Issue 12158. Report error when user code uses 'native' clause.

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java

Index: editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
diff --git a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
index f8d5f0b9fde48c4ed3057fae440124cdc3a4cbb4..c460d86df84b71d78ab6bac31541e657fa38262b 100644
--- a/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
+++ b/editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/internal/verifier/ErrorVerifier.java
@@ -61,6 +61,7 @@ import com.google.dart.engine.ast.MapLiteral;
 import com.google.dart.engine.ast.MapLiteralEntry;
 import com.google.dart.engine.ast.MethodDeclaration;
 import com.google.dart.engine.ast.MethodInvocation;
+import com.google.dart.engine.ast.NativeClause;
 import com.google.dart.engine.ast.NativeFunctionBody;
 import com.google.dart.engine.ast.NodeList;
 import com.google.dart.engine.ast.NormalFormalParameter;
@@ -735,6 +736,15 @@ public class ErrorVerifier extends RecursiveASTVisitor<Void> {
   }
 
   @Override
+  public Void visitNativeClause(NativeClause node) {
+    // TODO(brianwilkerson) Figure out the right rule for when 'native' is allowed.
+    if (!isInSystemLibrary) {
+      errorReporter.reportError(ParserErrorCode.NATIVE_CLAUSE_IN_NON_SDK_CODE, node);
+    }
+    return super.visitNativeClause(node);
+  }
+
+  @Override
   public Void visitNativeFunctionBody(NativeFunctionBody node) {
     checkForNativeFunctionBodyInNonSDKCode(node);
     return super.visitNativeFunctionBody(node);