diff --git a/parse.y b/parse.y
index 64fe44da7..8af33f0b9 100644
--- a/parse.y
+++ b/parse.y
@@ -4868,10 +4868,22 @@ module
      keyword. The syntax for modules programs, and interfaces is
      almost identical, so let semantics sort out the differences. */
 module_start
-  : K_module      { $$ = K_module; }
-  | K_macromodule { $$ = K_module; }
-  | K_program     { $$ = K_program; }
-  | K_interface   { $$ = K_interface; }
+  : K_module
+      { pform_error_in_generate(@1, "module declaration");
+        $$ = K_module;
+      }
+  | K_macromodule
+      { pform_error_in_generate(@1, "module declaration");
+        $$ = K_module;
+      }
+  | K_program
+      { pform_error_in_generate(@1, "program declaration");
+        $$ = K_program;
+      }
+  | K_interface
+      { pform_error_in_generate(@1, "interface declaration");
+        $$ = K_interface;
+      }
   ;
 
 module_end
@@ -5262,6 +5274,7 @@ module_item
   | attribute_list_opt assertion_item
 
   | timeunits_declaration
+      { pform_error_in_generate(@1, "timeunit declaration"); }
 
   | class_declaration
 
@@ -5330,8 +5343,9 @@ module_item
 
   | attribute_list_opt K_specparam
       { if (pform_in_interface())
-	      yyerror(@1, "error: specparam declarations are not allowed "
+	      yyerror(@2, "error: specparam declarations are not allowed "
 			  "in interfaces.");
+        pform_error_in_generate(@2, "specparam declaration");
       }
     specparam_decl ';'
 
@@ -5341,7 +5355,9 @@ module_item
       { if (pform_in_interface())
 	      yyerror(@1, "error: specify blocks are not allowed "
 			  "in interfaces.");
+        pform_error_in_generate(@1, "specify block");
       }
+
     specify_item_list_opt K_endspecify
 
   | K_specify error K_endspecify
diff --git a/pform.cc b/pform.cc
index dd171773c..157231a69 100644
--- a/pform.cc
+++ b/pform.cc
@@ -780,6 +780,15 @@ PGenerate* pform_parent_generate(void)
       return pform_cur_generate;
 }
 
+bool pform_error_in_generate(const vlltype&loc, const char *type)
+{
+	if (!pform_parent_generate())
+		return false;
+
+	VLerror(loc, "error: %s is not allowed in generate block.", type);
+	return true;
+}
+
 void pform_bind_attributes(map<perm_string,PExpr*>&attributes,
 			   list<named_pexpr_t>*attr, bool keep_attrs)
 {
@@ -1212,7 +1221,8 @@ void pform_set_timeunit(const char*txt, bool initial_decl)
       if (get_time_unit_prec(txt, val, true)) return;
 
       PScopeExtra*scope = dynamic_cast<PScopeExtra*>(lexical_scope);
-      assert(scope);
+      if (!scope)
+	    return;
 
       if (initial_decl) {
             scope->time_unit = val;
@@ -1249,7 +1259,8 @@ void pform_set_timeprec(const char*txt, bool initial_decl)
       if (get_time_unit_prec(txt, val, false)) return;
 
       PScopeExtra*scope = dynamic_cast<PScopeExtra*>(lexical_scope);
-      assert(scope);
+      if (!scope)
+	    return;
 
       if (initial_decl) {
             scope->time_precision = val;
@@ -3288,7 +3299,11 @@ void pform_set_specparam(const struct vlltype&loc, perm_string name,
 {
       assert(! pform_cur_module.empty());
       Module*scope = pform_cur_module.front();
-      assert(scope == lexical_scope);
+      if (scope != lexical_scope) {
+	    delete range;
+	    delete expr;
+	    return;
+      }
 
       assert(expr);
       Module::param_expr_t*parm = new Module::param_expr_t();
diff --git a/pform.h b/pform.h
index 52199eaad..861d59e67 100644
--- a/pform.h
+++ b/pform.h
@@ -323,6 +323,8 @@ extern void pform_endgenerate(bool end_conditional);
  */
 extern PGenerate* pform_parent_generate(void);
 
+bool pform_error_in_generate(const vlltype&loc, const char *type);
+
 extern void pform_make_elab_task(const struct vlltype&li,
                                  perm_string name,
                                  const std::list<PExpr*>&params);