import com.google.devtools.build.lib.syntax.ParserInput;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.syntax.StarlarkFile;
 import com.google.devtools.build.lib.syntax.StarlarkList;
 import com.google.devtools.build.lib.syntax.SyntaxError;
@@ -1260,7 +1260,7 @@
   @Test
   public void testNsetGoodCompositeItem() throws Exception {
     exec("def func():", "  return depset([struct(a='a')])", "s = func()");
-    Collection<?> result = ((SkylarkNestedSet) lookup("s")).toCollection();
+    Collection<?> result = ((Depset) lookup("s")).toCollection();
     assertThat(result).hasSize(1);
     assertThat(result.iterator().next()).isInstanceOf(StructImpl.class);
   }
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java
index fb134dd..83b6949 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleContextTest.java
@@ -47,10 +47,10 @@
 import com.google.devtools.build.lib.rules.java.JavaSourceJarsProvider;
 import com.google.devtools.build.lib.rules.python.PyProviderUtils;
 import com.google.devtools.build.lib.skylark.util.SkylarkTestCase;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.Dict;
 import com.google.devtools.build.lib.syntax.Mutability;
 import com.google.devtools.build.lib.syntax.Sequence;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.syntax.Starlark;
 import com.google.devtools.build.lib.syntax.StarlarkList;
 import com.google.devtools.build.lib.testutil.TestRuleClassProvider;
@@ -1924,8 +1924,8 @@
     update("action1", eval("ruleContext.attr.dep[Actions].by_file[file1]"));
     update("action2", eval("ruleContext.attr.dep[Actions].by_file[file2]"));
 
-    assertThat(eval("action1.inputs")).isInstanceOf(SkylarkNestedSet.class);
-    assertThat(eval("action1.outputs")).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(eval("action1.inputs")).isInstanceOf(Depset.class);
+    assertThat(eval("action1.outputs")).isInstanceOf(Depset.class);
 
     assertThat(eval("action1.argv")).isEqualTo(Starlark.NONE);
     assertThat(eval("action2.content")).isEqualTo(Starlark.NONE);
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
index 83d6fec..e6615d0 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
@@ -58,11 +58,11 @@
 import com.google.devtools.build.lib.skylarkinterface.Param;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkGlobalLibrary;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.EvalException;
 import com.google.devtools.build.lib.syntax.EvalUtils;
 import com.google.devtools.build.lib.syntax.Printer;
 import com.google.devtools.build.lib.syntax.Sequence;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import com.google.devtools.build.lib.syntax.Starlark;
 import com.google.devtools.build.lib.syntax.StarlarkList;
 import com.google.devtools.build.lib.syntax.StarlarkThread;
@@ -750,7 +750,7 @@
         "    executable = 'dummy',",
         ")");
     assertArtifactFilenames(
-        ((SkylarkNestedSet) lookup("inputs")).getSet(Artifact.class),
+        ((Depset) lookup("inputs")).getSet(Artifact.class),
         "mytool.sh",
         "mytool",
         "foo_Smytool" + OsUtils.executableExtension() + "-runfiles",
@@ -992,7 +992,7 @@
   public void testFilesForRuleConfiguredTarget() throws Exception {
     setRuleContext(createRuleContext("//foo:foo"));
     Object result = eval("ruleContext.attr.srcs[0].files");
-    assertThat(ActionsTestUtil.baseNamesOf(((SkylarkNestedSet) result).getSet(Artifact.class)))
+    assertThat(ActionsTestUtil.baseNamesOf(((Depset) result).getSet(Artifact.class)))
         .isEqualTo("a.txt");
   }
 
@@ -1072,7 +1072,7 @@
         .containsExactly(
             "File:[/workspace[source]]test/run.file", "File:[/workspace[source]]test/run2.file");
 
-    assertThat(myInfo.getValue("rule_files")).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(myInfo.getValue("rule_files")).isInstanceOf(Depset.class);
     assertThat(myInfo.getValue("rule_files_to_run")).isInstanceOf(FilesToRunProvider.class);
     assertThat(myInfo.getValue("rule_file_executable")).isEqualTo(Starlark.NONE);
   }
@@ -1152,7 +1152,7 @@
         .containsExactly(
             "File:[/workspace[source]]test/run.file", "File:[/workspace[source]]test/run2.file");
 
