Code cleanup

RELNOTES: None.
PiperOrigin-RevId: 218735707
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Parser.java b/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
index 9370cfb..3e9ebd5 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
@@ -29,7 +29,6 @@
 import com.google.devtools.build.lib.syntax.DictionaryLiteral.DictionaryEntryLiteral;
 import com.google.devtools.build.lib.syntax.IfStatement.ConditionalStatements;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.List;
@@ -639,7 +638,7 @@
           nextToken();
           // check for the empty tuple literal
           if (token.kind == TokenKind.RPAREN) {
-            ListLiteral literal = ListLiteral.makeTuple(Collections.emptyList());
+            ListLiteral literal = ListLiteral.makeTuple(ImmutableList.of());
             setLocation(literal, start, token.right);
             nextToken();
             return literal;
@@ -811,7 +810,7 @@
     switch (token.kind) {
       case RBRACKET: // singleton List
         {
-          ListLiteral literal = ListLiteral.makeList(Collections.singletonList(expression));
+          ListLiteral literal = ListLiteral.makeList(ImmutableList.of(expression));
           setLocation(literal, start, token.right);
           nextToken();
           return literal;