diff --git a/tool/src/org/antlr/v4/codegen/model/SemPred.java b/tool/src/org/antlr/v4/codegen/model/SemPred.java
index 5722d3ae5..5bed0fe80 100644
--- a/tool/src/org/antlr/v4/codegen/model/SemPred.java
+++ b/tool/src/org/antlr/v4/codegen/model/SemPred.java
@@ -38,7 +38,7 @@ public class SemPred extends Action {
 
 	public SemPred(OutputModelFactory factory, GrammarAST ast) {
 		super(factory,ast);
-		this.msg = ((PredAST)ast).getOption("msg");
+		this.msg = ((PredAST)ast).getOption("fail");
 		if ( msg==null ) {
 			msg = "failed predicate: "+ast.getText();
 		}