-    assertThat(myInfo.getValue("rule_files")).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(myInfo.getValue("rule_files")).isInstanceOf(Depset.class);
     assertThat(myInfo.getValue("rule_files_to_run")).isInstanceOf(FilesToRunProvider.class);
   }
 
@@ -1243,7 +1243,7 @@
                 String::valueOf))
         .isEmpty();
 
-    assertThat(myInfo.getValue("file_files")).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(myInfo.getValue("file_files")).isInstanceOf(Depset.class);
     assertThat(myInfo.getValue("file_files_to_run")).isInstanceOf(FilesToRunProvider.class);
   }
 
@@ -1796,7 +1796,7 @@
   public void testFilesForFileConfiguredTarget() throws Exception {
     setRuleContext(createRuleContext("//foo:bar"));
     Object result = eval("ruleContext.attr.srcs[0].files");
-    assertThat(ActionsTestUtil.baseNamesOf(((SkylarkNestedSet) result).getSet(Artifact.class)))
+    assertThat(ActionsTestUtil.baseNamesOf(((Depset) result).getSet(Artifact.class)))
         .isEqualTo("libjl.jar");
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/skylarkdebug/server/DebuggerSerializationTest.java b/src/test/java/com/google/devtools/build/lib/skylarkdebug/server/DebuggerSerializationTest.java
index 4570ccb..74707f3 100644
--- a/src/test/java/com/google/devtools/build/lib/skylarkdebug/server/DebuggerSerializationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylarkdebug/server/DebuggerSerializationTest.java
@@ -26,9 +26,9 @@
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkPrinter;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
+import com.google.devtools.build.lib.syntax.Depset;
 import com.google.devtools.build.lib.syntax.EvalUtils;
 import com.google.devtools.build.lib.syntax.Printer;
-import com.google.devtools.build.lib.syntax.SkylarkNestedSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -61,8 +61,7 @@
   @Test
   public void testSimpleNestedSet() {
     Set<String> children = ImmutableSet.of("a", "b");
-    SkylarkNestedSet set =
-        SkylarkNestedSet.of(Object.class, NestedSetBuilder.stableOrder().addAll(children).build());
+    Depset set = Depset.of(Object.class, NestedSetBuilder.stableOrder().addAll(children).build());
 
     Value value = getValueProto("name", set);
 
@@ -89,8 +88,8 @@
     NestedSet<String> innerNestedSet =
         NestedSetBuilder.<String>stableOrder().add("inner1").add("inner2").build();
     ImmutableSet<String> directChildren = ImmutableSet.of("a", "b");
-    SkylarkNestedSet outerSet =
-        SkylarkNestedSet.of(
+    Depset outerSet =
+        Depset.of(
             String.class,
             NestedSetBuilder.<String>linkOrder()
                 .addAll(directChildren)
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkNestedSetTest.java b/src/test/java/com/google/devtools/build/lib/syntax/DepsetTest.java
similarity index 88%
rename from src/test/java/com/google/devtools/build/lib/syntax/SkylarkNestedSetTest.java
rename to src/test/java/com/google/devtools/build/lib/syntax/DepsetTest.java
index ea49524..1047dbd 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkNestedSetTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/DepsetTest.java
@@ -28,16 +28,14 @@
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
-/**
- * Tests for SkylarkNestedSet.
- */
+/** Tests for Depset. */
 @RunWith(JUnit4.class)
-public class SkylarkNestedSetTest extends EvaluationTestCase {
+public class DepsetTest extends EvaluationTestCase {
 
   @Test
   public void testConstructor() throws Exception {
     exec("s = depset(order='default')");
-    assertThat(lookup("s")).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(lookup("s")).isInstanceOf(Depset.class);
   }
 
   @Test
@@ -72,7 +70,7 @@
     exec("s = depset(['a', 'b'])");
     assertThat(get("s").getSet(String.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").getSet(Object.class)).containsExactly("a", "b").inOrder();
-    assertThrows(SkylarkNestedSet.TypeException.class, () -> get("s").getSet(Integer.class));
+    assertThrows(Depset.TypeException.class, () -> get("s").getSet(Integer.class));
   }
 
