Skylark: DictionaryLiteral is immutable (like every dict).

--
MOS_MIGRATED_REVID=88440711

2 files changed, 4 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java
index 778bc7bd8b..57df6483e2 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/BinaryOperatorExpression.java
@@ -14,6 +14,7 @@
 package com.google.devtools.build.lib.syntax;
 
 import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.devtools.build.lib.syntax.ClassObject.SkylarkClassObject;
@@ -141,7 +142,7 @@ public final class BinaryOperatorExpression extends Expression {
           Map<Object, Object> result = Maps.newHashMapWithExpectedSize(ldict.size() + rdict.size());
           result.putAll(ldict);
           result.putAll(rdict);
-          return result;
+          return ImmutableMap.copyOf(result);
         }
 
         if (env.isSkylarkEnabled()
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java b/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java
index 0b926f6ae1..e991504488 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/DictionaryLiteral.java
@@ -14,6 +14,7 @@
 package com.google.devtools.build.lib.syntax;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -78,7 +79,7 @@ public class DictionaryLiteral extends Expression {
       }
       map.put(entry.key.eval(env), entry.value.eval(env));
     }
-    return map;
+    return ImmutableMap.copyOf(map);
   }
 
   @Override