Add 'did you mean' suggestion when accessing an undefined variable.

--
PiperOrigin-RevId: 143373605
MOS_MIGRATED_REVID=143373605
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 b7c2d59..30b9417 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
@@ -832,15 +832,13 @@
 
   @Override
   void validate(ValidationEnvironment env) throws EvalException {
-    for (Argument.Passed arg : args) {
-      arg.getValue().validate(env);
-    }
-
     if (obj != null) {
       obj.validate(env);
-    } else if (!env.hasSymbolInEnvironment(func.getName())) {
-      throw new EvalException(getLocation(),
-          String.format("function '%s' does not exist", func.getName()));
+    } else {
+      func.validate(env);
+    }
+    for (Argument.Passed arg : args) {
+      arg.getValue().validate(env);
     }
   }