   @Test
@@ -80,7 +78,7 @@
     exec("s = depset(direct = ['a', 'b'])");
     assertThat(get("s").getSet(String.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").getSet(Object.class)).containsExactly("a", "b").inOrder();
-    assertThrows(SkylarkNestedSet.TypeException.class, () -> get("s").getSet(Integer.class));
+    assertThrows(Depset.TypeException.class, () -> get("s").getSet(Integer.class));
   }
 
   @Test
@@ -88,7 +86,7 @@
     exec("s = depset(items = ['a', 'b'])");
     assertThat(get("s").getSet(String.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").getSet(Object.class)).containsExactly("a", "b").inOrder();
-    assertThrows(SkylarkNestedSet.TypeException.class, () -> get("s").getSet(Integer.class));
+    assertThrows(Depset.TypeException.class, () -> get("s").getSet(Integer.class));
   }
 
 
@@ -98,7 +96,7 @@
     assertThat(get("s").toCollection(String.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").toCollection(Object.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").toCollection()).containsExactly("a", "b").inOrder();
-    assertThrows(SkylarkNestedSet.TypeException.class, () -> get("s").toCollection(Integer.class));
+    assertThrows(Depset.TypeException.class, () -> get("s").toCollection(Integer.class));
   }
 
   @Test
@@ -107,7 +105,7 @@
     assertThat(get("s").toCollection(String.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").toCollection(Object.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").toCollection()).containsExactly("a", "b").inOrder();
-    assertThrows(SkylarkNestedSet.TypeException.class, () -> get("s").toCollection(Integer.class));
+    assertThrows(Depset.TypeException.class, () -> get("s").toCollection(Integer.class));
   }
 
   @Test
@@ -116,7 +114,7 @@
     assertThat(get("s").toCollection(String.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").toCollection(Object.class)).containsExactly("a", "b").inOrder();
     assertThat(get("s").toCollection()).containsExactly("a", "b").inOrder();
-    assertThrows(SkylarkNestedSet.TypeException.class, () -> get("s").toCollection(Integer.class));
+    assertThrows(Depset.TypeException.class, () -> get("s").toCollection(Integer.class));
   }
 
   @Test
@@ -316,7 +314,7 @@
 
   private void assertContainsInOrder(String statement, Object... expectedElements)
       throws Exception {
-    assertThat(((SkylarkNestedSet) eval(statement)).toCollection())
+    assertThat(((Depset) eval(statement)).toCollection())
         .containsExactly(expectedElements)
         .inOrder();
   }
@@ -369,7 +367,7 @@
         "  s2 = s1.union(['b'])",
         "  return s1",
         "s = func()");
-    assertThat(((SkylarkNestedSet) lookup("s")).toCollection()).isEqualTo(ImmutableList.of("a"));
+    assertThat(((Depset) lookup("s")).toCollection()).isEqualTo(ImmutableList.of("a"));
   }
 
   @Test
@@ -381,7 +379,7 @@
         "  t += ['a']",
         "  return t",
         "s = func()");
-    assertThat(get("s")).isInstanceOf(SkylarkNestedSet.class);
+    assertThat(get("s")).isInstanceOf(Depset.class);
     assertThat(get("s").toCollection()).containsExactly("a");
   }
 
@@ -473,9 +471,8 @@
     assertThat(lookup("x")).isEqualTo("depset([2, 4, 6, 3, 5], order = \"topological\")");
   }
 
-  @SuppressWarnings("unchecked")
-  private SkylarkNestedSet get(String varname) throws Exception {
-    return (SkylarkNestedSet) lookup(varname);
+  private Depset get(String varname) throws Exception {
+    return (Depset) lookup(varname);
   }
 
