fix #4919, macroexpander bug in "using" etc.

src/julia-syntax.scm

@@ -3007,6 +3007,7 @@ So far only the second case can actually occur.
 	(else
 	 (case (car e)
 	   ((escape) (cadr e))
+	   ((using import importall export) (map unescape e))
 	   ((macrocall)
 	    `(macrocall ,.(map (lambda (x)
 				 (resolve-expansion-vars- x env m inarg))

src/module.c

@@ -45,6 +45,7 @@ JL_CALLABLE(jl_f_new_module)
 
 static jl_binding_t *new_binding(jl_sym_t *name)
 {
+    assert(jl_is_symbol(name));
     jl_binding_t *b = (jl_binding_t*)allocb(sizeof(jl_binding_t));
     b->name = name;
     b->value = NULL;

src/toplevel.c

@@ -312,7 +312,8 @@ jl_value_t *jl_toplevel_eval_flex(jl_value_t *e, int fast)
         jl_module_t *m = eval_import_path(ex->args);
         if (m==NULL) return jl_nothing;
         jl_sym_t *name = (jl_sym_t*)jl_cellref(ex->args, jl_array_len(ex->args)-1);
-        assert(jl_is_symbol(name));
+        if (!jl_is_symbol(name))
+            jl_error("syntax: malformed \"importall\" statement");
         m = (jl_module_t*)jl_eval_global_var(m, name);
         if (!jl_is_module(m))
 	    jl_errorf("invalid %s statement: name exists but does not refer to a module", ex->head->name);
@@ -324,7 +325,8 @@ jl_value_t *jl_toplevel_eval_flex(jl_value_t *e, int fast)
         jl_module_t *m = eval_import_path(ex->args);
         if (m==NULL) return jl_nothing;
         jl_sym_t *name = (jl_sym_t*)jl_cellref(ex->args, jl_array_len(ex->args)-1);
-        assert(jl_is_symbol(name));
+        if (!jl_is_symbol(name))
+            jl_error("syntax: malformed \"using\" statement");
         jl_module_t *u = (jl_module_t*)jl_eval_global_var(m, name);
         if (jl_is_module(u)) {
             jl_module_using(jl_current_module, u);
@@ -339,15 +341,18 @@ jl_value_t *jl_toplevel_eval_flex(jl_value_t *e, int fast)
         jl_module_t *m = eval_import_path(ex->args);
         if (m==NULL) return jl_nothing;
         jl_sym_t *name = (jl_sym_t*)jl_cellref(ex->args, jl_array_len(ex->args)-1);
-        assert(jl_is_symbol(name));
+        if (!jl_is_symbol(name))
+            jl_error("syntax: malformed \"import\" statement");
         jl_module_import(jl_current_module, m, name);
         return jl_nothing;
     }
 
     if (ex->head == export_sym) {
         for(size_t i=0; i < jl_array_len(ex->args); i++) {
-            jl_module_export(jl_current_module,
-                             (jl_sym_t*)jl_cellref(ex->args, i));
+            jl_sym_t *name = (jl_sym_t*)jl_cellref(ex->args, i);
+            if (!jl_is_symbol(name))
+                jl_error("syntax: malformed \"export\" statement");
+            jl_module_export(jl_current_module, name);
         }
         return jl_nothing;
     }