Index and slice calls are implemented as separate AST nodes rather th…

…an special

function calls.

--
MOS_MIGRATED_REVID=133262955

src/main/java/com/google/devtools/build/lib/syntax/IndexExpression.java

@@ -44,14 +44,7 @@ public String toString() {
   Object doEval(Environment env) throws EvalException, InterruptedException {
     Object objValue = obj.eval(env);
     Object keyValue = key.eval(env);
-    return eval(objValue, keyValue, getLocation(), env);
-  }
-
-  /**
-   * Returns the field of the given key of the struct objValue, or null if no such field exists.
-   */
-  private Object eval(Object objValue, Object keyValue, Location loc, Environment env)
-      throws EvalException {
+    Location loc = getLocation();
 
     if (objValue instanceof SkylarkIndexable) {
       Object result = ((SkylarkIndexable) objValue).getIndex(keyValue, loc);

src/main/java/com/google/devtools/build/lib/syntax/LValue.java

@@ -151,6 +151,7 @@ private static void validate(ValidationEnvironment env, Location loc, Expression
       return;
     }
     if (expr instanceof IndexExpression) {
+      expr.validate(env);
       return;
     }
     throw new EvalException(loc,

src/main/java/com/google/devtools/build/lib/syntax/SliceExpression.java

@@ -66,14 +66,8 @@ Object doEval(Environment env) throws EvalException, InterruptedException {
     Object startValue = start.eval(env);
     Object endValue = end.eval(env);
     Object stepValue = step.eval(env);
-    return eval(objValue, startValue, endValue, stepValue, getLocation(), env);
-  }
+    Location loc = getLocation();
 
-  /**
-   * Returns the result of the given slice, or null if no such slice is supported.
-   */
-  private Object eval(Object objValue, Object startValue, Object endValue, Object stepValue,
-      Location loc, Environment env) throws EvalException {
     if (objValue instanceof SkylarkList) {
       SkylarkList<Object> list = (SkylarkList<Object>) objValue;
       Object slice = list.getSlice(startValue, endValue, stepValue, loc);