2 files changed, 4 insertions, 2 deletions
diff --git a/src/vhdl/vhdl-sem_expr.adb b/src/vhdl/vhdl-sem_expr.adb
index 94d0908f4..332a11dfc 100644
--- a/src/vhdl/vhdl-sem_expr.adb
+++ b/src/vhdl/vhdl-sem_expr.adb
@@ -6071,7 +6071,7 @@ package body Vhdl.Sem_Expr is
       Cond_Type : Iir;
    begin
       Cond_Type := Get_Type (Cond);
-      if Cond_Type = Null_Iir then
+      if Cond_Type = Null_Iir or else Is_Error (Cond_Type) then
          --  Error.
          return Cond;
       end if;
diff --git a/src/vhdl/vhdl-sem_psl.adb b/src/vhdl/vhdl-sem_psl.adb
index f498f0115..06cac1072 100644
--- a/src/vhdl/vhdl-sem_psl.adb
+++ b/src/vhdl/vhdl-sem_psl.adb
@@ -361,7 +361,9 @@ package body Vhdl.Sem_Psl is
       if not Is_Overload_List (Expr_Type)
         and then not Is_Psl_Boolean_Type (Expr_Type)
       then
-         Error_Msg_Sem (+Expr, "type of expression must be boolean");
+         if Get_Kind (Expr_Type) /= Iir_Kind_Error then
+            Error_Msg_Sem (+Expr, "type of expression must be boolean");
+         end if;
          return PSL.Hash.Get_PSL_Node (HDL_Node (Expr), Get_Location (Expr));
       else
          return Convert_Bool (Expr);