1 files changed, 4 insertions, 0 deletions
diff --git a/src/synth/synth-stmts.adb b/src/synth/synth-stmts.adb
index 05003e40e..63354f00a 100644
--- a/src/synth/synth-stmts.adb
+++ b/src/synth/synth-stmts.adb
@@ -1925,6 +1925,10 @@ package body Synth.Stmts is
 
       --  Handle the condition as an if.
       Cond := Get_Condition_Clause (Stmt);
+      if Cond = Null_Node then
+         Error_Msg_Synth (+Stmt, "expect wait condition");
+         return;
+      end if;
       Cond_Val := Synth_Expression (C.Inst, Cond);
 
       Push_Phi;