Skylark: Remove static type checking of variables/functions.

There are still some static checks (check existence of variable/function,
readonly variables, etc.). More cleanup will come later.

--
MOS_MIGRATED_REVID=90979748
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
index 9c59989..414429e 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/LoadStatement.java
@@ -75,9 +75,8 @@
     if (!importPath.isAbsolute() && importPath.segmentCount() > 1) {
       throw new EvalException(getLocation(), String.format(PATH_ERROR_MSG, importPath));
     }
-    // TODO(bazel-team): implement semantical check.
     for (Ident symbol : symbols) {
-      env.update(symbol.getName(), SkylarkType.UNKNOWN, getLocation());
+      env.declare(symbol.getName(), getLocation());
     }
   }
 }