diff --git a/hscript/Interp.hx b/hscript/Interp.hx
index b1b6cb3..ffc9029 100644
--- a/hscript/Interp.hx
+++ b/hscript/Interp.hx
@@ -542,6 +542,10 @@ class Interp {
 			return expr(e);
 		case ECheckType(e,_):
 			return expr(e);
+		#if hscript_extraExprs
+		default:
+			throw '$e is unknown';
+		#end
 		}
 		return null;
 	}
diff --git a/hscript/Printer.hx b/hscript/Printer.hx
index b6310a8..035fa8e 100644
--- a/hscript/Printer.hx
+++ b/hscript/Printer.hx
@@ -332,6 +332,10 @@ class Printer {
 			add(" : ");
 			addType(t);
 			add(")");
+		#if hscript_extraExprs
+		default:
+			throw '${#if hscriptPos e.e #else e #end} is unknown';
+		#end
 		}
 	}
 
diff --git a/hscript/Tools.hx b/hscript/Tools.hx
index 2153d3f..cecf7db 100644
--- a/hscript/Tools.hx
+++ b/hscript/Tools.hx
@@ -58,6 +58,10 @@ class Tools {
 			if( def != null ) f(def);
 		case EMeta(name, args, e): if( args != null ) for( a in args ) f(a); f(e);
 		case ECheckType(e,_): f(e);
+		#if hscript_extraExprs
+		default:
+			throw '${expr(e)} is unknown';
+		#end
 		}
 	}
 
@@ -88,6 +92,7 @@ class Tools {
 		case ESwitch(e, cases, def): ESwitch(f(e), [for( c in cases ) { values : [for( v in c.values ) f(v)], expr : f(c.expr) } ], def == null ? null : f(def));
 		case EMeta(name, args, e): EMeta(name, args == null ? null : [for( a in args ) f(a)], f(e));
 		case ECheckType(e,t): ECheckType(f(e), t);
+		default: null;
 		}
 		return mk(edef, e);
 	}