diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
index 543f35e..f2690c6 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppLinkActionBuilder.java
@@ -554,7 +554,7 @@
         isLTOIndexing
             ? new CppLinkVariablesExtension(
                 configuration,
-                ImmutableMap.of(),
+                ImmutableMap.<Artifact, Artifact>of(),
                 needWholeArchive,
                 linkerInputs,
                 runtimeLinkerInputs,
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionFunction.java
index 9d9cafd..cce4a82 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionFunction.java
@@ -609,7 +609,7 @@
             expandedArtifacts.put(input, expansionBuilder.build());
           } else if (value instanceof TreeArtifactValue) {
             TreeArtifactValue treeValue = (TreeArtifactValue) value;
-            expandedArtifacts.put(input, ImmutableSet.copyOf(treeValue.getChildren()));
+            expandedArtifacts.put(input, ImmutableSet.<Artifact>copyOf(treeValue.getChildren()));
             inputArtifactData.putAll(treeValue.getChildValues());
 
             // Again, we cache the "digest" of the value for cache checking.