   @Test
@@ -496,15 +493,15 @@
     //  (b) at least one order is "default"
 
     for (Order first : Order.values()) {
-      SkylarkNestedSet s1 = SkylarkNestedSet.of(first, Tuple.of("1", "11"), null);
+      Depset s1 = Depset.of(first, Tuple.of("1", "11"), null);
 
       for (Order second : Order.values()) {
-        SkylarkNestedSet s2 = SkylarkNestedSet.of(second, Tuple.of("2", "22"), null);
+        Depset s2 = Depset.of(second, Tuple.of("2", "22"), null);
 
         boolean compatible = true;
 
         try {
-          SkylarkNestedSet.of(s1, s2, null);
+          Depset.of(s1, s2, null);
         } catch (Exception ex) {
           compatible = false;
         }
@@ -527,10 +524,10 @@
     MergeStrategy strategy =
         new MergeStrategy() {
           @Override
-          public SkylarkNestedSet merge(SkylarkNestedSet[] sets) throws Exception {
-            SkylarkNestedSet union = SkylarkNestedSet.of(sets[0], sets[1], null);
-            union = SkylarkNestedSet.of(union, sets[2], null);
-            union = SkylarkNestedSet.of(union, sets[3], null);
+          public Depset merge(Depset[] sets) throws Exception {
+            Depset union = Depset.of(sets[0], sets[1], null);
+            union = Depset.of(union, sets[2], null);
+            union = Depset.of(union, sets[3], null);
 
             return union;
           }
@@ -548,10 +545,10 @@
     MergeStrategy strategy =
         new MergeStrategy() {
           @Override
-          public SkylarkNestedSet merge(SkylarkNestedSet[] sets) throws Exception {
-            SkylarkNestedSet leftUnion = SkylarkNestedSet.of(sets[0], sets[1], null);
-            SkylarkNestedSet rightUnion = SkylarkNestedSet.of(sets[2], sets[3], null);
-            SkylarkNestedSet union = SkylarkNestedSet.of(leftUnion, rightUnion, null);
+          public Depset merge(Depset[] sets) throws Exception {
+            Depset leftUnion = Depset.of(sets[0], sets[1], null);
+            Depset rightUnion = Depset.of(sets[2], sets[3], null);
+            Depset union = Depset.of(leftUnion, rightUnion, null);
 
             return union;
           }
@@ -569,10 +566,10 @@
     MergeStrategy strategy =
         new MergeStrategy() {
           @Override
-          public SkylarkNestedSet merge(SkylarkNestedSet[] sets) throws Exception {
-            SkylarkNestedSet union = SkylarkNestedSet.of(sets[2], sets[3], null);
-            union = SkylarkNestedSet.of(sets[1], union, null);
-            union = SkylarkNestedSet.of(sets[0], union, null);
+          public Depset merge(Depset[] sets) throws Exception {
+            Depset union = Depset.of(sets[2], sets[3], null);
+            union = Depset.of(sets[1], union, null);
+            union = Depset.of(sets[0], union, null);
 
             return union;
           }
@@ -598,14 +595,14 @@
   }
 
   private interface MergeStrategy {
-    SkylarkNestedSet merge(SkylarkNestedSet[] sets) throws Exception;
+    Depset merge(Depset[] sets) throws Exception;
   }
 
   private void runComplexOrderTest(
       MergeStrategy strategy, List<String> preOrder, List<String> postOrder) throws Exception {
     Map<Order, List<String>> expected = createExpectedMap(preOrder, postOrder);
     for (Order order : Order.values()) {
-      SkylarkNestedSet union = strategy.merge(makeFourSets(order));
+      Depset union = strategy.merge(makeFourSets(order));
       assertThat(union.toCollection()).containsExactlyElementsIn(expected.get(order)).inOrder();
     }
   }
@@ -625,12 +622,12 @@
     return order == Order.STABLE_ORDER || order == Order.COMPILE_ORDER;
   }
 
-  private SkylarkNestedSet[] makeFourSets(Order order) throws Exception {
-    return new SkylarkNestedSet[] {
-      SkylarkNestedSet.of(order, Tuple.of("1", "11"), null),
-      SkylarkNestedSet.of(order, Tuple.of("2", "22"), null),
-      SkylarkNestedSet.of(order, Tuple.of("3", "33"), null),
-      SkylarkNestedSet.of(order, Tuple.of("4", "44"), null)
+  private Depset[] makeFourSets(Order order) throws Exception {
+    return new Depset[] {
+      Depset.of(order, Tuple.of("1", "11"), null),
+      Depset.of(order, Tuple.of("2", "22"), null),
+      Depset.of(order, Tuple.of("3", "33"), null),
+      Depset.of(order, Tuple.of("4", "44"), null)
     };
   }
 }