diff --git a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
index e24d97f..a5190a6 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/FuncallExpression.java
@@ -533,7 +533,9 @@
 
   @Override
   SkylarkType validate(ValidationEnvironment env) throws EvalException {
-    // TODO(bazel-team): implement semantical check.
+    for (Argument arg : args) {
+      arg.getValue().validate(env);
+    }
 
     if (obj != null) {
       // TODO(bazel-team): validate function calls on objects too.
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkFunction.java b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkFunction.java
index 3af91f1..11f1877 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SkylarkFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SkylarkFunction.java
@@ -13,7 +13,6 @@
 // limitations under the License.
 package com.google.devtools.build.lib.syntax;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
@@ -52,7 +51,6 @@
   /**
    * Configures the parameter of this Skylark function using the annotation.
    */
-  @VisibleForTesting
   public void configure(SkylarkBuiltin annotation) {
     Preconditions.checkState(!configured);
     Preconditions.checkArgument(getName().equals(annotation.name()),